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History of life on Earth Mass Extinctions.

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Page 1: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

History of life on Earth Mass Extinctions

Agenda or Summary LayoutA summary of the topics discussed

1

2

3

4

Discussion Item OneExplanation of Mass extinctions

Discussion Item TwoThe five major mass extinctions

Discussion Item ThreeTwo particular Extinctions

Discussion Item FourSixth major extinction

Mass Extinctions

Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists

Remember that there are two types of extinctions

They are natural and man made extinctions

Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed

But there are times when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years

This is called a mass extinction

What are they

The Five Major Mass Extinctions

The earliest known mass extinction occurred about 439 million years ago and was caused by a drop in sea levels

The sea levels dropped because of the formation of glaciers

The sea levels rises as the glaciers started to melt

The first mass extinction

The Five Major Mass Extinctions

The second extinction occurred about 364 million years agoIt is not known what caused this extinction

The third extinction occurred about 250 million years agoIt may have been caused by comet or asteroid impact or volcanic floods

The second and third mass extinction

The Five Major Mass Extinctions

The fourth mass extinction occurred about 199 million to 214 million years ago

It was caused when volcanoes erupted releasing large amounts of lava

This is turn lead to global warming

The fourth mass extinction

The Five Major Mass Extinctions

The fifth mass extinction occurred about 65 million years ago

There are several possible causesbull asteroid impact on the Yucatan Peninsula which is in

the Gulf of Mexicobull gradual climate changebull volcanic eruptions

The fifth mass extinction

Two Particular Extinctions

Of the five mass extinctions two stand out

These were the one that occurred 250 million years ago and the one that occurred 65 million years ago

The mass extinction that occurred 250 million years ago was the most serious one

The most famous mass extinction occurred 65 million years ago the extinction of the dinosaurs

Two Particular Extinctions

During this extinction almost 90 all species became extinct

This included 84 of marine genera and about 70 of land species plants insects and vertebrate animals

The mass extinction of 250 million years ago

Two Particular Extinctions

The dinosaurs appeared about 245 million years ago

They flourished during the Jurassic Period

This period occurred about 208 to 143 million years ago

The dinosaurs dominated the land and air and some of them even lived in water

Two Particular Extinctions

Birds and mammals also existed during this time

The dinosaurs then became extinct in a short period of 10 million years

This occurred about 65 million years ago

Of the marine families 16 marine genera 47 and 18 of the land vertebrate families also became extinct during this time

The mass extinction of 65 million years ago

Two Particular Extinctions

Scientists are not sure about the exact cause of this mass extinction

However the following are some of the conditions that occurred during this timeo there was a sharp drop in temperatureo the water of the seas evaporates

The mass extinction of 65 million years - Causes

Two Particular Extinctions

Many of the plants the source of food for the dinosaurs died out

Iridium was found in a thin layer of clay

Iridium is an element that is very rare on earth but common in meteorites

A huge crater was found in the Caribbean Sea

There were many volcanic eruptions in India

The mass extinction of 65 million years - Causes

Two Particular Extinctions

The above evidence lead to the formation of three hypothesis

The most common hypothesis is that an asteroid crashed onto Earth causing global climate change

The climate change lead to the mass extinction

The layer of iridium and the large crater in the Caribbean sea support this hypothesis

The mass extinction of 65 million years ago - Hypothesis

Two Particular Extinctions

This hypothesis deals with the continental drift theory movement of continents away from each other

It is believed that the continental drift led to the climate change

The mass extinction of 65 million years ago- Hypothesis 2

Two Particular Extinctions

This hypothesis deals with the volcanic activity in India

It is believed that this volcanic activity released particles into the air

These particles blocked out the sun for a long period of time

This resulted in the lowering of temperatures on Earth

Therefore many species died out because they could not adapt to the low temperature

The mass extinction of 65 million years ago ndash Hypothesis 3

Two Particular Extinctions

Scientists accept all three theories

Mass extinction was caused by climate change

The climate change was caused by the asteroid impact and volcanic activity

The mass extinction of 65 million years

The Holocene Epoch

The next major extinction is occurring presently

This is the sixth mass extinction

Human exploitation of the environment is the cause of this mass extinction

It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction

Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time

The sixth major extinction

Terminology

Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists

Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed

Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years

Jurassic Period period when dinosaurs flourished

Something for you to do

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

4 The first mass extinction was caused byhellip

A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above

5 The most famous extinction took placehellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and airB Water and airC Land and airD Water and land

9 Iridium ishellip

A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 3 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 4 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 5 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 6 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 7 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 2: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Agenda or Summary LayoutA summary of the topics discussed

1

2

3

4

Discussion Item OneExplanation of Mass extinctions

Discussion Item TwoThe five major mass extinctions

Discussion Item ThreeTwo particular Extinctions

Discussion Item FourSixth major extinction

Mass Extinctions

Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists

Remember that there are two types of extinctions

They are natural and man made extinctions

Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed

But there are times when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years

This is called a mass extinction

What are they

The Five Major Mass Extinctions

The earliest known mass extinction occurred about 439 million years ago and was caused by a drop in sea levels

The sea levels dropped because of the formation of glaciers

The sea levels rises as the glaciers started to melt

The first mass extinction

The Five Major Mass Extinctions

The second extinction occurred about 364 million years agoIt is not known what caused this extinction

The third extinction occurred about 250 million years agoIt may have been caused by comet or asteroid impact or volcanic floods

The second and third mass extinction

The Five Major Mass Extinctions

The fourth mass extinction occurred about 199 million to 214 million years ago

It was caused when volcanoes erupted releasing large amounts of lava

This is turn lead to global warming

The fourth mass extinction

The Five Major Mass Extinctions

The fifth mass extinction occurred about 65 million years ago

There are several possible causesbull asteroid impact on the Yucatan Peninsula which is in

the Gulf of Mexicobull gradual climate changebull volcanic eruptions

The fifth mass extinction

Two Particular Extinctions

Of the five mass extinctions two stand out

These were the one that occurred 250 million years ago and the one that occurred 65 million years ago

The mass extinction that occurred 250 million years ago was the most serious one

The most famous mass extinction occurred 65 million years ago the extinction of the dinosaurs

Two Particular Extinctions

During this extinction almost 90 all species became extinct

This included 84 of marine genera and about 70 of land species plants insects and vertebrate animals

The mass extinction of 250 million years ago

Two Particular Extinctions

The dinosaurs appeared about 245 million years ago

They flourished during the Jurassic Period

This period occurred about 208 to 143 million years ago

The dinosaurs dominated the land and air and some of them even lived in water

Two Particular Extinctions

Birds and mammals also existed during this time

The dinosaurs then became extinct in a short period of 10 million years

This occurred about 65 million years ago

Of the marine families 16 marine genera 47 and 18 of the land vertebrate families also became extinct during this time

The mass extinction of 65 million years ago

Two Particular Extinctions

Scientists are not sure about the exact cause of this mass extinction

However the following are some of the conditions that occurred during this timeo there was a sharp drop in temperatureo the water of the seas evaporates

The mass extinction of 65 million years - Causes

Two Particular Extinctions

Many of the plants the source of food for the dinosaurs died out

Iridium was found in a thin layer of clay

Iridium is an element that is very rare on earth but common in meteorites

A huge crater was found in the Caribbean Sea

There were many volcanic eruptions in India

The mass extinction of 65 million years - Causes

Two Particular Extinctions

The above evidence lead to the formation of three hypothesis

The most common hypothesis is that an asteroid crashed onto Earth causing global climate change

The climate change lead to the mass extinction

The layer of iridium and the large crater in the Caribbean sea support this hypothesis

The mass extinction of 65 million years ago - Hypothesis

Two Particular Extinctions

This hypothesis deals with the continental drift theory movement of continents away from each other

It is believed that the continental drift led to the climate change

The mass extinction of 65 million years ago- Hypothesis 2

Two Particular Extinctions

This hypothesis deals with the volcanic activity in India

It is believed that this volcanic activity released particles into the air

These particles blocked out the sun for a long period of time

This resulted in the lowering of temperatures on Earth

Therefore many species died out because they could not adapt to the low temperature

The mass extinction of 65 million years ago ndash Hypothesis 3

Two Particular Extinctions

Scientists accept all three theories

Mass extinction was caused by climate change

The climate change was caused by the asteroid impact and volcanic activity

The mass extinction of 65 million years

The Holocene Epoch

The next major extinction is occurring presently

This is the sixth mass extinction

Human exploitation of the environment is the cause of this mass extinction

It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction

Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time

The sixth major extinction

Terminology

Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists

Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed

Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years

Jurassic Period period when dinosaurs flourished

Something for you to do

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

4 The first mass extinction was caused byhellip

A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above

5 The most famous extinction took placehellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and airB Water and airC Land and airD Water and land

9 Iridium ishellip

A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 3 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 4 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 5 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 6 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 7 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 3: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Mass Extinctions

Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists

Remember that there are two types of extinctions

They are natural and man made extinctions

Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed

But there are times when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years

This is called a mass extinction

What are they

The Five Major Mass Extinctions

The earliest known mass extinction occurred about 439 million years ago and was caused by a drop in sea levels

