December 8, 2010 Notes - Chapter 15 Evolution Notes - Chapter 15 Evolution HW. – outline Ch. 16 notes HW. – outline Ch. 16 notes Chapter 15 and 16 due

December 8, 2010December 8, 2010•Notes - Chapter 15 EvolutionNotes - Chapter 15 Evolution

•HW. – outline Ch. 16 notesHW. – outline Ch. 16 notes•Chapter 15 and 16 due ThursdayChapter 15 and 16 due Thursday

DefinitionsDefinitions

Evolution = change over timeEvolution = change over time– The process By Which Modern The process By Which Modern

Organisms Have Descended From Organisms Have Descended From Ancient OrganismsAncient Organisms

TheoryTheory– A Well Supported, Testable A Well Supported, Testable

Explanation of Phenomena That Have Explanation of Phenomena That Have Occurred In The Natural WorldOccurred In The Natural World

Voyage of the BeagleVoyage of the Beagle

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

Darwin’s ObservationsDarwin’s Observations

Patterns of Patterns of DiversityDiversity– Unique Unique

AdaptationsAdaptations– Species Not Species Not

Evenly DistributedEvenly Distributed» Australia, Australia,

Kangaroos but No Kangaroos but No RabbitsRabbits

» S. America, LlamasS. America, Llamas

Darwin’s ObservationsDarwin’s Observations

Living Organisms & FossilsLiving Organisms & Fossils– FossilsFossils

» Resembled living organismsResembled living organisms» Where Had These Species Gone?Where Had These Species Gone?» How Were They Related To Living How Were They Related To Living

Species?Species?

The Galapagos IslandsThe Galapagos Islands

Small Group of Islands 1000 km Small Group of Islands 1000 km West of S. AmericaWest of S. America– 3 Very Different Climates3 Very Different Climates– Animals On Islands Unique to the Animals On Islands Unique to the

islandisland» TortoisesTortoises» IguanasIguanas» FinchesFinches

Who else?Who else?

An Ancient, Changing Earth:An Ancient, Changing Earth:

HuttonHutton & & LyellLyell Helped Scientists Helped Scientists Recognize That Recognize That Earth Is Many Millions Earth Is Many Millions of Years Oldof Years Old, And The Processes That , And The Processes That Changed EarthChanged Earth In The Past Are The In The Past Are The Same Processes That Operate In The Same Processes That Operate In The PresentPresent

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

James HuttonJames Hutton– Described The Geological Forces That Described The Geological Forces That

Have Changed The Earth Over Have Changed The Earth Over Millions of YearsMillions of Years» SedimentarySedimentary» VolcanicVolcanic» DisplacementDisplacement» ErosionErosion

Lyell’s Principles of Lyell’s Principles of GeologyGeology

Explained Geological Explained Geological Processes That Processes That Shaped The EarthShaped The Earth– Helped Darwin Helped Darwin

Understand Sea Shells Understand Sea Shells In The Andes In The Andes Mountains At 12,000+ Mountains At 12,000+ FeetFeet

– Expanded Earth’s AgeExpanded Earth’s Age

Lamarck’s Theory of Lamarck’s Theory of EvolutionEvolution

Jean-Baptiste LamarckJean-Baptiste Lamarck– One Of First Scientists One Of First Scientists

To Understand That To Understand That Change Occurs Over Change Occurs Over TimeTime

– Changes Are Changes Are Adaptations To Adaptations To EnvironmentEnvironment

– Almost On The Right Track, Almost On The Right Track, AlmostAlmost


Key ConceptKey Concept– LamarckLamarck Proposed That By Selective Proposed That By Selective

Use Or DisuseUse Or Disuse Of Organs, Organisms Of Organs, Organisms AcquiredAcquired Or Lost Certain Or Lost Certain TraitsTraits During During Their Lifetime. These Traits Could Their Lifetime. These Traits Could Then Be Passed On To Their Then Be Passed On To Their Offspring. Over Time This Led To New Offspring. Over Time This Led To New Species.Species.


Tendency Toward PerfectionTendency Toward Perfection– Organisms Are Continually Changing Organisms Are Continually Changing

and Acquiring Features That Help and Acquiring Features That Help Them Live More Successfully In Their Them Live More Successfully In Their EnvironmentEnvironment» Bird Ancestors Desired To Fly So They Bird Ancestors Desired To Fly So They

Tried Until Wings DevelopedTried Until Wings Developed


Use & DisuseUse & Disuse– Organisms Could Organisms Could

Change The Size Change The Size Or Shape Of Or Shape Of Organs By Using Organs By Using Them Or Not Them Or Not Using ThemUsing Them» Giraffe’s NecksGiraffe’s Necks


Inheritance Of Acquired TraitsInheritance Of Acquired Traits– Traits Acquired During Ones Lifetime Would Be Traits Acquired During Ones Lifetime Would Be

Passed To Offspring (applies to ALL organisms)Passed To Offspring (applies to ALL organisms)– Ex. If you spent much of your life building muscles Ex. If you spent much of your life building muscles

then your offspring would inherit big muscles too!then your offspring would inherit big muscles too!


