evolution evolution chapter 16.1, 16.2, and 16.3 1

EvolutionEvolution

Chapter 16.1, 16.2, and 16.3Chapter 16.1, 16.2, and 16.311

Overall Theme of Overall Theme of

EvolutionEvolution

Evolution Requires 3 elements:Evolution Requires 3 elements: 1. Variety1. Variety 2. Selection2. Selection 3. Time3. Time

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VarietyVariety

For evolution to occur, there must be For evolution to occur, there must be ways for organisms within a species to ways for organisms within a species to be different from each otherbe different from each other

Variety is generated through Variety is generated through mutationsmutations and and sexual reproduction sexual reproduction

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Evolution is now Evolution is now considered a Theory considered a Theory

What is the difference between a Theory What is the difference between a Theory and a Hypothesis?and a Hypothesis?

Theory- a hypothesis that has been confirmed Theory- a hypothesis that has been confirmed by testing and has much evidence backing it by testing and has much evidence backing it upup

Hypothesis- an educated guess that can be Hypothesis- an educated guess that can be testedtested

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Charles DarwinCharles Darwin

Charles Darwin took many Charles Darwin took many years to publish his theory of years to publish his theory of evolution by natural evolution by natural selection. selection.

Many of his ideas were first Many of his ideas were first inspired by his 1831 global inspired by his 1831 global voyage on the ship called voyage on the ship called the the Beagle.Beagle.

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Charles Darwin Charles Darwin (1809 – 1882)(1809 – 1882)

In l831, when Darwin was only 22 he In l831, when Darwin was only 22 he signed on as the ship’s naturalist aboard signed on as the ship’s naturalist aboard the the BeagleBeagle on a 5-year expedition around on a 5-year expedition around the world.the world.

Darwin studied and collected many Darwin studied and collected many different and unusual specimens which different and unusual specimens which contributed to his theory.contributed to his theory.

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Darwin’s Voyage to the Darwin’s Voyage to the Galapagos IslandsGalapagos Islands

Some of Darwin’s most important Some of Darwin’s most important observations were made on the observations were made on the Galapagos Islands.Galapagos Islands.

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Animals of the Animals of the Galapagos IslandsGalapagos Islands

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Blue Footed Boobies in the Galapagos

Galapagos Islands: Galapagos Islands: FinchesFinches

Darwin observed Darwin observed organisms with organisms with slight differences. slight differences.

Example: GalápagosExample: Galápagosfinches withfinches withdifferent beaksdifferent beaks

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Assumptions At That Assumptions At That TimeTime

Species were fixed creations that Species were fixed creations that never changed and they were never changed and they were arranged from least complex to most arranged from least complex to most complex.complex.

Earth is only a few thousand years Earth is only a few thousand years old.old.

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Darwin’s Book: Darwin’s Book: On the Origin of SpeciesOn the Origin of Species

Darwin’s book stated:Darwin’s book stated:1)1) Species change Species change

2)2) Species evolved from a common Species evolved from a common ancestor over time (implying a much ancestor over time (implying a much older Earth)older Earth)

3)3) Natural SelectionNatural Selection is the mechanism for is the mechanism for changechange

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The only picture in The only picture in Darwin’s book shows Darwin’s book shows

Common Ancestry Common Ancestry

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Who influenced Who influenced Darwin’s Ideas?Darwin’s Ideas?

1.1. Jean Baptiste Lamarck (Biology) Jean Baptiste Lamarck (Biology)

2.2. Thomas Malthus (Economics)Thomas Malthus (Economics)

3.3. Charles Lyell (Geology)Charles Lyell (Geology)

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Jean Baptiste LamarckJean Baptiste Lamarck

Lamarck proposed that organisms Lamarck proposed that organisms change over time as they adapt to change over time as they adapt to changing environmentschanging environments..

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Jean Baptiste LamarckJean Baptiste Lamarck

He also He also incorrectlyincorrectly proposed that proposed that changes due to use and disuse of a changes due to use and disuse of a characteristic would be passed on to characteristic would be passed on to offspring. offspring.

Example: A baseball player’s children would Example: A baseball player’s children would inherit strong arm muscles inherit strong arm muscles

Giraffe’s neck stretches Giraffe’s neck stretches

to reach foodto reach food

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Charles LyellCharles Lyell

Lyell studied fossils and rock layers Lyell studied fossils and rock layers

His work showed that Earth’s history His work showed that Earth’s history was long enough for species to have was long enough for species to have evolved graduallyevolved gradually..

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Charles LyellCharles Lyell

Lyell found evidence of long extinct Lyell found evidence of long extinct habitats habitats

Example: Fossil sea shells in the Andes Example: Fossil sea shells in the Andes MountainsMountains

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Thomas MalthusThomas Malthus

Malthus observed that human Malthus observed that human populations were increasing faster than populations were increasing faster than the food supply.the food supply.

Darwin saw that all kinds of organisms Darwin saw that all kinds of organisms tend to produce more offspring than can tend to produce more offspring than can survive. survive.