The sea levels dropped because of the formation of glaciers

The sea levels rises as the glaciers started to melt

The first mass extinction

The Five Major Mass Extinctions

The second extinction occurred about 364 million years agoIt is not known what caused this extinction

The third extinction occurred about 250 million years agoIt may have been caused by comet or asteroid impact or volcanic floods

The second and third mass extinction

The Five Major Mass Extinctions

The fourth mass extinction occurred about 199 million to 214 million years ago

It was caused when volcanoes erupted releasing large amounts of lava

This is turn lead to global warming

The fourth mass extinction

The Five Major Mass Extinctions

The fifth mass extinction occurred about 65 million years ago

There are several possible causesbull asteroid impact on the Yucatan Peninsula which is in

the Gulf of Mexicobull gradual climate changebull volcanic eruptions

The fifth mass extinction

Two Particular Extinctions

Of the five mass extinctions two stand out

These were the one that occurred 250 million years ago and the one that occurred 65 million years ago

The mass extinction that occurred 250 million years ago was the most serious one

The most famous mass extinction occurred 65 million years ago the extinction of the dinosaurs

Two Particular Extinctions

During this extinction almost 90 all species became extinct

This included 84 of marine genera and about 70 of land species plants insects and vertebrate animals

The mass extinction of 250 million years ago

Two Particular Extinctions

The dinosaurs appeared about 245 million years ago

They flourished during the Jurassic Period

This period occurred about 208 to 143 million years ago

The dinosaurs dominated the land and air and some of them even lived in water

Two Particular Extinctions

Birds and mammals also existed during this time

The dinosaurs then became extinct in a short period of 10 million years

This occurred about 65 million years ago

Of the marine families 16 marine genera 47 and 18 of the land vertebrate families also became extinct during this time

The mass extinction of 65 million years ago

Two Particular Extinctions

Scientists are not sure about the exact cause of this mass extinction

However the following are some of the conditions that occurred during this timeo there was a sharp drop in temperatureo the water of the seas evaporates

The mass extinction of 65 million years - Causes

Two Particular Extinctions

Many of the plants the source of food for the dinosaurs died out

Iridium was found in a thin layer of clay

Iridium is an element that is very rare on earth but common in meteorites

A huge crater was found in the Caribbean Sea

There were many volcanic eruptions in India

The mass extinction of 65 million years - Causes

Two Particular Extinctions

The above evidence lead to the formation of three hypothesis

The most common hypothesis is that an asteroid crashed onto Earth causing global climate change

The climate change lead to the mass extinction

The layer of iridium and the large crater in the Caribbean sea support this hypothesis

The mass extinction of 65 million years ago - Hypothesis

Two Particular Extinctions

This hypothesis deals with the continental drift theory movement of continents away from each other

It is believed that the continental drift led to the climate change

The mass extinction of 65 million years ago- Hypothesis 2

Two Particular Extinctions

This hypothesis deals with the volcanic activity in India

It is believed that this volcanic activity released particles into the air

These particles blocked out the sun for a long period of time

This resulted in the lowering of temperatures on Earth

Therefore many species died out because they could not adapt to the low temperature

The mass extinction of 65 million years ago ndash Hypothesis 3

Two Particular Extinctions

Scientists accept all three theories

Mass extinction was caused by climate change

The climate change was caused by the asteroid impact and volcanic activity

The mass extinction of 65 million years

The Holocene Epoch

The next major extinction is occurring presently

This is the sixth mass extinction

Human exploitation of the environment is the cause of this mass extinction

It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction

Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time

The sixth major extinction

Terminology

Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists

Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed

Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years

Jurassic Period period when dinosaurs flourished

Something for you to do

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

4 The first mass extinction was caused byhellip

A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above

5 The most famous extinction took placehellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and airB Water and airC Land and airD Water and land

9 Iridium ishellip

A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 3 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 4 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 5 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 6 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 4: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

The Five Major Mass Extinctions

The earliest known mass extinction occurred about 439 million years ago and was caused by a drop in sea levels

The sea levels dropped because of the formation of glaciers

The sea levels rises as the glaciers started to melt

The first mass extinction

The Five Major Mass Extinctions

The second extinction occurred about 364 million years agoIt is not known what caused this extinction

The third extinction occurred about 250 million years agoIt may have been caused by comet or asteroid impact or volcanic floods

The second and third mass extinction

The Five Major Mass Extinctions

The fourth mass extinction occurred about 199 million to 214 million years ago

It was caused when volcanoes erupted releasing large amounts of lava

This is turn lead to global warming

The fourth mass extinction

The Five Major Mass Extinctions

The fifth mass extinction occurred about 65 million years ago

There are several possible causesbull asteroid impact on the Yucatan Peninsula which is in

the Gulf of Mexicobull gradual climate changebull volcanic eruptions

The fifth mass extinction

Two Particular Extinctions

Of the five mass extinctions two stand out

These were the one that occurred 250 million years ago and the one that occurred 65 million years ago

The mass extinction that occurred 250 million years ago was the most serious one

The most famous mass extinction occurred 65 million years ago the extinction of the dinosaurs

Two Particular Extinctions

During this extinction almost 90 all species became extinct

This included 84 of marine genera and about 70 of land species plants insects and vertebrate animals

The mass extinction of 250 million years ago

Two Particular Extinctions

The dinosaurs appeared about 245 million years ago

They flourished during the Jurassic Period

This period occurred about 208 to 143 million years ago

The dinosaurs dominated the land and air and some of them even lived in water

Two Particular Extinctions

Birds and mammals also existed during this time

The dinosaurs then became extinct in a short period of 10 million years

This occurred about 65 million years ago

Of the marine families 16 marine genera 47 and 18 of the land vertebrate families also became extinct during this time

The mass extinction of 65 million years ago

Two Particular Extinctions

Scientists are not sure about the exact cause of this mass extinction

However the following are some of the conditions that occurred during this timeo there was a sharp drop in temperatureo the water of the seas evaporates

The mass extinction of 65 million years - Causes

Two Particular Extinctions

Many of the plants the source of food for the dinosaurs died out

Iridium was found in a thin layer of clay

Iridium is an element that is very rare on earth but common in meteorites

A huge crater was found in the Caribbean Sea

There were many volcanic eruptions in India

The mass extinction of 65 million years - Causes

Two Particular Extinctions

The above evidence lead to the formation of three hypothesis

The most common hypothesis is that an asteroid crashed onto Earth causing global climate change

The climate change lead to the mass extinction

The layer of iridium and the large crater in the Caribbean sea support this hypothesis

The mass extinction of 65 million years ago - Hypothesis

Two Particular Extinctions

This hypothesis deals with the continental drift theory movement of continents away from each other

It is believed that the continental drift led to the climate change

The mass extinction of 65 million years ago- Hypothesis 2

Two Particular Extinctions

This hypothesis deals with the volcanic activity in India

It is believed that this volcanic activity released particles into the air

These particles blocked out the sun for a long period of time

This resulted in the lowering of temperatures on Earth

Therefore many species died out because they could not adapt to the low temperature

The mass extinction of 65 million years ago ndash Hypothesis 3

Two Particular Extinctions

Scientists accept all three theories

Mass extinction was caused by climate change

The climate change was caused by the asteroid impact and volcanic activity

The mass extinction of 65 million years

The Holocene Epoch

The next major extinction is occurring presently

This is the sixth mass extinction

Human exploitation of the environment is the cause of this mass extinction

It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction

Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time

The sixth major extinction

Terminology

Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists

Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed

Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years

Jurassic Period period when dinosaurs flourished

Something for you to do

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

4 The first mass extinction was caused byhellip

A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above

5 The most famous extinction took placehellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and airB Water and airC Land and airD Water and land

9 Iridium ishellip

A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 5: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

The Five Major Mass Extinctions

The second extinction occurred about 364 million years agoIt is not known what caused this extinction

The third extinction occurred about 250 million years agoIt may have been caused by comet or asteroid impact or volcanic floods

The second and third mass extinction

The Five Major Mass Extinctions

The fourth mass extinction occurred about 199 million to 214 million years ago

It was caused when volcanoes erupted releasing large amounts of lava

This is turn lead to global warming

The fourth mass extinction

The Five Major Mass Extinctions

The fifth mass extinction occurred about 65 million years ago

There are several possible causesbull asteroid impact on the Yucatan Peninsula which is in

the Gulf of Mexicobull gradual climate changebull volcanic eruptions

The fifth mass extinction

Two Particular Extinctions

Of the five mass extinctions two stand out

These were the one that occurred 250 million years ago and the one that occurred 65 million years ago

The mass extinction that occurred 250 million years ago was the most serious one

The most famous mass extinction occurred 65 million years ago the extinction of the dinosaurs

Two Particular Extinctions

During this extinction almost 90 all species became extinct

This included 84 of marine genera and about 70 of land species plants insects and vertebrate animals

The mass extinction of 250 million years ago

Two Particular Extinctions

The dinosaurs appeared about 245 million years ago

They flourished during the Jurassic Period

This period occurred about 208 to 143 million years ago

The dinosaurs dominated the land and air and some of them even lived in water

Two Particular Extinctions

Birds and mammals also existed during this time

The dinosaurs then became extinct in a short period of 10 million years

This occurred about 65 million years ago

Of the marine families 16 marine genera 47 and 18 of the land vertebrate families also became extinct during this time