Lamarck’s ErrorsLamarck’s Errors– Did Not Know About Inheritance of Did Not Know About Inheritance of

TraitsTraits» Genes Are Not Changed By Activities In Genes Are Not Changed By Activities In

LifeLife» Change Through Mutation, Occurs Before Change Through Mutation, Occurs Before

An Organism Is BornAn Organism Is Born

Population GrowthPopulation Growth

Thomas MalthusThomas Malthus– EconomistEconomist– Observed Babies Being Born Faster Observed Babies Being Born Faster

Than People Were DyingThan People Were Dying» Population vs. Food SupplyPopulation vs. Food Supply

Population GrowthPopulation Growth

Key ConceptKey Concept– MalthusMalthus Reasoned Reasoned

That If The Human That If The Human Population Continued Population Continued To Grow Unchecked, To Grow Unchecked, Sooner or Later There Sooner or Later There Would Be Insufficient Would Be Insufficient Living Space & Food Living Space & Food For EveryoneFor Everyone

Population GrowthPopulation Growth Darwin Realized Darwin Realized

Malthus’s Principles Malthus’s Principles Were Visible In Were Visible In Nature. Nature.

Plants & Animals Plants & Animals Produce Far More Produce Far More Offspring Than Can Be Offspring Than Can Be Supported.Supported.– Most DieMost Die– If They Didn’t – Earth If They Didn’t – Earth

Would Be Overrun Would Be Overrun

Population Statistics in the United States From 1900 to 1990

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990

Live births per thousand 32.3 30.1 27.7 21.3 19.4 24.1 23.7 18.4 15.9 15.6

Deaths per thousand 17.1 14.7 13.0 11.3 10.8 9.6 9.5 9.5 8.8 8.7

Number of births over deaths 15.2 15.4 14.7 10.0 8.6 14.5 14.2 8.9 7.1 6.9

Life expectancy at birth (yrs) 47.3 50.0 54.1 59.7 62.9 68.2 69.7 70.8 73.7 74.8

Increase in longevitysince 1900 (yrs)

2.7 6.8 12.4 15.6 20.9 22.4 23.5 26.4 27.5

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

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

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

Why?Why?


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

His Theory Challenged His Theory Challenged Established Religious & Established Religious & Scientific Beliefs, Particularly Scientific Beliefs, Particularly About The Creation Of ManAbout The Creation Of Man


He Refused To Publish He Refused To Publish Until He Received An Until He Received An

Essay From Essay From Alfred Wallace

– Fellow NaturalistFellow Naturalist– Independently Developed Independently Developed

The Same TheoryThe Same Theory

Natural Variation & Artificial Natural Variation & Artificial SelectionSelection

Natural VariationNatural Variation– Differences Among Differences Among

Individuals Of A SpeciesIndividuals Of A Species Artificial SelectionArtificial Selection

– Selective Breeding To Selective Breeding To Enhance Desired Traits Enhance Desired Traits Among Stock or CropsAmong Stock or Crops

Natural Variation & Artificial Natural Variation & Artificial SelectionSelection

In In Artificial Artificial SelectionSelection,, Nature Nature Provided The Provided The Variation Among Variation Among Different Different Organisms, And Organisms, And Humans Selected Humans Selected Those Variations Those Variations That They Found That They Found UsefulUseful

Evolution By Natural SelectionEvolution By Natural Selectionhow does evolution occur?how does evolution occur?

The Struggle for ExistenceThe Struggle for Existence

Survival of the FittestSurvival of the Fittest

Descent with ModificationDescent with Modification

The Struggle for The Struggle for ExistenceExistence

Malthus’ InfluenceMalthus’ Influence– High Birth Rates & Limited High Birth Rates & Limited

Resources Would Force Life & Resources Would Force Life & Death CompetitionDeath Competition

Each Species Struggles For:Each Species Struggles For:– FoodFood– Living SpaceLiving Space– ResourcesResources


FitnessFitness– Ability of an Individual To Ability of an Individual To

Survive &Survive &

ReproduceReproduce AdaptationAdaptation

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


AdaptationsAdaptations Can Be: Can Be:– PhysicalPhysical

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

– BehavioralBehavioral»Solitary, Herds, Packs, Solitary, Herds, Packs, Activity, etc.Activity, etc.