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Darwin’s Theory of Darwin’s Theory of Natural SelectionNatural Selection

1)1) OverproductionOverproduction- Organisms produce more - Organisms produce more offspring than can survive. Leads to competition for offspring than can survive. Leads to competition for resources.resources.

2)2) VarietyVariety- Variation exists within every population. - Variation exists within every population.

3)3) SelectionSelection- Having a particular trait can make - Having a particular trait can make individuals more or less likely to survive and individuals more or less likely to survive and reproduce offspringreproduce offspring

4) 4) AdaptationAdaptation– Over time, the traits that improve – Over time, the traits that improve survival and reproduction become more common.survival and reproduction become more common.

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Artificial SelectionArtificial Selection

A human practice of breeding A human practice of breeding animals or plants that have animals or plants that have desired traitsdesired traits

Example: Pigeon and Dog Example: Pigeon and Dog breedersbreeders

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Artificial SelectionArtificial Selection

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Evidence for Evidence for Evolutionary TheoryEvolutionary Theory

1.1. Galapagos FinchesGalapagos Finches

2.2. Transitional FossilsTransitional Fossils

3.3. BiogeographyBiogeography

4.4. EmbryologyEmbryology

5.5. Homologous StructuresHomologous Structures

6.6. BiochemistryBiochemistry

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Galapagos Finches Galapagos Finches

All Galapagos finch species are similar to All Galapagos finch species are similar to each other. each other.

Beak size and shape are different due to Beak size and shape are different due to different types of food.different types of food.

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Transitional FossilsTransitional Fossils

Traces of organisms that lived in the Traces of organisms that lived in the past. past.

Some fossils show a pattern of gradual Some fossils show a pattern of gradual change from the past to the presentchange from the past to the present

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Transitional FossilsTransitional Fossils

Tiktaalik roseae (Amphibian/Fish)

Fossils dated 375 million years old

Transitional FossilsTransitional Fossils

Archaeopteryx lithographica (Bird/Reptile)

Fossils dated 150 million years old

Transitional FossilsTransitional Fossils

Ambulocetus natans called the “walking whale”

Fossils dated ~ 50 million years old

Transitional FossilsTransitional Fossils

Rodhocetus kasrani-extinct whale with mammal characteristics

Fossils dated ~ 46 million years old

Transitional FossilsTransitional Fossils

Basillosaurus cetoides-marine mammal

Fossils dated ~ 40 million years old

Transitional FossilsTransitional Fossils

Physeter macrocephalus Modern sperm whale

Fossils: Common Fossils: Common AncestryAncestry

Darwin found Darwin found fossils of Giant fossils of Giant extinct extinct Armadillos in Armadillos in South America South America that are related to that are related to Modern day Modern day Armadillos. Armadillos.

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BiogeographyBiogeography

Study of the locations of organisms Study of the locations of organisms around the world.around the world.

Example: The Rhea, Ostrich, and Emu are Example: The Rhea, Ostrich, and Emu are similar in size, shape, eating habits, and similar in size, shape, eating habits, and habitat. However each species lives on a habitat. However each species lives on a separate continent. (Convergent Evolution) separate continent. (Convergent Evolution)

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Biogeography Biogeography

Rhea (South America)Rhea (South America)

Ostrich (Africa)Ostrich (Africa)

Emu (Australia) Emu (Australia)

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EmbryologyEmbryology Study of the first stage of developmentStudy of the first stage of development

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Homologous StructuresHomologous Structures

Characteristics that are similar in Characteristics that are similar in structure but different in functionstructure but different in function

Homo = SameHomo = Same

Same evolutionary historySame evolutionary history

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Homologous StructuresHomologous Structures

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BiochemistryBiochemistry

Comparison of DNA or amino acid Comparison of DNA or amino acid sequences over timesequences over time

This is the This is the most powerful most powerful evidence evidence for a common ancestor for a common ancestor

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BiochemistryBiochemistryThe following is a comparison The following is a comparison

of genes in Humans and of genes in Humans and MonkeysMonkeys

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Common Cell ProcessesCommon Cell Processes

Cellular Respiration pathways are Cellular Respiration pathways are similar processes in most speciessimilar processes in most species

Mitosis process is the same in all Mitosis process is the same in all eukaryoteseukaryotes

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Vestigial StructuresVestigial Structures

Structures that have Structures that have lost all or most of lost all or most of their original function their original function in a species through in a species through evolutionevolution

Examples: Mole rat eyes, Manatee fingers, Human Examples: Mole rat eyes, Manatee fingers, Human wisdom teeth, Whale leg bone, Human Appendix wisdom teeth, Whale leg bone, Human Appendix

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Vestigial StructuresVestigial Structures

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AdaptationsAdaptations An inherited trait that is present in a An inherited trait that is present in a

population because the trait helps population because the trait helps individuals survive and reproduce in their individuals survive and reproduce in their environment.environment.

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AdaptationsAdaptations Inuit people, who live in the extreme cold of Inuit people, who live in the extreme cold of

the Arctic, have short, stout bodies that the Arctic, have short, stout bodies that conserve heat. conserve heat.