The mass extinction of 65 million years ago

Two Particular Extinctions

Scientists are not sure about the exact cause of this mass extinction

However the following are some of the conditions that occurred during this timeo there was a sharp drop in temperatureo the water of the seas evaporates

The mass extinction of 65 million years - Causes

Two Particular Extinctions

Many of the plants the source of food for the dinosaurs died out

Iridium was found in a thin layer of clay

Iridium is an element that is very rare on earth but common in meteorites

A huge crater was found in the Caribbean Sea

There were many volcanic eruptions in India

The mass extinction of 65 million years - Causes

Two Particular Extinctions

The above evidence lead to the formation of three hypothesis

The most common hypothesis is that an asteroid crashed onto Earth causing global climate change

The climate change lead to the mass extinction

The layer of iridium and the large crater in the Caribbean sea support this hypothesis

The mass extinction of 65 million years ago - Hypothesis

Two Particular Extinctions

This hypothesis deals with the continental drift theory movement of continents away from each other

It is believed that the continental drift led to the climate change

The mass extinction of 65 million years ago- Hypothesis 2

Two Particular Extinctions

This hypothesis deals with the volcanic activity in India

It is believed that this volcanic activity released particles into the air

These particles blocked out the sun for a long period of time

This resulted in the lowering of temperatures on Earth

Therefore many species died out because they could not adapt to the low temperature

The mass extinction of 65 million years ago ndash Hypothesis 3

Two Particular Extinctions

Scientists accept all three theories

Mass extinction was caused by climate change

The climate change was caused by the asteroid impact and volcanic activity

The mass extinction of 65 million years

The Holocene Epoch

The next major extinction is occurring presently

This is the sixth mass extinction

Human exploitation of the environment is the cause of this mass extinction

It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction

Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time

The sixth major extinction

Terminology

Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists

Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed

Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years

Jurassic Period period when dinosaurs flourished

Something for you to do

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

4 The first mass extinction was caused byhellip

A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above

5 The most famous extinction took placehellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and airB Water and airC Land and airD Water and land

9 Iridium ishellip

A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 3 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 4 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 5 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 6 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 6: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

The Five Major Mass Extinctions

The fourth mass extinction occurred about 199 million to 214 million years ago

It was caused when volcanoes erupted releasing large amounts of lava

This is turn lead to global warming

The fourth mass extinction

The Five Major Mass Extinctions

The fifth mass extinction occurred about 65 million years ago

There are several possible causesbull asteroid impact on the Yucatan Peninsula which is in

the Gulf of Mexicobull gradual climate changebull volcanic eruptions

The fifth mass extinction

Two Particular Extinctions

Of the five mass extinctions two stand out

These were the one that occurred 250 million years ago and the one that occurred 65 million years ago

The mass extinction that occurred 250 million years ago was the most serious one

The most famous mass extinction occurred 65 million years ago the extinction of the dinosaurs

Two Particular Extinctions

During this extinction almost 90 all species became extinct

This included 84 of marine genera and about 70 of land species plants insects and vertebrate animals

The mass extinction of 250 million years ago

Two Particular Extinctions

The dinosaurs appeared about 245 million years ago

They flourished during the Jurassic Period

This period occurred about 208 to 143 million years ago

The dinosaurs dominated the land and air and some of them even lived in water

Two Particular Extinctions

Birds and mammals also existed during this time

The dinosaurs then became extinct in a short period of 10 million years

This occurred about 65 million years ago

Of the marine families 16 marine genera 47 and 18 of the land vertebrate families also became extinct during this time

The mass extinction of 65 million years ago

Two Particular Extinctions

Scientists are not sure about the exact cause of this mass extinction

However the following are some of the conditions that occurred during this timeo there was a sharp drop in temperatureo the water of the seas evaporates

The mass extinction of 65 million years - Causes

Two Particular Extinctions

Many of the plants the source of food for the dinosaurs died out

Iridium was found in a thin layer of clay

Iridium is an element that is very rare on earth but common in meteorites

A huge crater was found in the Caribbean Sea

There were many volcanic eruptions in India

The mass extinction of 65 million years - Causes

Two Particular Extinctions

The above evidence lead to the formation of three hypothesis

The most common hypothesis is that an asteroid crashed onto Earth causing global climate change

The climate change lead to the mass extinction

The layer of iridium and the large crater in the Caribbean sea support this hypothesis

The mass extinction of 65 million years ago - Hypothesis

Two Particular Extinctions

This hypothesis deals with the continental drift theory movement of continents away from each other

It is believed that the continental drift led to the climate change

The mass extinction of 65 million years ago- Hypothesis 2

Two Particular Extinctions

This hypothesis deals with the volcanic activity in India

It is believed that this volcanic activity released particles into the air

These particles blocked out the sun for a long period of time

This resulted in the lowering of temperatures on Earth

Therefore many species died out because they could not adapt to the low temperature

The mass extinction of 65 million years ago ndash Hypothesis 3

Two Particular Extinctions

Scientists accept all three theories

Mass extinction was caused by climate change

The climate change was caused by the asteroid impact and volcanic activity

The mass extinction of 65 million years

The Holocene Epoch

The next major extinction is occurring presently

This is the sixth mass extinction

Human exploitation of the environment is the cause of this mass extinction

It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction

Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time

The sixth major extinction

Terminology

Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists

Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed

Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years

Jurassic Period period when dinosaurs flourished

Something for you to do

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

4 The first mass extinction was caused byhellip

A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above

5 The most famous extinction took placehellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and airB Water and airC Land and airD Water and land

9 Iridium ishellip

A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 3 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 4 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 5 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 6 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 7 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 7: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

The Five Major Mass Extinctions

The fifth mass extinction occurred about 65 million years ago

There are several possible causesbull asteroid impact on the Yucatan Peninsula which is in

the Gulf of Mexicobull gradual climate changebull volcanic eruptions

The fifth mass extinction

Two Particular Extinctions

Of the five mass extinctions two stand out

These were the one that occurred 250 million years ago and the one that occurred 65 million years ago

The mass extinction that occurred 250 million years ago was the most serious one

The most famous mass extinction occurred 65 million years ago the extinction of the dinosaurs

Two Particular Extinctions

During this extinction almost 90 all species became extinct

This included 84 of marine genera and about 70 of land species plants insects and vertebrate animals

The mass extinction of 250 million years ago

Two Particular Extinctions

The dinosaurs appeared about 245 million years ago

They flourished during the Jurassic Period

This period occurred about 208 to 143 million years ago

The dinosaurs dominated the land and air and some of them even lived in water

Two Particular Extinctions

Birds and mammals also existed during this time

The dinosaurs then became extinct in a short period of 10 million years

This occurred about 65 million years ago

Of the marine families 16 marine genera 47 and 18 of the land vertebrate families also became extinct during this time

The mass extinction of 65 million years ago

Two Particular Extinctions

Scientists are not sure about the exact cause of this mass extinction

However the following are some of the conditions that occurred during this timeo there was a sharp drop in temperatureo the water of the seas evaporates

The mass extinction of 65 million years - Causes

Two Particular Extinctions

Many of the plants the source of food for the dinosaurs died out

Iridium was found in a thin layer of clay

Iridium is an element that is very rare on earth but common in meteorites

A huge crater was found in the Caribbean Sea

There were many volcanic eruptions in India

The mass extinction of 65 million years - Causes

Two Particular Extinctions

The above evidence lead to the formation of three hypothesis

The most common hypothesis is that an asteroid crashed onto Earth causing global climate change

The climate change lead to the mass extinction

The layer of iridium and the large crater in the Caribbean sea support this hypothesis

The mass extinction of 65 million years ago - Hypothesis

Two Particular Extinctions

This hypothesis deals with the continental drift theory movement of continents away from each other

It is believed that the continental drift led to the climate change

The mass extinction of 65 million years ago- Hypothesis 2

Two Particular Extinctions

This hypothesis deals with the volcanic activity in India

It is believed that this volcanic activity released particles into the air

These particles blocked out the sun for a long period of time

This resulted in the lowering of temperatures on Earth

Therefore many species died out because they could not adapt to the low temperature

The mass extinction of 65 million years ago ndash Hypothesis 3

Two Particular Extinctions

Scientists accept all three theories

Mass extinction was caused by climate change

The climate change was caused by the asteroid impact and volcanic activity

The mass extinction of 65 million years

The Holocene Epoch

The next major extinction is occurring presently

This is the sixth mass extinction

Human exploitation of the environment is the cause of this mass extinction

It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction

Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time

The sixth major extinction

Terminology

Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists

Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed

Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years

Jurassic Period period when dinosaurs flourished

Something for you to do

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

4 The first mass extinction was caused byhellip

A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above

5 The most famous extinction took placehellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and airB Water and airC Land and airD Water and land

9 Iridium ishellip

A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 3 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 4 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 5 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 6 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 7 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 8: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Two Particular Extinctions

Of the five mass extinctions two stand out

These were the one that occurred 250 million years ago and the one that occurred 65 million years ago

The mass extinction that occurred 250 million years ago was the most serious one

The most famous mass extinction occurred 65 million years ago the extinction of the dinosaurs

Two Particular Extinctions

During this extinction almost 90 all species became extinct

This included 84 of marine genera and about 70 of land species plants insects and vertebrate animals