FitnessFitness Is Core To The Process Is Core To The Process Of EvolutionOf Evolution

Individuals With Low FitnessIndividuals With Low Fitness– DieDie– Produce Few OffspringProduce Few Offspring

Survival of the Fittest Survival of the Fittest AKA AKA Natural Natural SelectionSelection


Over Time, Natural Selection Over Time, Natural Selection Results In Results In ChangesChanges In The In The Inherited Inherited CharacteristicsCharacteristics Of Of A Population. These Changes A Population. These Changes IncreaseIncrease A Species A Species FitnessFitness In In Its EnvironmentIts Environment

Descent With ModificationDescent With Modification

Over Long PeriodsOver Long Periods Natural Selection Can Be Natural Selection Can Be

Observed As Changes InObserved As Changes In– Body StructuresBody Structures– Ecological NichesEcological Niches– HabitatsHabitats


Species Today Look Different Species Today Look Different From Their AncestorsFrom Their Ancestors

Each Living Species HasEach Living Species Has– DescendedDescended– With ChangesWith Changes– From Other SpeciesFrom Other Species– Over TimeOver Time


ImpliesImplies– All Living Organisms Are RelatedAll Living Organisms Are Related– Single Tree of LifeSingle Tree of Life

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

Common DescentCommon Descent– All Species, Living & Extinct, All Species, Living & Extinct,

Were Derived From Common Were Derived From Common AncestorsAncestors

Evidence of EvolutionEvidence of EvolutionDarwin Argued That Living Things Darwin Argued That Living Things

Have Been Evolving On Earth For Have Been Evolving On Earth For Millions of Years. Evidence For Millions of Years. Evidence For This Process Could Be Found In:This Process Could Be Found In:– The Fossil RecordThe Fossil Record– The Geographical Distribution of The Geographical Distribution of

Living SpeciesLiving Species– Homologous Structures of Living Homologous Structures of Living

OrganismsOrganisms– Similarities In Early DevelopmentSimilarities In Early Development

Fossil RecordFossil Record

Earth is Billions of Years OldEarth is Billions of Years Old FossilsFossils In Different Layers of In Different Layers of

Rock Rock ShowedShowed Evidence Of Evidence Of Gradual Gradual ChangeChange Over Time Over Time

Geographic Distribution of Living Geographic Distribution of Living SpeciesSpecies

DifferentDifferent Animals On Animals On DifferentDifferent Continents But Continents But SimilarSimilar AdaptationsAdaptations To Shared To Shared EnvironmentsEnvironments

Homologous Body StructuresHomologous Body Structures

Scientists Noticed Animals Scientists Noticed Animals With Backbones Had Similar With Backbones Had Similar Bone StructureBone Structure– May May DifferDiffer In Form or Function In Form or Function

» Arms, Wings, Legs, FlippersArms, Wings, Legs, Flippers

– Limb Bones Develop In Limb Bones Develop In SimilarSimilar PatternsPatterns


Homologous StructuresHomologous Structures

– Structures That Have Different Structures That Have Different Mature Forms But Develop From Mature Forms But Develop From The Same Embryonic TissuesThe Same Embryonic Tissues

– Shows Strong Evidence of A Shows Strong Evidence of A Common AncestorCommon Ancestor



Not All homologous structures Not All homologous structures Serve Important FunctionsServe Important Functions– Vestigial OrgansVestigial Organs

» Appendix In ManAppendix In Man» Legs On Skinks (type of lizard)Legs On Skinks (type of lizard)

Similarities In Early Similarities In Early DevelopmentDevelopment

Embryonic Embryonic Structures Of Structures Of Different Different Species Show Species Show Significant Significant SimilaritiesSimilarities

Chicken Turtle

RatHuman

REVIEW: Darwin's TheoryREVIEW: Darwin's Theory

1.1. Individual Organisms In Nature Individual Organisms In Nature Differ From One Another. Differ From One Another. Some Of This Variation Is Some Of This Variation Is InheritedInherited

2.2. Organisms In Nature Produce Organisms In Nature Produce More Offspring Than Can More Offspring Than Can Survive, And Many Of These Survive, And Many Of These Offspring Do No ReproduceOffspring Do No Reproduce

Darwin's TheoryDarwin's Theory

3.3. Because More Organisms Are Because More Organisms Are Produced Than Can Survive, Produced Than Can Survive, Members Of Each Species Must Members Of Each Species Must Compete For Limited ResourcesCompete For Limited Resources

4.4. Because Each Organism Is Unique, Because Each Organism Is Unique, Each Has Different Advantages & Each Has Different Advantages & Disadvantages In The Struggle For Disadvantages In The Struggle For ExistenceExistence


5.5. Individuals Best Suited To Their Individuals Best Suited To Their Environment Survive & Reproduce Environment Survive & Reproduce Successfully – Passing Their Traits Successfully – Passing Their Traits To Their Offspring.To Their Offspring.

6.6. Species Change Over Time. Over Species Change Over Time. Over Long Periods, Natural Selection Long Periods, Natural Selection Causes Changes That May Causes Changes That May Eventually Lead To New SpeciesEventually Lead To New Species


7.7. Species Alive Today Have Species Alive Today Have Descended With Modifications Descended With Modifications From Species That Lived In From Species That Lived In The PastThe Past

8.8. All Organisms On Earth Are All Organisms On Earth Are United Into A Single Tree Of United Into A Single Tree Of Life By Common DescentLife By Common Descent

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December 8, 2010 Notes - Chapter 15 Evolution Notes - Chapter 15 Evolution HW. – outline Ch. 16 notes HW. – outline Ch. 16 notes Chapter 15 and 16 due