ch. 15 the theory of evolution unit 4 :. evolution chapter 15 diversity of life

Ch. 15 The Theory of Ch. 15 The Theory of EvolutionEvolution

Unit 4Unit 4::

EvolutionChapter 15

Diversity of Life

““Nothing in Nothing in biology makes biology makes

sense EXCEPT in sense EXCEPT in the light of the light of evolution.” evolution.” Theodosius Theodosius DobzhanskyDobzhansky

Charles Darwin in later Charles Darwin in later yearsyears

History of History of

Evolutionary Evolutionary

ThoughtThought

Early Ideas On Earth’s Early Ideas On Earth’s OrganismsOrganisms

AristotleAristotle believed believed species were species were fixed creationsfixed creations arranged by arranged by their their complexity.complexity.

Idea Idea lasted lasted 20002000 years. years.

Early Ideas On Earth’s Early Ideas On Earth’s OrganismsOrganisms

LinnaeusLinnaeus – 1 – 1stst to to group similar group similar organisms and organisms and assign them assign them LatinLatin names.names.

Two word name Two word name (Genus species)(Genus species)

Known as Known as Binomial Binomial nomenclaturenomenclature . .

Contributor’s to Darwin’s Contributor’s to Darwin’s thinking included:thinking included:

• Charles Lyell –Charles Lyell –uniformintarianism uniformintarianism (geologic processes still (geologic processes still changing Earth).changing Earth).

• Georges Cuvier – Georges Cuvier – species species extinction (Catastrophism).extinction (Catastrophism).

• Thomas Malthus – Thomas Malthus – struggle for struggle for existence (resources).existence (resources).

Contributor’s to Darwin’s Contributor’s to Darwin’s thinking included:thinking included:

• James Hutton - James Hutton - GradualismGradualism• John Baptiste Lamarck – John Baptiste Lamarck –

Inheritance of acquired Inheritance of acquired CharacteristicsCharacteristics andand Law of Use Law of Use and Disuse.and Disuse.

• Alfred Russel Wallace – Alfred Russel Wallace – organisms evolved from common organisms evolved from common ancestors.ancestors.

CatastrophismCatastrophism

Idea proposed by Idea proposed by George CuvierGeorge CuvierStudied fossil in Studied fossil in sedimentary sedimentary

rock stratarock strata of Paris of ParisFound Found some species completely some species completely

disappeareddisappeared in more recent in more recent layerslayers

CatastrophismCatastrophism

Stated that Stated that species species disappear due disappear due to a to a catastrophic catastrophic event of the event of the earth’s crustearth’s crust (volcano, (volcano, earthquake…)earthquake…)

Hutton’s Theory of Hutton’s Theory of Geological ChangeGeological Change

James HuttonJames Hutton, 1795, Scottish , 1795, Scottish geologistgeologistStudied Studied invertebrate fossils in invertebrate fossils in Paris MuseumParis MuseumDescribed The Described The Geological ForcesGeological Forces That Have Changed That Have Changed LifeLife on Earthon Earth Over Millions of Years (erosion, Over Millions of Years (erosion, earthquakes, volcanoes…)earthquakes, volcanoes…)

Hutton’s Theory of Hutton’s Theory of Geological ChangeGeological Change

Changes in Changes in Earth’s crust Earth’s crust due to due to slow slow continuous continuous processesprocesses

Idea Known as Idea Known as GradualismGradualism

Charles LyellCharles Lyell

Proposed theory of Proposed theory of UniformintarianismUniformintarianism

Geological processes Geological processes at at uniform ratesuniform rates building & wearing building & wearing down Earth’s crustdown Earth’s crust

Proposed that the Proposed that the Earth was millions of Earth was millions of yearsyears instead of a instead of a few thousand years few thousand years oldold

Principles of GeologyPrinciples of Geology

Published by Published by LyellLyell Just Before The Just Before The BeagleBeagle Set Sail & read by Darwin Set Sail & read by Darwin

Explained Explained Geological Processes Geological Processes That Shaped The EarthThat Shaped The Earth

Helped Darwin Understand Helped Darwin Understand Sea Sea Shells In The Andes Mountains At Shells In The Andes Mountains At 12,000+ Feet12,000+ Feet

