Happy Tuesday!Happy Tuesday!

Lets do a QuickwriteLets do a Quickwrite

1. List the 5 requirements for 1. List the 5 requirements for Natural Selection to occur.Natural Selection to occur.

Over productionOver production VariationVariation Struggle to surviveStruggle to survive Survival of fittestSurvival of fittest Populations evolvePopulations evolve

Evidence Supporting Evidence Supporting EvolutionEvolution

EEven ven VVery ery GGood ood FFriends riends HHiccupiccupEmbryonic, Vestigial, Genetics, Fossils, Embryonic, Vestigial, Genetics, Fossils,

Homologous structuresHomologous structures

1. Embryonic Similarites1. Embryonic Similarites The same groups of cells develop in the same The same groups of cells develop in the same

order and in similar patterns in all vertebratesorder and in similar patterns in all vertebrates..

The more alike the embryo stages are, the The more alike the embryo stages are, the more closely related the organisms are more closely related the organisms are thought to be.thought to be.

Examples: Turtles, chickens, rabbits, and Examples: Turtles, chickens, rabbits, and humans all appear similar as embryos!humans all appear similar as embryos!

1. Embryonic Similarities1. Embryonic Similarities

2. Vestigial Structures2. Vestigial Structures

Structures in organisms left over from Structures in organisms left over from ancestors that have no known functionsancestors that have no known functions..

Examples:Examples: Leg bones in skinksLeg bones in skinks Appendix in humansAppendix in humans Tailbone in humansTailbone in humans

Legless SkinkLegless Skink

3. Comparative Anatomy3. Comparative Anatomy The study of the structures of different The study of the structures of different

organismsorganisms

Homologous StructuresHomologous Structures

Anatomy that is similar in structure and Anatomy that is similar in structure and originorigin

Not always similar in functionNot always similar in function This shows an evolutionary relationshipThis shows an evolutionary relationship

Examples: Examples: Fore-limbs of whales, birds, Fore-limbs of whales, birds, cats, and humans have similar bone cats, and humans have similar bone structuresstructures

Homologous StructuresHomologous Structures

Analogous StructuresAnalogous Structures

Structures that perform the same function Structures that perform the same function but have different anatomybut have different anatomy

This shows NO EVOLUTIONARY This shows NO EVOLUTIONARY RELATIONSHIPRELATIONSHIP

Example: Example: The wings of birds and The wings of birds and butterfliesbutterflies

Analogous StructuresAnalogous Structures

4. Fossil Record4. Fossil Record Shows extinct species that have similar Shows extinct species that have similar

structures to those alive todaystructures to those alive today Includes hundreds of transitional fossils that Includes hundreds of transitional fossils that

demonstrate intermediate stages in evolutiondemonstrate intermediate stages in evolution

ExamplesExamples Giant armadillos and slothsGiant armadillos and sloths CephalopodsCephalopods

Giant Armadillo and SlothGiant Armadillo and Sloth

How did this whole thing happen?How did this whole thing happen? PangeaPangea

The idea that our earth was once one huge The idea that our earth was once one huge planet that split apart and became the 7 planet that split apart and became the 7 continents we know today.continents we know today.

5. Genetic Similarities5. Genetic Similarities(Biochemical Homology)(Biochemical Homology)

Related organisms have closely related Related organisms have closely related DNA sequences and amino acid sequencesDNA sequences and amino acid sequences

This comparison tends to be more reliable This comparison tends to be more reliable than anatomical studiesthan anatomical studies

Examples: Examples: Human and chimpanzee DNA Human and chimpanzee DNA are 98% similarare 98% similar

Genetic SimilaritiesGenetic Similarities