The mass extinction of 250 million years ago

Two Particular Extinctions

The dinosaurs appeared about 245 million years ago

They flourished during the Jurassic Period

This period occurred about 208 to 143 million years ago

The dinosaurs dominated the land and air and some of them even lived in water

Two Particular Extinctions

Birds and mammals also existed during this time

The dinosaurs then became extinct in a short period of 10 million years

This occurred about 65 million years ago

Of the marine families 16 marine genera 47 and 18 of the land vertebrate families also became extinct during this time

The mass extinction of 65 million years ago

Two Particular Extinctions

Scientists are not sure about the exact cause of this mass extinction

However the following are some of the conditions that occurred during this timeo there was a sharp drop in temperatureo the water of the seas evaporates

The mass extinction of 65 million years - Causes

Two Particular Extinctions

Many of the plants the source of food for the dinosaurs died out

Iridium was found in a thin layer of clay

Iridium is an element that is very rare on earth but common in meteorites

A huge crater was found in the Caribbean Sea

There were many volcanic eruptions in India

The mass extinction of 65 million years - Causes

Two Particular Extinctions

The above evidence lead to the formation of three hypothesis

The most common hypothesis is that an asteroid crashed onto Earth causing global climate change

The climate change lead to the mass extinction

The layer of iridium and the large crater in the Caribbean sea support this hypothesis

The mass extinction of 65 million years ago - Hypothesis

Two Particular Extinctions

This hypothesis deals with the continental drift theory movement of continents away from each other

It is believed that the continental drift led to the climate change

The mass extinction of 65 million years ago- Hypothesis 2

Two Particular Extinctions

This hypothesis deals with the volcanic activity in India

It is believed that this volcanic activity released particles into the air

These particles blocked out the sun for a long period of time

This resulted in the lowering of temperatures on Earth

Therefore many species died out because they could not adapt to the low temperature

The mass extinction of 65 million years ago ndash Hypothesis 3

Two Particular Extinctions

Scientists accept all three theories

Mass extinction was caused by climate change

The climate change was caused by the asteroid impact and volcanic activity

The mass extinction of 65 million years

The Holocene Epoch

The next major extinction is occurring presently

This is the sixth mass extinction

Human exploitation of the environment is the cause of this mass extinction

It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction

Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time

The sixth major extinction

Terminology

Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists

Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed

Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years

Jurassic Period period when dinosaurs flourished

Something for you to do

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

4 The first mass extinction was caused byhellip

A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above

5 The most famous extinction took placehellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and airB Water and airC Land and airD Water and land

9 Iridium ishellip

A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 3 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 4 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 5 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 6 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 9: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Two Particular Extinctions

During this extinction almost 90 all species became extinct

This included 84 of marine genera and about 70 of land species plants insects and vertebrate animals

The mass extinction of 250 million years ago

Two Particular Extinctions

The dinosaurs appeared about 245 million years ago

They flourished during the Jurassic Period

This period occurred about 208 to 143 million years ago

The dinosaurs dominated the land and air and some of them even lived in water

Two Particular Extinctions

Birds and mammals also existed during this time

The dinosaurs then became extinct in a short period of 10 million years

This occurred about 65 million years ago

Of the marine families 16 marine genera 47 and 18 of the land vertebrate families also became extinct during this time

The mass extinction of 65 million years ago

Two Particular Extinctions

Scientists are not sure about the exact cause of this mass extinction

However the following are some of the conditions that occurred during this timeo there was a sharp drop in temperatureo the water of the seas evaporates

The mass extinction of 65 million years - Causes

Two Particular Extinctions

Many of the plants the source of food for the dinosaurs died out

Iridium was found in a thin layer of clay

Iridium is an element that is very rare on earth but common in meteorites

A huge crater was found in the Caribbean Sea

There were many volcanic eruptions in India

The mass extinction of 65 million years - Causes

Two Particular Extinctions

The above evidence lead to the formation of three hypothesis

The most common hypothesis is that an asteroid crashed onto Earth causing global climate change

The climate change lead to the mass extinction

The layer of iridium and the large crater in the Caribbean sea support this hypothesis

The mass extinction of 65 million years ago - Hypothesis

Two Particular Extinctions

This hypothesis deals with the continental drift theory movement of continents away from each other

It is believed that the continental drift led to the climate change

The mass extinction of 65 million years ago- Hypothesis 2

Two Particular Extinctions

This hypothesis deals with the volcanic activity in India

It is believed that this volcanic activity released particles into the air

These particles blocked out the sun for a long period of time

This resulted in the lowering of temperatures on Earth

Therefore many species died out because they could not adapt to the low temperature

The mass extinction of 65 million years ago ndash Hypothesis 3

Two Particular Extinctions

Scientists accept all three theories

Mass extinction was caused by climate change

The climate change was caused by the asteroid impact and volcanic activity

The mass extinction of 65 million years

The Holocene Epoch

The next major extinction is occurring presently

This is the sixth mass extinction

Human exploitation of the environment is the cause of this mass extinction

It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction

Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time

The sixth major extinction

Terminology

Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists

Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed

Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years

Jurassic Period period when dinosaurs flourished

Something for you to do

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

4 The first mass extinction was caused byhellip

A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above

5 The most famous extinction took placehellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and airB Water and airC Land and airD Water and land

9 Iridium ishellip

A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 3 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 4 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 5 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 10: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Two Particular Extinctions

The dinosaurs appeared about 245 million years ago

They flourished during the Jurassic Period

This period occurred about 208 to 143 million years ago

The dinosaurs dominated the land and air and some of them even lived in water

Two Particular Extinctions

Birds and mammals also existed during this time

The dinosaurs then became extinct in a short period of 10 million years

This occurred about 65 million years ago

Of the marine families 16 marine genera 47 and 18 of the land vertebrate families also became extinct during this time

The mass extinction of 65 million years ago

Two Particular Extinctions

Scientists are not sure about the exact cause of this mass extinction

However the following are some of the conditions that occurred during this timeo there was a sharp drop in temperatureo the water of the seas evaporates

The mass extinction of 65 million years - Causes

Two Particular Extinctions

Many of the plants the source of food for the dinosaurs died out

Iridium was found in a thin layer of clay

Iridium is an element that is very rare on earth but common in meteorites

A huge crater was found in the Caribbean Sea

There were many volcanic eruptions in India

The mass extinction of 65 million years - Causes

Two Particular Extinctions

The above evidence lead to the formation of three hypothesis

The most common hypothesis is that an asteroid crashed onto Earth causing global climate change

The climate change lead to the mass extinction

The layer of iridium and the large crater in the Caribbean sea support this hypothesis

The mass extinction of 65 million years ago - Hypothesis

Two Particular Extinctions

This hypothesis deals with the continental drift theory movement of continents away from each other

It is believed that the continental drift led to the climate change

The mass extinction of 65 million years ago- Hypothesis 2

Two Particular Extinctions

This hypothesis deals with the volcanic activity in India

It is believed that this volcanic activity released particles into the air

These particles blocked out the sun for a long period of time

This resulted in the lowering of temperatures on Earth

Therefore many species died out because they could not adapt to the low temperature

The mass extinction of 65 million years ago ndash Hypothesis 3

Two Particular Extinctions

Scientists accept all three theories

Mass extinction was caused by climate change

The climate change was caused by the asteroid impact and volcanic activity

The mass extinction of 65 million years

The Holocene Epoch

The next major extinction is occurring presently

This is the sixth mass extinction

Human exploitation of the environment is the cause of this mass extinction

It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction

Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time

The sixth major extinction

Terminology

Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists

Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed

Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years

Jurassic Period period when dinosaurs flourished

Something for you to do

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

4 The first mass extinction was caused byhellip

A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above

5 The most famous extinction took placehellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and airB Water and airC Land and airD Water and land

9 Iridium ishellip

A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 11: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Two Particular Extinctions

Birds and mammals also existed during this time

The dinosaurs then became extinct in a short period of 10 million years

This occurred about 65 million years ago

Of the marine families 16 marine genera 47 and 18 of the land vertebrate families also became extinct during this time

The mass extinction of 65 million years ago

Two Particular Extinctions

Scientists are not sure about the exact cause of this mass extinction

However the following are some of the conditions that occurred during this timeo there was a sharp drop in temperatureo the water of the seas evaporates

The mass extinction of 65 million years - Causes

Two Particular Extinctions

Many of the plants the source of food for the dinosaurs died out

Iridium was found in a thin layer of clay

Iridium is an element that is very rare on earth but common in meteorites

A huge crater was found in the Caribbean Sea

There were many volcanic eruptions in India

The mass extinction of 65 million years - Causes

Two Particular Extinctions

The above evidence lead to the formation of three hypothesis

The most common hypothesis is that an asteroid crashed onto Earth causing global climate change

The climate change lead to the mass extinction

The layer of iridium and the large crater in the Caribbean sea support this hypothesis

The mass extinction of 65 million years ago - Hypothesis

Two Particular Extinctions

This hypothesis deals with the continental drift theory movement of continents away from each other

It is believed that the continental drift led to the climate change

The mass extinction of 65 million years ago- Hypothesis 2

Two Particular Extinctions

This hypothesis deals with the volcanic activity in India

It is believed that this volcanic activity released particles into the air

These particles blocked out the sun for a long period of time

This resulted in the lowering of temperatures on Earth

Therefore many species died out because they could not adapt to the low temperature

