EVOLUTION BY MEANS OF NATURAL

SELECTIONCh. 10 & 15

1. What adaptations does this organism have?2. How did these adaptations evolve?3. How do they enable the organism to survive in its environment?

1. What adaptations does this organism have?2. How did these adaptations evolve?3. How do they enable the organism to survive in its environment?

1. What adaptations does this organism have?2. How did these adaptations evolve?3. How do they enable the organism to survive in its environment?

They have long legs and neck, long, tough, prehensile tongue, and leathery mouth for food gathering. Their coloration is protective. They are tall with good eyesight for watchfulness. Giraffes have high blood pressure (240/160) for pumping blood to the brain. Long neck for reaching its food source (leaves)

The Peppered Moth

2 variations of Moths: light and dark Prior to the industrial revolution –

white was favored Post-industrial revolution – black

(peppered) became more common. Why? How do predators and

environments drive evolution?

The Industrial Revolution polluted the environment, raining soot down on the countryside. As a result,

white moths became highly visible on the now blackened tree trunks.

Black moths such as the peppered moth (which

had previously been quite rare), suddenly had a

competitive advantage. They were well

camouflaged on black tree trunks, and their

numbers grew exponentially. By the

early twentieth century, they were the dominant moth form in polluted

areas of the UK.

EVOLUTION BY MEANS OF NATURAL

SELECTION5 Principles

1. Variation All species have variations Variation is the raw material

for natural selection

Ex: Variations in giraffes

2. Struggle for Existence Organisms produce more offspring

than can survive. The environment produces struggles

organisms must surpass to survive

3. Only some survive to reproduce

Some are better able to survive and reproduce (pass on their genes)

4. Natural selection results in genetic change

Each generation contains an increased proportion of individuals with traits that promote survival and reproduction.

What are some alleles that a successful giraffe might have?

Neck length Leg length

5. Species adapt to their environment

Selection makes a population better suited to it’s environment.

The environment determines the direction of genetic change.

What drives the Natural Selection?

*When is a mutation

a ‘good’ mutation

?

Mimicry and

Coloration

Driving Force of Evolution:Competition

Limiting factors – any condition of the environment that limits the size of a population

Carrying capacity – The number of organisms that can be supported by a particular ecosystem

Overpopulation - the condition of having a population so dense as to cause environmental deterioration, an impaired quality of life, or a population crash

RAPID GROWTH “Pyramid”Rapid, Slow or Negative Population Growth?

SLOW GROWTH “Boxy”“Pear Shaped” “Middle Bulge”Rapid, Slow or Negative Population Growth?

Slow vs Fast Which is Fast, which is Slow Growth?

Fast -1930 to Negative 1999Rapid, Slow or Negative Population Growth?

Symbiosis

A close, long-term association between two or more species.

3 types: Mutualism – all participating organisms

benefit Commensalism – one species benefits,

the other is unharmed Parasitism – one species benefits, the

other is harmed (usually not killed – why?)

Factors Affecting Population Changes

Birth Rate Death Rate*usually determine the size of the

base, but also affected by Migration Immigration- movement INTO a

population (migrant workers/child bearing age)

Emigration- movement OUT of a population

Evidence of Evolution

Fossils Bones, casts, footprints, amber, ice

Homologous structures Comparative embryology Vestigial structures Biochemical (DNA and amino acids)

~3.5 Bill yrs Oldest fossils/prok

Cyanobacteria

Endosymbiosis

Land Plants, Animals

200,000- Homo Sapiens (11:59:30)

Primate Evolutionary Tree

Review timelines lab assignment and completed timelines in the classroom NOTE: 1 Meter stick = 1 Billion Years

4.6 Billion (Age of Earth) = ? 10 cm = ?..........1 cm = ?.........1 mm = 1 million

years

Evolutionary Timelines

LAB: Textbook…

Opening of ‘adaptive zones’ – allowed for new species to develop

Mass Extinction

Earth’s Geologic History

Classification of a Leopard

Anthropoids:Monkeys, Apes, Humans~45mya Africa/Asia

Hominoids: Apes, Humans~23-25 mya

Hominids: Humans & ancestors~6-7mya

PROSIMIANS-

“before

primates”

Advanced brain Eyes forward- stereoscopic vision/depth

perception Color vision Acute hearing Dental formula- same #, type,

arrangement of teeth Long slender limbs/rotate freely at

hips/shoulders 5 flexible digits with flattened nails/not

claws Opposable thumbs Complex social behaviors Usually 1 offspring at a time; longer

parental care

Characteristics of Primates

Human Evolution:Australopithecines Homo habilis Homo erectus Homo sapiens

The remains or evidence of any creature or plant that once lived on

the Earth.

Fossils

Fossils are often found in sedimentary rock, which is formed from layers of silt and sand covering dead organisms.

The oldest are found on the lowest layers, youngest in the upper layers

Fossils in Amber(Hardened Tree Sap)

Homologous Structures

Similar structure and anatomical position (but not necessarily the

same function) in different organisms

suggesting a common ancestry

or evolutionary origin

(e.g. wings of bats and arms of humans are homologous).

How Many Neck Vertebrae?

Comparative Embryologythe more closely related any two species are,

the more similar their development

Vestigial Structuresstructures or organs that seem

to serve no useful function

Organisms having vestigial structures probably share a common ancestry with organisms in which the homologous structure is functional

Biochemical/DNA Evidence The closer the DNA sequences of 2

organisms are, the more closely related they are. Ex. Humans and chimps have DNA

that is 99% identical

Dating the Age of Fossils

Carbon-14 dating is a way of determining the age of certain archeological artifacts of a biological origin up to about 60,000 years old. It is used in dating things such as bone, cloth, wood and plant fibers that were created in the relatively recent past by human activities.

This Carbon 14 combines with oxygen to form carbon dioxide,

which plants take in during

photosynthesis

Animals and People eat the plants and take in the C14. We have a set amount of C12 in us, but the amount of C14 changes

while we live.

Once we die, the amount of C14 decreases

(by half in 5,700 years!!)

but the amount of C12 in us

stays constant (It is a STABLE

isotope). So the RATIO C14 to C12 changes

C14 can be used to date

any fossil up to about 60,000

years old…why the limit?

Driving Force of Evolution:Competition

Limiting factors – any condition of the environment that limits the size of a population

Carrying capacity – The number of organisms that can be supported by a particular ecosystem

Overpopulation - the condition of having a population so dense as to cause environmental deterioration, an impaired quality of life, or a population crash

Opening of ‘adaptive zones’ – allowed for new species to develop

3. Mass Extinction

4. Earth’s Geologic History

6th Mass Extinction

Mass Extinction Event – YouTube 9.19

Permian Mass Extinction 5.06

Permian Methane Explosion 5.56