Chapter 15Chapter 15Section 1: Theories of Section 1: Theories of

EvolutionEvolution

Lamarck’ Theory of Lamarck’ Theory of EvolutionEvolution• Organisms had need/desire to Organisms had need/desire to

improveimprove• Use and disuseUse and disuse• Inheritance of acquired Inheritance of acquired

characteristicscharacteristics

Charles Darwin – The TripCharles Darwin – The Trip• Charles Darwin: The naturalistCharles Darwin: The naturalist• Traveled on Traveled on H.M.S. BeagleH.M.S. Beagle in 1831 to in 1831 to

the Galapagos Islandsthe Galapagos Islands– ClimatesClimates– FinchesFinches– TortoisesTortoises

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Hawaiian Honeycreeper

Darwin and Modern Darwin and Modern EvolutionEvolution• Darwin: A brief historyDarwin: A brief history• Influences on Darwin:Influences on Darwin:

– Trip to the Galapagos IslandsTrip to the Galapagos Islands– Hutton and Lyell (Unifromitarianism)Hutton and Lyell (Unifromitarianism)– Thomas MalthusThomas Malthus– Alfred WallaceAlfred Wallace

• Publication of Publication of The Origin of SpeciesThe Origin of Species - - 18591859

Darwin’s Application of Darwin’s Application of MalthusMalthus

– Organisms produce more offspring Organisms produce more offspring than can survivethan can survive

– This produces a struggle for existenceThis produces a struggle for existence– Each member has variationsEach member has variations– Those with variations that give the Those with variations that give the

organism an advantage will have the organism an advantage will have the best chance for survival = “survival of best chance for survival = “survival of the fittestthe fittest””

Darwin’s TheoriesDarwin’s Theories• Descent with ModificationDescent with Modification

– Common ancestryCommon ancestry• Modification by Natural SelectionModification by Natural Selection

– FitnessFitness– Adaptive advantageAdaptive advantage– Source of adaptation?Source of adaptation?– Definition of successDefinition of success

Explaining Natural SelectionExplaining Natural Selection• Occurs when organisms with Occurs when organisms with higher higher

fitnessfitness survive, reproduce and survive, reproduce and successfully pass on their traitssuccessfully pass on their traits

• Organisms with lower fitness are less Organisms with lower fitness are less likely to survive likely to survive

• Eventually, population is made up of Eventually, population is made up of only those with higher fitnessonly those with higher fitness

QODQODWhat evidence do we have to What evidence do we have to support evolution by natural support evolution by natural

selection?selection?

FossilsFossils• Definition:Definition:• Types:Types:

– MoldMold– CastCast– AmberAmber– FrozenFrozen– ImprintImprint– TraceTrace– MineralizedMineralized

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How Fossils Form

Distribution of FossilsDistribution of Fossils• LocationLocation

– Type of rockType of rock– Law of superpositionLaw of superposition– Stratum/StrataStratum/Strata

• AgeAge– Relative ageRelative age– Absolute ageAbsolute age

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Fossils in Rock Layers

Succession and Succession and BiogeographyBiogeography• Succession of FormsSuccession of Forms

– ExtinctionExtinction– Mass extinctionMass extinction

• BiogeographyBiogeography

Evidence for EvolutionEvidence for Evolution• FossilsFossils• Homologous StructuresHomologous Structures• Analogous StructuresAnalogous Structures• Vestigial StructuresVestigial Structures• EmbryologyEmbryology• MacromoleculesMacromolecules

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Homologous Structures

Analogous structuresAnalogous structures

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Vestigial Structures

Other Forms of EvidenceOther Forms of Evidence

Patterns of EvolutionPatterns of Evolution• CoevolutionCoevolution• Convergent evolutionConvergent evolution• Divergent evolutionDivergent evolution

– Adaptive radiationAdaptive radiation– Artificial selectionArtificial selection

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Hawaiian Honeycreeper

QODQODWhere do we see natural Where do we see natural selection in action today?selection in action today?

Kettlewell and the peppered Kettlewell and the peppered mothmoth

Antibiotic resistanceAntibiotic resistance