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AdaptationsAdaptations

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Masai people, who live in the arid lands Masai people, who live in the arid lands of eastern Africa, have tall, lean bodies of eastern Africa, have tall, lean bodies that disperse heat well. that disperse heat well.

AdaptationsAdaptations Venus Fly TrapVenus Fly Trap Lives in poor soil and acquires nutrients Lives in poor soil and acquires nutrients

such as Phosphorus from insectssuch as Phosphorus from insects

Remember thatRemember that Phosphorus isPhosphorus is needed for DNAneeded for DNA

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AdaptationsAdaptations Succulents have thick leaves that store Succulents have thick leaves that store

water to prevent drying outwater to prevent drying out

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AdaptationsAdaptations

Camouflage- blend in with the environmentCamouflage- blend in with the environment

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AdaptationsAdaptations

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AdaptationsAdaptations

Mimicry- mimics or copies characteristics of othersMimicry- mimics or copies characteristics of others

Fly vs Honey Bee Moth vs Bracket Fly vs Honey Bee Moth vs Bracket Fungi Fungi

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AdaptationsAdaptations

King snake vs coral snake Moth Eye Spot vs Owl EyesKing snake vs coral snake Moth Eye Spot vs Owl Eyes

Remember: Red touch Yellow, Kill a Fellow;Remember: Red touch Yellow, Kill a Fellow;

Red touch Black, Good for JackRed touch Black, Good for Jack

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Does Natural Selection Does Natural Selection Occur Now?Occur Now?

Yes, Bacteria reproduce very quicklyYes, Bacteria reproduce very quickly

Over decades of antibiotic use, Over decades of antibiotic use, bacteria have developed resistance to bacteria have developed resistance to antibiotic medicinesantibiotic medicines

Mutations for antibiotic resistance Mutations for antibiotic resistance arise naturally and often in bacteria arise naturally and often in bacteria

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Antibiotic ResistanceAntibiotic Resistance

Today, nearly all bacteria are becoming Today, nearly all bacteria are becoming resistant to one or more antibioticsresistant to one or more antibiotics

As bacteria become resistant, physicians As bacteria become resistant, physicians must switch to using different antibiotics.must switch to using different antibiotics.

Example: Staph infections and Tuberculosis Example: Staph infections and Tuberculosis are both more difficult to treatare both more difficult to treat

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Misconceptions of Misconceptions of EvolutionEvolution

Evolution does not just add Evolution does not just add complexity, it can take it away as wellcomplexity, it can take it away as well

Example: A Tapeworm lacks many organ Example: A Tapeworm lacks many organ systemssystems

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Misconceptions of Misconceptions of EvolutionEvolution

Evolution does not “finish” with a “perfect Evolution does not “finish” with a “perfect trait”trait”

The human eye has a blind spot due to The human eye has a blind spot due to the Optic Nerve the Optic Nerve

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Evolution Can Add Evolution Can Add ComplexityComplexity

Random mutation can lead to more Random mutation can lead to more complex changes complex changes

Example: The icefish is able to withstand the Example: The icefish is able to withstand the Antarctic freeze because it has an Antarctic freeze because it has an antifreeze antifreeze protein protein in its blood that was mutated from the in its blood that was mutated from the typsinogen protein.typsinogen protein.

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2 Subgroups of Evolution2 Subgroups of Evolution

MicroevolutionMicroevolution- refers to evolution as a - refers to evolution as a change in allele frequency in populationschange in allele frequency in populations

MacroevolutionMacroevolution- refers to the appearance of - refers to the appearance of a new species over timea new species over time

The following slides are examples of The following slides are examples of MacroevolutionMacroevolution

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DivergentDivergent Convergent ConvergentEvolutionEvolution EvolutionEvolution

common ancestor

new organisms

different ancestries

some similarities begin to develop in same environment

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See Page 383, Figure 8See Page 383, Figure 8

Adaptive Radiation or Adaptive Radiation or Divergent EvolutionDivergent Evolution

Adaptive Radiation is a special case of divergent evolution - when many niches are filled

Notice that there are 14 species that evolved from the original Finch from South America 5858

Gradualism vs. Gradualism vs. Punctuated EquilibriumPunctuated Equilibrium

Slow, even change Long periods of no change with bursts of rapid change5959

CoevolutionCoevolution

Populations are not isolated, and Populations are not isolated, and often evolve in often evolve in response to each response to each otherother

Coevolution is when 2 species are Coevolution is when 2 species are competing to “one up” each other competing to “one up” each other with adaptationswith adaptations

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CoevolutionCoevolution This moth species and this orchid species have coevolved This moth species and this orchid species have coevolved

is a close relationship. The moth feeds exclusively on the is a close relationship. The moth feeds exclusively on the orchid, and the orchid’s pollen is spread by the moth.orchid, and the orchid’s pollen is spread by the moth.

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Another View of the Moth Another View of the Moth and Orchidand Orchid

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The EndThe End

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