Expanded Earth’s AgeExpanded Earth’s Age

Lamarck’s Theory of Lamarck’s Theory of EvolutionEvolution

Jean-Baptiste LamarckJean-Baptiste Lamarck, , 18091809

One Of First Scientists One Of First Scientists To Understand That To Understand That Change Occurs Over Change Occurs Over TimeTime

Stated that Changes Stated that Changes Are Adaptations To Are Adaptations To Environment Environment acquired acquired in an organism’s in an organism’s lifetimelifetime

Said acquired changes Said acquired changes were passed to were passed to offspringoffspring


Idea called Idea called Law Law of Use and of Use and DisuseDisuse

If a body part If a body part were used, it were used, it got strongergot stronger

If body part If body part NOT used, it NOT used, it deteriorateddeteriorated


Inheritance of Acquired Inheritance of Acquired CharacteristicsCharacteristics

Proposed That By Selective Use Or Proposed That By Selective Use Or Disuse Of Organs, Organisms Disuse Of Organs, Organisms Acquired Or Lost Certain Traits Acquired Or Lost Certain Traits During Their LifetimeDuring Their Lifetime

These These Traits Could Then Be Traits Could Then Be Passed On To Their OffspringPassed On To Their Offspring

Over Time This Led To Over Time This Led To New New SpeciesSpecies


Use & Disuse - Use & Disuse - Organisms Could Organisms Could Change The Size Or Change The Size Or Shape Of Organs Shape Of Organs By Using Them Or By Using Them Or Not Using ThemNot Using Them

Blacksmiths & Blacksmiths & Their SonsTheir Sons (muscular arms)(muscular arms)

Giraffe’s Necks Giraffe’s Necks LongerLonger from from stretching)stretching)


Inheritance Of Acquired TraitsInheritance Of Acquired TraitsTraits Acquired During Ones Lifetime Traits Acquired During Ones Lifetime

Would Be Passed To OffspringWould Be Passed To Offspring

Clipped ears of dogs could be passed to Clipped ears of dogs could be passed to offspring.offspring.


Tendency Toward PerfectionTendency Toward PerfectionOrganisms Are Continually Organisms Are Continually

Changing and Acquiring Features Changing and Acquiring Features That Help Them Live More That Help Them Live More Successfully In Their Successfully In Their EnvironmentEnvironment

Example:Example: Bird Ancestors Desired Bird Ancestors Desired To Fly So They Tried Until Wings To Fly So They Tried Until Wings DevelopedDeveloped

Lamarck’s MistakesLamarck’s Mistakes

Lamarck Did NOT Know how Lamarck Did NOT Know how traits were traits were inherited (Traits are inherited (Traits are passed through genes)passed through genes)

Genes Are NOT Changed By Genes Are NOT Changed By Activities In LifeActivities In Life

Change Through Change Through Mutation Occurs Mutation Occurs Before An Organism Is BornBefore An Organism Is Born

Charles Darwin the Charles Darwin the NaturalistNaturalist

Voyage of the BeagleVoyage of the Beagle

Charles DarwinCharles Darwin Born Feb. 12, 1809.Born Feb. 12, 1809. Joined Crew of HMS Joined Crew of HMS

Beagle, 1831.Beagle, 1831. NaturalistNaturalist 5 Year Voyage around 5 Year Voyage around

world.world. Avid Collector of Flora Avid Collector of Flora

& Fauna.& Fauna. Astounded By Variety Astounded By Variety

of Life.of Life.

Darwin’s Voyage of Darwin’s Voyage of DiscoveryDiscovery

A reconstruction of the HMS Beagle A reconstruction of the HMS Beagle sailing off Patagonia.sailing off Patagonia.

Darwin Left England in Darwin Left England in 18311831

Darwin returned 5 years later in Darwin returned 5 years later in 18361836

HMS Beagle’s VoyageHMS Beagle’s Voyage

The Galapagos IslandsThe Galapagos Islands

Small Group of Islands Small Group of Islands 1000 km West of South 1000 km West of South AmericaAmerica

Very Different ClimatesVery Different ClimatesAnimals On Islands Animals On Islands

UniqueUniqueTortoisesTortoisesIguanasIguanasFinchesFinches


Volcanic islandsVolcanic islands off off the coast of South the coast of South AmericaAmerica

Island species varied Island species varied from mainland from mainland species & from species & from island-to-island island-to-island speciesspecies

Each island had long Each island had long or short neck or short neck tortoisestortoises


Finches on the islands Finches on the islands resembled a resembled a mainland finchmainland finch