The mass extinction of 65 million years ago ndash Hypothesis 3

Two Particular Extinctions

Scientists accept all three theories

Mass extinction was caused by climate change

The climate change was caused by the asteroid impact and volcanic activity

The mass extinction of 65 million years

The Holocene Epoch

The next major extinction is occurring presently

This is the sixth mass extinction

Human exploitation of the environment is the cause of this mass extinction

It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction

Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time

The sixth major extinction

Terminology

Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists

Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed

Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years

Jurassic Period period when dinosaurs flourished

Something for you to do

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

4 The first mass extinction was caused byhellip

A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above

5 The most famous extinction took placehellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and airB Water and airC Land and airD Water and land

9 Iridium ishellip

A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 3 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 4 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 5 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 6 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 12: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Two Particular Extinctions

Scientists are not sure about the exact cause of this mass extinction

However the following are some of the conditions that occurred during this timeo there was a sharp drop in temperatureo the water of the seas evaporates

The mass extinction of 65 million years - Causes

Two Particular Extinctions

Many of the plants the source of food for the dinosaurs died out

Iridium was found in a thin layer of clay

Iridium is an element that is very rare on earth but common in meteorites

A huge crater was found in the Caribbean Sea

There were many volcanic eruptions in India

The mass extinction of 65 million years - Causes

Two Particular Extinctions

The above evidence lead to the formation of three hypothesis

The most common hypothesis is that an asteroid crashed onto Earth causing global climate change

The climate change lead to the mass extinction

The layer of iridium and the large crater in the Caribbean sea support this hypothesis

The mass extinction of 65 million years ago - Hypothesis

Two Particular Extinctions

This hypothesis deals with the continental drift theory movement of continents away from each other

It is believed that the continental drift led to the climate change

The mass extinction of 65 million years ago- Hypothesis 2

Two Particular Extinctions

This hypothesis deals with the volcanic activity in India

It is believed that this volcanic activity released particles into the air

These particles blocked out the sun for a long period of time

This resulted in the lowering of temperatures on Earth

Therefore many species died out because they could not adapt to the low temperature

The mass extinction of 65 million years ago ndash Hypothesis 3

Two Particular Extinctions

Scientists accept all three theories

Mass extinction was caused by climate change

The climate change was caused by the asteroid impact and volcanic activity

The mass extinction of 65 million years

The Holocene Epoch

The next major extinction is occurring presently

This is the sixth mass extinction

Human exploitation of the environment is the cause of this mass extinction

It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction

Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time

The sixth major extinction

Terminology

Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists

Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed

Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years

Jurassic Period period when dinosaurs flourished

Something for you to do

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

4 The first mass extinction was caused byhellip

A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above

5 The most famous extinction took placehellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and airB Water and airC Land and airD Water and land

9 Iridium ishellip

A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 3 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 4 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 5 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 6 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 7 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 13: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Two Particular Extinctions

Many of the plants the source of food for the dinosaurs died out

Iridium was found in a thin layer of clay

Iridium is an element that is very rare on earth but common in meteorites

A huge crater was found in the Caribbean Sea

There were many volcanic eruptions in India

The mass extinction of 65 million years - Causes

Two Particular Extinctions

The above evidence lead to the formation of three hypothesis

The most common hypothesis is that an asteroid crashed onto Earth causing global climate change

The climate change lead to the mass extinction

The layer of iridium and the large crater in the Caribbean sea support this hypothesis

The mass extinction of 65 million years ago - Hypothesis

Two Particular Extinctions

This hypothesis deals with the continental drift theory movement of continents away from each other

It is believed that the continental drift led to the climate change

The mass extinction of 65 million years ago- Hypothesis 2

Two Particular Extinctions

This hypothesis deals with the volcanic activity in India

It is believed that this volcanic activity released particles into the air

These particles blocked out the sun for a long period of time

This resulted in the lowering of temperatures on Earth

Therefore many species died out because they could not adapt to the low temperature

The mass extinction of 65 million years ago ndash Hypothesis 3

Two Particular Extinctions

Scientists accept all three theories

Mass extinction was caused by climate change

The climate change was caused by the asteroid impact and volcanic activity

The mass extinction of 65 million years

The Holocene Epoch

The next major extinction is occurring presently

This is the sixth mass extinction

Human exploitation of the environment is the cause of this mass extinction

It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction

Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time

The sixth major extinction

Terminology

Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists

Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed

Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years

Jurassic Period period when dinosaurs flourished

Something for you to do

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

4 The first mass extinction was caused byhellip

A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above

5 The most famous extinction took placehellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and airB Water and airC Land and airD Water and land

9 Iridium ishellip

A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 3 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 4 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 5 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 6 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 7 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 14: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Two Particular Extinctions

The above evidence lead to the formation of three hypothesis

The most common hypothesis is that an asteroid crashed onto Earth causing global climate change

The climate change lead to the mass extinction

The layer of iridium and the large crater in the Caribbean sea support this hypothesis

The mass extinction of 65 million years ago - Hypothesis

Two Particular Extinctions

This hypothesis deals with the continental drift theory movement of continents away from each other

It is believed that the continental drift led to the climate change

The mass extinction of 65 million years ago- Hypothesis 2

Two Particular Extinctions

This hypothesis deals with the volcanic activity in India

It is believed that this volcanic activity released particles into the air

These particles blocked out the sun for a long period of time

This resulted in the lowering of temperatures on Earth

Therefore many species died out because they could not adapt to the low temperature

The mass extinction of 65 million years ago ndash Hypothesis 3

Two Particular Extinctions

Scientists accept all three theories

Mass extinction was caused by climate change

The climate change was caused by the asteroid impact and volcanic activity

The mass extinction of 65 million years

The Holocene Epoch

The next major extinction is occurring presently

This is the sixth mass extinction

Human exploitation of the environment is the cause of this mass extinction

It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction

Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time

The sixth major extinction

Terminology

Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists

Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed

Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years

Jurassic Period period when dinosaurs flourished

Something for you to do

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

4 The first mass extinction was caused byhellip

A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above

5 The most famous extinction took placehellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and airB Water and airC Land and airD Water and land

9 Iridium ishellip

A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 3 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 4 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 5 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 6 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 15: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Two Particular Extinctions

This hypothesis deals with the continental drift theory movement of continents away from each other

It is believed that the continental drift led to the climate change

The mass extinction of 65 million years ago- Hypothesis 2

Two Particular Extinctions

This hypothesis deals with the volcanic activity in India

It is believed that this volcanic activity released particles into the air

These particles blocked out the sun for a long period of time

This resulted in the lowering of temperatures on Earth

Therefore many species died out because they could not adapt to the low temperature

The mass extinction of 65 million years ago ndash Hypothesis 3

Two Particular Extinctions

Scientists accept all three theories

Mass extinction was caused by climate change

The climate change was caused by the asteroid impact and volcanic activity

The mass extinction of 65 million years

The Holocene Epoch

The next major extinction is occurring presently

This is the sixth mass extinction

Human exploitation of the environment is the cause of this mass extinction

It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction

Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time

The sixth major extinction

Terminology

Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists

Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed

Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years

Jurassic Period period when dinosaurs flourished

Something for you to do

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

4 The first mass extinction was caused byhellip

A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above

5 The most famous extinction took placehellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and airB Water and airC Land and airD Water and land

9 Iridium ishellip

A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 16: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Two Particular Extinctions

This hypothesis deals with the volcanic activity in India

It is believed that this volcanic activity released particles into the air

These particles blocked out the sun for a long period of time

This resulted in the lowering of temperatures on Earth

Therefore many species died out because they could not adapt to the low temperature

The mass extinction of 65 million years ago ndash Hypothesis 3

Two Particular Extinctions

Scientists accept all three theories

Mass extinction was caused by climate change

The climate change was caused by the asteroid impact and volcanic activity

The mass extinction of 65 million years

The Holocene Epoch

The next major extinction is occurring presently

This is the sixth mass extinction

Human exploitation of the environment is the cause of this mass extinction

It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction

Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time

The sixth major extinction

Terminology

Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists

Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed

Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years

Jurassic Period period when dinosaurs flourished

Something for you to do

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

4 The first mass extinction was caused byhellip

A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above

5 The most famous extinction took placehellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and airB Water and airC Land and airD Water and land

9 Iridium ishellip

A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 3 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 4 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 5 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 17: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Two Particular Extinctions

Scientists accept all three theories

Mass extinction was caused by climate change

The climate change was caused by the asteroid impact and volcanic activity

The mass extinction of 65 million years

The Holocene Epoch

The next major extinction is occurring presently

This is the sixth mass extinction

Human exploitation of the environment is the cause of this mass extinction

It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction

Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time

The sixth major extinction

Terminology

Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists

Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed

Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years

Jurassic Period period when dinosaurs flourished

Something for you to do

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

4 The first mass extinction was caused byhellip

A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above

5 The most famous extinction took placehellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and airB Water and airC Land and airD Water and land

9 Iridium ishellip

A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 3 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 4 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 5 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 6 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 7 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 18: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