More types of finches appeared on More types of finches appeared on the islandsthe islands where the available food where the available food was different (seeds, nuts, berries, was different (seeds, nuts, berries, insects…)insects…)

Finches had Finches had different types of beaksdifferent types of beaks adapted to their adapted to their type of food type of food gatheringgathering

Darwin’s Observations & Darwin’s Observations & ConclusionsConclusions

The Struggle for The Struggle for ExistenceExistence

Voyage of the BeagleVoyage of the Beagle

During His Travels, Darwin Made During His Travels, Darwin Made Numerous Observations And Numerous Observations And Collected Evidence That Led Him Collected Evidence That Led Him To Propose A To Propose A Revolutionary Revolutionary HypothesisHypothesis About The Way Life About The Way Life Changes Over TimeChanges Over Time

Darwin’s ObservationsDarwin’s Observations

Patterns of Patterns of Diversity were Diversity were shownshown

Unique Adaptations Unique Adaptations in organismsin organisms

Species Not Evenly Species Not Evenly DistributedDistributed

Australia, Australia, Kangaroos, but No Kangaroos, but No RabbitsRabbits

S. America, S. America, LlamasLlamas


Both Living Organisms & Both Living Organisms & Fossils collectedFossils collected

Fossils included:Fossils included:TrilobitesTrilobitesGiant Ground Sloth of Giant Ground Sloth of South AmericaSouth America

This species NO longer existed.This species NO longer existed. What had happened to them?What had happened to them?

Evidence for Evolution – Evidence for Evolution – The Fossil RecordThe Fossil Record

DefinitionDefinition

Evolution is the slow , gradual change in a population of organisms over time


Left unchecked, the number of organisms of each species will increase exponentially, generation to generation.

In nature, populations tend to remain stable in size.

Environmental resources are limited.

Darwin’s ConclusionDarwin’s Conclusion

• Production of more individuals than can be supported by the environment leads to a struggle for existence among individuals.

• Only a fraction of offspring survive each generation.

• Survival of the Fittest.


• Individuals of a population vary extensively in their characteristics with no two individuals being exactly alike.

• Much of this variation between individuals is inheritable.

Darwin’s ConclusionDarwin’s Conclusion

• Individuals who inherit characteristics most fit for their environment are likely to leave more offspring than less fit individuals.

• Called Natural Selection.

Darwin’s Darwin’s Theory of Theory of EvolutionEvolution

• The The unequal ability of individuals to unequal ability of individuals to survive and reproducesurvive and reproduce leads to a gradual leads to a gradual change in a population, with favorable change in a population, with favorable characteristics accumulating over characteristics accumulating over generations generations (natural selection)(natural selection)

• New species evolveNew species evolve

Darwin’s Theory of Darwin’s Theory of EvolutionEvolution

Organisms Organisms Change Over Change Over

TimeTime

Common Descent with Common Descent with ModificationModification

Darwin proposed Darwin proposed that organisms that organisms descended from descended from common ancestors.common ancestors.

Idea that organisms Idea that organisms change with timechange with time, , diverging from a diverging from a common form.common form.

Caused Caused evolution of evolution of new speciesnew species . .

Natural Selection

Driving forceDriving force for for evolutionevolution

During the struggle for During the struggle for resources, resources, strongest strongest survive & reproducesurvive & reproduce

Idea that at least Idea that at least some some of the differencesof the differences between individuals, between individuals, which impact their which impact their survival and fertility, survival and fertility, are are inheritableinheritable

Origin of SpeciesOrigin of Species

Darwin Presents His CaseDarwin Presents His Case

Publication of “On The Publication of “On The Origin of Species”Origin of Species”

Upon His Return To England, Upon His Return To England, Darwin Developed His Observations Darwin Developed His Observations Into The Theory of EvolutionInto The Theory of Evolution

But He But He Did Not Publish For 25 Did Not Publish For 25 YearsYears – –

Why?Why?


Darwin Knew That His Theory Darwin Knew That His Theory Would Be Would Be Extremely Extremely ControversialControversial And Would Be And Would Be AttackedAttacked

His Theory His Theory Challenged Challenged Established Religious & Scientific Established Religious & Scientific BeliefsBeliefs, Particularly About The , Particularly About The Creation Of ManCreation Of Man


He Refused To Publish He Refused To Publish Until He Received An Until He Received An Essay From Essay From Alfred WallaceAlfred WallaceFellow NaturalistFellow NaturalistIndependently Independently

Developed The Same Developed The Same TheoryTheory

After 25 Years, Someone After 25 Years, Someone Else Had Come To The Else Had Come To The Same Conclusions From Same Conclusions From Their Observations Of Their Observations Of NatureNature

Wallace’s ContributionWallace’s Contribution

• Alfred Russel WallaceAlfred Russel Wallace Independently came Independently came to same Conclusion to same Conclusion as Darwin that as Darwin that species changed over species changed over time because of their time because of their struggle for struggle for existenceexistence

• When Darwin read When Darwin read Wallace’s essay, Wallace’s essay, he he knew he had to knew he had to publish his findingspublish his findings


Darwin Presented Wallace’s Darwin Presented Wallace’s Essay & Some Of His Work At A Essay & Some Of His Work At A Scientific Conference of the Scientific Conference of the Linnaean SocietyLinnaean Society in July of in July of 18581858

Then He Started On his book Then He Started On his book “Origin of Species”“Origin of Species”

It Took Darwin 18 Months To It Took Darwin 18 Months To Complete The BookComplete The Book

Natural Variation and Natural Variation and Artificial SelectionArtificial Selection

Abandoned The IdeaAbandoned The Idea That Species That Species Were Perfect & UnchangingWere Perfect & Unchanging

Observed Observed Significant Variation in Significant Variation in All SpeciesAll Species Observed Observed

Observed Observed Farmers Use VariationFarmers Use Variation To Improve Crops & Livestock To Improve Crops & Livestock

Called Called Selective BreedingSelective Breeding


Natural VariationNatural VariationDifferences Among Individuals Differences Among Individuals

Of A SpeciesOf A SpeciesArtificial SelectionArtificial Selection

Selective Breeding To Enhance Selective Breeding To Enhance Desired Traits Among Stock or Desired Traits Among Stock or CropsCrops


Key Concept:Key Concept:

In In Artificial SelectionArtificial Selection,, Nature Nature Provided The Variation Provided The Variation Among Different Among Different Organisms, And Humans Organisms, And Humans Selected Those Variations Selected Those Variations That They Found UsefulThat They Found Useful

Origin of SpeciesOrigin of Species

Concepts and Concepts and ControversyControversy

Evolution By Natural Evolution By Natural Selection ConceptsSelection Concepts

The Struggle for ExistenceThe Struggle for Existence (compete for food, mates, space, (compete for food, mates, space, water, etc.)water, etc.)

Survival of the FittestSurvival of the Fittest (strongest (strongest able to survive and reproduce)able to survive and reproduce)

Descent with Modification Descent with Modification (new (new species arise from common species arise from common ancestor replacing less fit ancestor replacing less fit species)species)

Survival of the FittestSurvival of the Fittest

Fitness Ability of an Individual To Ability of an Individual To

Survive & ReproduceSurvive & Reproduce Adaptation

Inherited Characteristic That Inherited Characteristic That Increases an Organisms Increases an Organisms Chance for SurvivalChance for Survival


Adaptations Can Be:Physical

Speed, Camouflage, Claws, Speed, Camouflage, Claws, Quills, etc.Quills, etc.

BehavioralBehavioralSolitary, Herds, Packs, Solitary, Herds, Packs, Activity, etc.Activity, etc.


Fitness Is Central To The Is Central To The Process Of EvolutionProcess Of Evolution

Individuals With Low FitnessIndividuals With Low FitnessDieDieProduce Few OffspringProduce Few Offspring

Survival of the Fittest

AKA AKA Natural Selection


Key ConceptOver Time, Natural Selection Over Time, Natural Selection Results In Changes In The Results In Changes In The Inherited Characteristics Of Inherited Characteristics Of A Population. These A Population. These Changes Increase A Species Changes Increase A Species Fitness In Its EnvironmentFitness In Its Environment

Natural SelectionNatural Selection

Descent With ModificationDescent With Modification

Takes Place Over Takes Place Over Long Periods of Time of Time

Natural Selection Can Be Natural Selection Can Be Observed As Changes In As Changes InBody StructuresBody StructuresEcological NichesEcological NichesHabitatsHabitats


ImpliesImpliesAll Living Organisms Are RelatedAll Living Organisms Are RelatedSingle Tree of LifeSingle Tree of Life

DNA, Body Structures, Energy DNA, Body Structures, Energy SourcesSources

Common DescentAll Species, Living & Extinct, All Species, Living & Extinct,

Were Derived From Common Were Derived From Common AncestorsAncestors

Major Problem in Darwin’s Theory

• No mechanism to explain natural selection

• How could favorable variations be transmitted to later generations?