The Holocene Epoch

The next major extinction is occurring presently

This is the sixth mass extinction

Human exploitation of the environment is the cause of this mass extinction

It is occurring in the Holocene Epoch and the mass extinction is called the Holocene extinction or sometimes the megafauna extinction

Reason why it is called the megafauna extinction the large mammals ( woolly mammoth and dodo) became extinct during this time

The sixth major extinction

Terminology

Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists

Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed

Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years

Jurassic Period period when dinosaurs flourished

Something for you to do

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

4 The first mass extinction was caused byhellip

A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above

5 The most famous extinction took placehellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and airB Water and airC Land and airD Water and land

9 Iridium ishellip

A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 3 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 4 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 5 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 6 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 7 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 19: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Terminology

Extinction refers to the death of all the organisms of a species so that not even a single member of the species exists

Natural extinctions usually occur at a constantly lower rate almost the same rate at rate at which new species are formed

Mass extinction when more than 50 of the earthrsquos species vanishes in a geological instant of a few million years

Jurassic Period period when dinosaurs flourished

Something for you to do

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

4 The first mass extinction was caused byhellip

A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above

5 The most famous extinction took placehellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and airB Water and airC Land and airD Water and land

9 Iridium ishellip

A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 3 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 4 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 5 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 6 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 7 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 20: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Something for you to do

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

4 The first mass extinction was caused byhellip

A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above

5 The most famous extinction took placehellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and airB Water and airC Land and airD Water and land

9 Iridium ishellip

A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 3 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 4 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 5 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 6 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 21: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million years

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

4 The first mass extinction was caused byhellip

A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above

5 The most famous extinction took placehellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and airB Water and airC Land and airD Water and land

9 Iridium ishellip

A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 3 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 4 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 5 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 6 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 7 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 22: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

3 The name given to the extinction characterized by the death of large mammals

A Mass extinctionB ExtinctionC Megafauna extinctionD None of the above

4 The first mass extinction was caused byhellip

A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above

5 The most famous extinction took placehellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and airB Water and airC Land and airD Water and land

9 Iridium ishellip

A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 3 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 4 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 5 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 6 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 7 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 23: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

4 The first mass extinction was caused byhellip

A Drop in sea levelsB Formation of glaciersC Rising sea levels as the glaciers meltedD All of the above

5 The most famous extinction took placehellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and airB Water and airC Land and airD Water and land

9 Iridium ishellip

A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 3 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 4 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 5 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 6 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 7 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 24: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

5 The most famous extinction took placehellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and airB Water and airC Land and airD Water and land

9 Iridium ishellip

A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 3 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 4 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 25: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and airB Water and airC Land and airD Water and land

9 Iridium ishellip

A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 3 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 4 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 5 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 6 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 7 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 26: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

7 The most serious mass extinction took places more thanhellip

A 65 million years agoB 250 million years agoC 364 million years agoD 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and airB Water and airC Land and airD Water and land

9 Iridium ishellip

A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 3 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 4 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 5 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 27: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

8 Dinosaurs dominated thehellip

A Water land and airB Water and airC Land and airD Water and land

9 Iridium ishellip

A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 3 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 28: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

9 Iridium ishellip

A A rare element found in asteroidsB Found in the dinosaursC A type of dinosaurD The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 3 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 4 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 5 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 6 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 7 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 29: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinctionB first mass extinctionC second mass extinctionD fifth mass extinction

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 3 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 4 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 5 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 6 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 7 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 30: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Solution

1 B

2 A

3 C

4 D

5 A

6 C

7 B

8 D

9 A

10 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 3 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 4 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 5 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 6 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 7 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 31: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 1 of 15

Mass extinctions

A mass extinction is a sharp decrease in the amount of plant and animal life There have been five major

mass extinction events in Earths history

These are shown in the table given along with the major events that characterised each

Learn about the five major mass extinctions that occurred in Earths history

Video 2CY4

Five of the following extinction events are recognised (listed from the most recent at top of the list to the

earliest oldest at bottom of list

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

bull End-Triassic

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull Late Devonian

bull Late Ordovician

Major mass extinction event

Date of occurrence

Major events

Cretaceous-Paleogene extinction event

65 million years ago

Approximately 75 of all species became extinct Mammals and birds emerged as the dominant land vertebrates

Triassic-Jurassic event

205 million years ago

Most non-dinosaur species were eliminated leaving land dinosaurs with no competition

Permian-Triassic event

250 million years ago

This was Earths largest extinction event It resulted in the loss of 96 of marine species and 70 of land species The event had great evolutionary significance because it allowed the vacant habitats and ecosystems to be filled by new species through natural selection

Late Devonian extinction

375ndash360 million years ago

This was a prolonged period of extinction lasting up to 20 million years During this period up to 70 of living species were eliminated

Ordovician-Silurian extinction event

450ndash440 million years ago

Over 50 of all genera were eliminated during this period and is ranked as the second largest mass extinction in Earths history

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 3 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 4 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 5 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 6 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 7 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 32: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 2 of 15

Causes of mass extinctions (ESGCW)

Watch a video about the debate about what really killed the dinosaurs

Video 2CY6

There is still a lot of debate among scientists as to what caused the mass extinctions To be a valid theory

to explain what caused mass extinctions the theory must

bull Explain all the losses of species at a particular mass extinction event (not just specific losses eg

dinosaurs)

bull Explain why some organisms died and others survived

bull Be based on natural events and processes that are shown to have occurred around the time of

extinction

Two of the hypotheses put forward are

bull the impact theory of extinction

bull massive volcanic activity

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 3 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 4 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 5 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 6 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 7 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 33: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 4 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 34: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 5 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 35: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 5 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 6 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

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Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 36: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 6 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 7 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 37: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 7 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 38: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 8 of 15

Other resources

httpswwwdailymailcouksciencetecharticle-5692167Interactive-map-lets-

travel-time-planet-600-million-years-historyhtml

httpswwwamnhorglearn-teachcurriculum-collections

httpswwwsiyavulacomreadsciencegrade-10-lifescienceshistory-of-life-on-

earth10-history-of-life-on-earth-04

httpswwwnationalgeographiccomscienceprehistoric-worldmass-extinction

httpsphysorgnews2015-11-elementary-theory-mass-extinctions-lifehtml

httpswwwyoutubecomwatchv=bU1QPtOZQZU

httpyoutubecomwatchv=FlUes_NPa6M

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 39: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 9 of 15

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 40: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 10 of 15

Activity 1

The diagram below represents a simplified geological time-scale showing how the number of families

(groups of related species) has changed over a period of time

11 How many mass extinctions took place since the creation of the earth (1)

12 Which mass extinction took place towards the end of the Palaeozoic era (1)

13 Which era had the longest duration (1)

14 Name TWO factors or events known to have caused mass extinctions (2)

15 When did the Triassic extinction take place (1)

16 Which extinction was the biggest in terms of the number of families that went extinct (1)

17 Scientists believe that we are currently experiencing the sixth mass extinction What is thought to be

the cause of this mass extinction (1)

18 What evidence do scientists put forth today to support the idea that we are entering the sixth

extinction (2)

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 41: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 11 of 15

19 Do you tend to believe the prediction that in the decades ahead we may witness an extinction event

on par with those last seen millions of years ago Explain (5)

Activity 2

1 The process by which living organism die off so that not a single member of the species exists

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

2 The disappearance of more than 50 of the Earthrsquos species in a geological instant of a few million

years

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

3 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

4 The name given to the extinction characterized by the death of large mammals

A Mass extinction

B Extinction

C Megafauna extinction

D None of the above

5 The most famous extinction took placehellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 42: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 12 of 15

6 The mass extinction that occurred as a result of unknown causes is occurred more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

7 The most serious mass extinction took places more thanhellip

A 65 million years ago

B 250 million years ago

C 364 million years ago

D 439 million years ago

8 Dinosaurs dominated thehellip

A Water land and air

B Water and air

C Land and air

D Water and land

9 Iridium ishellip

A A rare element found in asteroids

B Found in the dinosaurs

C A type of dinosaur

D The sixth mass extinction

10 The highest rate of mass extinction occurs during thehellip

A sixth mass extinction

B first mass extinction

C second mass extinction

D fifth mass extinction

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 43: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 13 of 15

Activity 3

Write paragraph type of answers on each of the following extinction events

bull Late Ordovician

bull Late Devonian

bull End-Permian (sometimes called ldquoPermian-Triassicrdquo)

bull End-Triassic

bull End-Cretaceous (also known as ldquoCretaceous-Tertiaryrdquo or ldquoK-Trdquo)

Guiding questions for research

1 When did this extinction take place

2 Describe the extent of the extinction

21 How many kinds of organisms lived on Earth before the extinction

22 What percentages were lost during the extinction

23 Did new kinds of organisms evolve after this extinction

3 What did Earth look like at that time

4 Were the continents in the same locations they are in today If not how were they arranged

5 How do scientists know what they know about the event

6 What evidence have they used to support their ideas

7 Name some of the kinds of organisms that went extinct during the extinction

8 What explanations have scientists put forth to explain why so many groups of organisms disappeared

during this extinction

9 Do scientists agree on the cause for this extinction

Name of extinction event

Criteria Description

1 Date

2 Reason for the

mass extinction

3 Number of

genera and

percentage

before the

extinction

events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 44: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 14 of 15

4 Number of

genera and

percentage

after the

extinction event

5 New genera

that evolved

after this

extinction

6 Name some

kinds of

organisms that

went extinct

during this

extinction

7 What evidence

is there to

support the

explanation of

how the

extinction

happened

8 What did earth

look like when

this extinction

took place

(what

continents were

there at the

time)

9 Diagrams of

organisms that

went extinct

during this

extinction

event

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 45: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 2 amp 3

Page 15 of 15

Recap lesson What commonalities do you see among these extinctions What differences do you

see among these extinctions

Additional requirements (not compulsory)

bull The years the extinction event took place

bull A drawing or other visual representation of three species that went extinct during their event

bull A map showing the location and names of the continents at that time

bull A pie chart or other graphics indicating the percentage of life on Earth that went extinct at that time

bull Two facts about this extinction event that make it significant in the history of life on Earth (significant

life forms that went extinct new life forms that evolved

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 46: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

History of Life on Earth Fossils

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 47: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Agenda or Summary LayoutA summary of the presentation

1

2

3

4

Discussion Item OneWhat are fossils

Discussion Item TwoFormation of Fossils

Discussion Item ThreeDetermining the age of the fossils

Discussion Item FourEvidence for the key events in the history of life

5

6

Discussion Item FiveHuman Impact on Biodiversity and Natural Environment

Discussion Item SixFossil tourism

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 48: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

What are Fossils

Fossils are remains of ancient life forms preserved in rock

They may also occur in ice tar and dried sap of trees

The study of fossils is called paleontology

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 49: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Formation of Fossils

The richest sources of fossils are found in sedimentary rock

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom

The mineral salts also settle to the bottom

The mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 50: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Formation of Fossils

An imprint is left behind when the organism starts to decay before it becomes petrified

Therefore some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or imprintsImprints are just outlines of the dead organism or parts of it left in the stone

Imprints

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 51: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Formation of Fossils

The sedimentary rock pile up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

Sedimentary Rock

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 52: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Formation of Fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

This means that they are found in a large number of places

Index fossils

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 53: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Formation of Fossils

Some examples of fossils arehellip

bones of vertebrates shellsexoskeletons of invertebrates tracks(footprints) burrows and hardened faeces of

animals petrified tree trunks imprints of leaves and small animals

Examples of Fossils

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 54: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Formation of Fossils

Remember fossils also occur in tar and ice

Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber

Amber is the hardened form of liquid sap of plants

Examples of Fossils

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 55: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Determining the Age of Fossils

There are two methods used to determine the age of fossils

These are relative dating and radiometric dating

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 56: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Determining the Age of Fossils

In relative dating the age of the fossil is worked by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossilAn example of geological event is an volcanic eruption

Relative dating

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 57: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Determining the Age of Fossils

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

Relative dating

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 58: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Determining the Age of Fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

Relative dating

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 59: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Determining the Age of Fossils

Radiometric dating tries to find out how long ago a particular fossil was

formed

Radiometric dating means radio comes from the word radioactive

Radioactive is used to describe substances that give off nuclear radiation

Nuclear radiation is very useful because radioactive substances decay at a

fixed rate

This means that they lose their radioactivity at a fixed rate

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radiometric Dating

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 60: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Determining the Age of Fossils

1 Living organisms contain carbon -12 and carbon -142 Carbon -14 is radioactive3 When the organism dies the carbon -14 becomes

nitrogen-144 Carbon-14 turns to nitrogen-14 at a fixed rate5 Scientists are able to work out the age of the fossil

by comparing the ratio of carbon -14 to total carbon and nitrogen-14

Radiometric dating ndash the process

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 61: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Determining the Age of Fossils

Both methods are used to determine the age of the fossilFor exampleIf a volcanic eruption occurred then radiometric dating can be used to determine when the eruption occurred

Relative dating can be used to compare the fossils with the dateof the eruption

If the fossil is found in the layer above the volcanic ash then it was formed after the eruption

If it is formed in the layer below the ash then it formed before the eruption

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 62: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Key Events in Southern Africa

One of the oldest evidence of life on Earth is found in Barberton in Mpumalanga

These are fossilized photosynthetic bacteria cells

These fossil are about 3400 million years old

The bacteria had jelly like substance around it

Fine rock particles became attached to the jelly like substance this forces the bacteria to grow upward to search for light

This results in the formation of a structure called stromatolites

Fossil Evidence

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 63: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Key Events in Southern Africa

These are dome-shaped mat like layers of rock

Stromatolites

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 64: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Key Events in Southern Africa

The oldest known multi cellular organism is found in Namibia

The multi-cellular organisms are sponges called Otavia

They are found in limestone rocks found in northern Namibia

These fossilized sponges are thought to be 650 million years old

A similar type of fossil and fossils of other soft body invertebrates have been found in North Cape

Oldest fossil of multi-cellular organism

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 65: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Key Events in Southern Africa

Fossils of algae and early land plants have been found in the Eastern Cape near Grahamstown

These fossils are about 350 million years old

A nearly 280 million year old fossil of cone bearing plants have been found near Mooi River and Escourt in Kwa Zulu Natal

A picture of Glossopterisfossil

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 66: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

These fossils are called Glossopteris These Glossopteris occupied Gondwanaland for almost 60 million years These plants were responsible for the coal deposits found in Southern Africa

The picture is a reconstruction of what the Glossopteris may have looked like

Key Events in Southern AfricaGlossopteris

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 67: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Map showing Coal Deposits in South Africa

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 68: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Fossils of reptiles such as Lystrosaurus and Thrinaxodon have been found in the Karoo

Key Events in Southern AfricaReptiles

These reptiles were believed to give rise to mammals

They lived between 280 and 100 million years ago

Lystrosaurus

Thrinaxodon

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 69: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Key Events in Southern Africa

Dinosaurs lived 210 million years ago in Lesotho north-eastern Free State Kwa Zulu Natal and the north eastern parts of Eastern Cape

This is supported by findings of fossilized footprints of dinosaurs in these areas

Fossilized dinosaur bones have been found in Maluti and Drakensberg mountain ranges

Dinosaurs

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 70: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Euskelosarus was a very early dinosaur

It was a herbivore

The first fossils of the skulland skeleton were found near Ladybrand in the Eastern Free State

Euskelosarus

Key Events in Southern AfricaDinosaurs

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 71: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Key Events in Southern Africa

There is evidence of early mammals in Southern Africa

This is a shrew-sized mammal found in the Eastern Cape Province and Lesotho

The caves of the Cradle of Humankind contains most of the fossil evidence of early humans

Evidence of human existence can also be found in the Free State Kwa Zulu Natal and Eastern Cape

This evidence is in the form of fossils and artefacts

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 72: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

The diagram shows a example of a Coelacanths

Some of their fins are lobe like

This and many other features have led scientists to believe that they are more closely related to amphibians than fish

Coelacanths were thought to have become extinct about 70 million years ago

However in 1938 a living coelacanth was caught of the coast of East London

A population of about 15 coelacanths have been found near Sodwana Bay

Coelacanths are also called the living fossil

Key Events in Southern AfricaCoelacanths

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 73: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Human Impact on Biodiversity and the Natural

Environment

Some of the treats are listed below

1 Habitat destruction

2 Natural disasters

3 Over-exploitation

4 Pollution

5 Pesticides and fertilizers

6 Climate change

7 Alien invasive species

8 Disease

Threats to Biodiversity and the Natural Environment

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 74: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Fossil tourism

Fossil tourism is a type of ecotourism but in fossil tourism the main attraction is its fossils

One of the most famous fossils sites is the Cradle of Humankind

The Cradle of Humankind is found in Gauteng and North West Province

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 75: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Fossil tourism

Found in Sterkfontein Swartkrans Kromdraai regionsIt is a World Heritage Site since 1999

It is one of the richest source of fossils of early humans

Nearly half of all human-ancestor fossils have been found here

Cradle of Humankind

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 76: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Fossil tourism

The West Coast Fossil Park is found in the Western Cape Province

It is found along the west coast a few kilometers inland of the Langebaan Lagoon

This was once a phosphate mine

It has the greatest diversity of five million old fossils

It contained the fossils of the first bear ever found south of the Sahara

Fossils of the extinct true seal and four extinct species of penguins were found here

West Coast Fossil Park

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 77: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Fossil tourism

The many hand on activities at the park that makes it very exciting for the tourist

Tourists can sift in the sand looking for fossils with the promise that if you find something new ( no one has found) then it will be named after you

Plans have been put into place to start a national fossil and rock art route that joins the Fossil Park to the Cradle

West Coast Fossil Park

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 78: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Fossil tourism

Important fossils have been moved to museums once they have been discovered

The dinosaur fossil found in the Karoo have been moved to the museum in Graaff-Reinet

The museums become important fossil tourist attractions

Museums

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 79: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Fossil tourism

Fossil tourism

1 Creates jobs

2 Generates income for people living in these areas

3 Creates business opportunities for travel agents

and tour operators

Advantages of Fossil Tourism

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 80: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Terminology

Fossils are remains of ancient life forms preserved in rock

Paleontology is the study of fossils

Petrify this means to turn into stone

Imprints are left behind when the organisms start to decay before it becomes petrified