• With the rediscovery of Mendel’s work in the first half of the 20th century, the missing link in evolutionary theory was found

Opposition to EvolutionOpposition to Evolution

• The upheaval surrounding evolution began with Darwin’s publication of On the Origin of Species By Means of Natural Selection

• The debate continues nearly 150 years later

I. Work of Charles DarwinI. Work of Charles DarwinA. A. Charles DarwinCharles Darwin gave us the gave us the

Theory of Evolution.Theory of Evolution.B. Theory of Evolution from study on B. Theory of Evolution from study on

Galapagos IslandsGalapagos Islands1. Nature uses 1. Nature uses natural selectionnatural selection = only = only

the strong survive.the strong survive.2. The 2. The allelesalleles that increase survival rate that increase survival rate

become become dominant.dominant.3. 3. Artificial SelectionArtificial Selection = nature allows for = nature allows for

the weak to die before breeding, leading the weak to die before breeding, leading to the stronger mating cause specific to the stronger mating cause specific traits to show.traits to show.

II. Evidence Darwin says Proves II. Evidence Darwin says Proves EvolutionEvolution

A. Camouflage = insects that blend A. Camouflage = insects that blend in with environment escape in with environment escape predators; increase survival.predators; increase survival.

B. Mimicry = insects that look similar B. Mimicry = insects that look similar to other insects that birds will not to other insects that birds will not eat; these genes increase survival eat; these genes increase survival rate rate Ex: viceroy butterfly and Monarch Ex: viceroy butterfly and Monarch

butterfly. Monarch favorite food of birdsbutterfly. Monarch favorite food of birds

C. Embryo of fish, reptile, bird, C. Embryo of fish, reptile, bird, mammal look very much alike in mammal look very much alike in beginning all have gill slits and tailsbeginning all have gill slits and tails

D. Vestigial Structure = have an D. Vestigial Structure = have an organ but has no function for organ but has no function for organism.organism.Ex: appendix of manEx: appendix of man

E. Biochemistry = DNA of different E. Biochemistry = DNA of different species is very similar.species is very similar.

F. Homologous structures = bones of F. Homologous structures = bones of various animals have the same various animals have the same pattern and similar functions (see pg. pattern and similar functions (see pg. _____)_____)

(Homologous Structures)(Homologous Structures)

G. Analogous structures = structures G. Analogous structures = structures are similar in function but the are similar in function but the materials of the structures are materials of the structures are differentdifferentEx: bird’s wing to butterfly wingEx: bird’s wing to butterfly wing

H. Fossils show a change in a specific H. Fossils show a change in a specific animal’s structureanimal’s structure

I. Today we see evolution in bacteria I. Today we see evolution in bacteria – penicillin is not effective on new – penicillin is not effective on new strands of bacteria (evolution strands of bacteria (evolution happened)happened)

(Analogous Structures)(Analogous Structures)

Homologous vs AnalogousHomologous vs Analogous

II.II. Evidence of Evolution.Evidence of Evolution.(Biochemical)(Biochemical)

Comparing genetic informationComparing genetic information (the sequence of amino acids)(the sequence of amino acids)DNA Fingerprinting (gel DNA Fingerprinting (gel

electrophoresis)electrophoresis)

Ex. Ex. Hemoglobin Hemoglobin (red blood cell (red blood cell protein)protein)The amino acid sequence for this The amino acid sequence for this protein in humans is almost identical protein in humans is almost identical to the sequence in gorillas. Differ by to the sequence in gorillas. Differ by one amino acid. In frogs, it differs by one amino acid. In frogs, it differs by 67 amino acids. So, humans and 67 amino acids. So, humans and gorillas shared a common ancestor gorillas shared a common ancestor more recently than humans and more recently than humans and frogs.frogs.

ch. 15 the theory of evolution unit 4 :. evolution chapter 15 diversity of life

Documents

theory of evolutionunit

earths organismsaristotle

earths organismslinnaeus

earths crustproposed

earths crust volcano

similar organisms

organisms lifetimesaid

geological forces