Strata are the in layers in which sedimentary rock pile up

Index fossils are fossils which have occurred in a particular period of time and then can be used to determine the age of other fossils by comparison with them

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 81: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Terminology

Amber is the hardened form of liquid sap

Relative dating finds the age of the fossil by comparing it to another fossil or geological event

Radiometric dating tries to find out how long ago a particular fossil was formed

Stromatolites are dome-shaped mat like layers of rock

Fossil tourism is a type of ecotourism where the main attraction is its fossils

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 82: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Something for your to do

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A AmberB TarC SappedD Ice

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 83: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative datingB PaleontologyC TimingD Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 84: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative datingB PaleontologyC TimingD Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 85: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A RelativeB RadioactiveC RadiometricD Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 86: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

5 The group name given to the first life forms which developed on Earth about 38 billion years ago ishellip

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 87: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

6 The strange looking fish once thought to be extinct over 70 million years ago

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 88: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

7 Cone bearing plants that were responsible for the formation of the coal deposits in southern Africa

A CoelacanthB GlossopterisC Photosynthetic bacteriaD Euskelosaurus

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 89: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

8 The skull and skeleton of the Euskelosaurus is found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 90: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

9 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 91: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

10 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 92: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

11 The fossils of soft bodied invertebrates have been found inhellip

A LadybrandB BarbertonC Northern CapeD Eastern Cape

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 93: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

12 The fossils of the most primitive mammal like reptiles were found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 94: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

13 Dinosaur bones were located inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 95: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

14 The worldrsquos richest concentration of fossils occur inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 96: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

15 The fossils of 650 million year old sponges have been found inhellip

A MalutiB KarooC Northern NamibiaD Western Cape

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 97: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

16 Early dinosaur found in Ladybrand that was a herbivore

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 98: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

17 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 99: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

18 A reptile that gave rise to mammals

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 100: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

19 Cone bearing plant found in Mooi River nearly 280 million years ago

A LystrosaurusB GlossopterisC EuskelosaurusD Octavia

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 101: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

20 World heritage sitehellip

A Cradle of HumankindB West Coast Fossil ParkC Mooi RiverD Durban

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 102: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Solution

1 A

2 D

3 A

4 B

5 C

6 A

7 B

8 A

9 D

10 B

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 103: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Solution

11 C

12 B

13 A

14 D

15 C

16 C

17 D

18 A

19 B

20 A

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 104: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 1 of 12

Fossil formation and methods of dating

1 What are fossils

Fossils are the mineralized remains of animals or plants or other traces such as footprints

All of the fossils and their placement in rock formations and sedimentary layers (strata) are known as the

fossil record

The study of fossils is called palaeontology

The richest sources of fossils are found in sedimentary rock

2 How are fossils formed

The following sets of diagrams and annotations (notes) explain how fossils form

The organism (ammonite in this example) dies

Sand and silt from the land is carried to the seas and swamps by rivers

The remains of dead organisms settle to the bottom of the river swamp ocean floor

An imprint is left behind in the sediment when the organism starts to decay before it becomes petrified

Imprints are just outlines of the dead organism or parts of it left in the stone

Numerous mineral salts also settle to the bottom of the river swamp ocean floor

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 105: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 2 of 12

The soft parts of the organismrsquos body decays leaving only the shell or other hard parts of the body eg

skeleton

These mineral salts then filter into the body of the dead organism

The organism becomes petrified this means that it turns into stone

Some fossils are actual organisms or parts of the dead organism while other fossils are just impressions or

imprints left behind

3 Sedimentary rock

The sedimentary rock piles up over each other over millions of years

They pile up in layers called strata

The oldest layer is at the bottom and the youngest layer at the top

Certain fossils were found in certain layers

This means that these fossils were formed in a particular period of time

4 What are Index fossils

Index fossils give an indication of the time period in which they were formed

The index fossils have a wide geographic distribution

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 106: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 3 of 12

This means that they are found in a large number of places

5 Examples of fossils

bull bones of vertebrates

bull shells exoskeletons of invertebrates

bull tracks (footprints)

bull burrows

bull hardened faeces of animals

bull petrified tree trunks

bull imprints of leaves and small animals

Different forms or types of fossils

ammonite fossils

Petrified cone of Araucaria sp from

Patagonia Argentina dating from

the Jurassic Period (approx 210 Ma)

Eocene fossil fish Priscacara liops Petrified wood

from Green River Formation of Utah

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 107: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 4 of 12

Lower Proterozoic Stromatolites from Bolivia

South America

Earthrsquos oldest fossils are the stromatolites Fossil shrimp (Cretaceous)consisting of rock built from layer upon layer

of sediment and other precipitants[3]

A fossil gastropod from the Pliocene of Cyprus

A serpulid worm is attached

Megalodon and Carcharodontosaurus teeth The latter

was found in the Sahara Desert

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 108: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 5 of 12

Permineralization

External mold of a bivalve from the

Logan Formation Lower Carboniferous Ohio

Recrystallized scleractinian coral

(aragonite to calcite) from the Jurassic of southern Israel

Resin fossils

Leptofoenus pittfieldae trapped in Dominican

amber from 20-16 million years ago

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 109: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 6 of 12

Skeleton of whale that walked on land found in Pakistan

6 Other types of fossils

Remember fossils also occur in tar and ice Here are some examples of such fossilshellip

fossils of the woolly mammoth were found frozen in ice

pits of tar contained bones of the sabre toothed cats

some insects have been found in amber Amber is the hardened form of liquid sap of plants

Generally five types of fossils are recognised

bull Mould fossil

bull Cast fossil

bull Trace fossil

bull True form fossil

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 110: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 7 of 12

7 Determining the age of fossils

There are two methods used to determine the age of fossils

These are

relative dating and

radiometric dating

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 111: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 8 of 12

8 Relative dating

In relative dating the age of the fossil is calculated by comparing it to another fossil or geological event

Relative dating is able to tell us whether a fossil is formed before or after another fossil or geological event

It does not give the exact age of the fossil

An example of geological event is a volcanic eruption

If the original stratification or layering in a rock is undisturbed scientists can tell that a fossil in a lower layer

was formed before the one found in the upper layer

This does not tell us the exact age of the fossil

If the original layering is upset it is not so easy to compare the age of one fossil to another

Scientists are able to use index fossils

If a new fossil and an index fossil is found in the upper most layer of rock then scientists can tell

the rock actually came from a lower layer

the original layering was upset by a geological event

the new fossil was formed before the other fossils

9 Radiometric dating

Radiometric dating tries to find out how long ago a particular fossil was formed It is more reliable and

accurate than the Relative dating method

Radiometric dating means

radio comes from the word radioactive

Metric simply refers to measurement

Dating refers to the process of finding out the age of the fossil

Radioactive is used to describe substances that give off nuclear radiation Nuclear radiation is very useful

because radioactive substances decay at a fixed rate This means that an atom lose their radioactivity at a

fixed rate

Activity 4

1 The solid formed from the hardening of the liquid sap of trees is calledhellip

A Amber

B Tar

C Sapped

D Ice

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 112: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 9 of 12

2 The process of finding out the ages of rocks and fossils using radioactive elements ishellip

A Relative dating

B Paleontology

C Timing

D Radiometric dating

3 The process of finding out the ages of fossils by comparison with another fossil or rock

A Relative dating

B Paleontology

C Timing

D Radiometric dating

4 Substances which give of nuclear radiation and decay into other substances are calledhellip

A Relative

B Radioactive

C Radiometric

D Reactive

5 The group name given to the first life forms which developed on Earth about 38 billion years ago

ishellip

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

6 The strange looking fish once thought to be extinct over 70 million years ago

A Coelacanth

B Glossopteris

C Photosynthetic bacteria

D Euskelosaurus

7 A skull and skeleton of the Euskelosaurus was found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 113: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 10 of 12

8 The 359 million year old fossils of algae and early land plants such as club mosses are located inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 114: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 11 of 12

9 Fossilized photosynthetic bacterial cells which are 3 400 million years old are found inhellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

10 Fossils of soft bodied invertebrates have been found in or near hellip

A Ladybrand

B Barberton

C Northern Cape

D Eastern Cape

11 The fossils of the most primitive mammal like reptiles were found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

12 Dinosaur bones were located in or nearhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

13 The worldrsquos richest concentration of fossils occurs inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

14 Fossils of 650 million year old sponges have been found inhellip

A Maluti

B Karoo

C Northern Namibia

D Western Cape

15 Name of an early dinosaur found in Ladybrand that was a herbivore

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban

Page 115: History of life on Earthintervention.roodie.co.za/assets/files/Gr10LSWeek36.pdf · • Late Devonian • Late Ordovician Major mass extinction event Date of occurrence Major events

Recovery Programme Life Sciences Gr 10 History of life on Earth Week 36 Lesson 4 amp 5

Page 12 of 12

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

16 Name given to sponges found in the limestone rocks of northern Namibia 650 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

17 A reptile that gave rise to mammals

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

18 Cone bearing plant found in Mooi River nearly 280 million years ago

A Lystrosaurus

B Glossopteris

C Euskelosaurus

D Octavia

19 This area has been declared a World heritage sitehellip

A Cradle of Humankind

B West Coast Fossil Park

C Mooi River

D Durban