Evidence of Evolution. 1.Fossil Record 2.Homologous Body structures 3.Similarities in Embryology 4.Biochemical Evidence.

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Evidence of Evolution

Evidence of Evolution

Evidence of EvolutionFossil RecordHomologous Body structures

Similarities in Embryology Biochemical EvidenceEvidence of Evolution:The Fossil RecordFossil record provides evidence that living things have evolved

Fossils show the history of life on earth and how different groups of organisms have changed over time

Relative vs. Absolute Dating

Relative DatingCan determine a fossils relative agePerformed by estimating fossil age compared with that of other fossilsDrawbacks provides no info about age in years

Absolute DatingCan determine the absolute age in numbersIs performed by radioactive dating based on the amount of remaining radioactive isotopes remainDrawbacks - part of the fossil is destroyed during the test

A half-life is the amount of time it takes for half of the isotope to decay.Radiometric dating uses decay of unstable isotopes.Isotopes are atoms of an element that differ in their number of neutrons.

7Primate Fossils

AustralopithecusHomo erectusHomo sapienPrimate Bone Structure

Evidence of Evolution:Homologous Body Structures

Structures that have different mature forms but develop from the same embryonic tissues

Ex: Wing of bat, human arm, leg of turtle

TurtleAlligatorBirdEvidence of Evolution:Homologous StructuresFeatures that are similar in structure but appear in different organisms and have different functions.Strong evidence for common ancestor.Ex: forelimbs of humans, bats and moles.

Human handBat wingMole foot11Analogous StructuresStructures that perform a similar function.Not evidence of common ancestry.

12

Vestigial StructuresRemnants of organs or structures that had a function in an early ancestor.Ex: Ostrich wings, used for balance but not flightEx: Humans appendix13Evidence of Evolution:Similarities in EmbryologyIn their early stages of development, chickens, turtles and rats look similar, providing evidence that they shared a common ancestry.

Embryological Development

Evidence of Evolution:Biochemical SimilaritiesScientists study nucleotide sequences in DNA and proteins in different organisms to determine ancestry.If the organisms are closely related they will have similar sequences of nucleotides in their DNA and arrangement of amino acids in proteins.Evidence of Evolution:Biochemical SimilaritiesOrganismAmino Acid DifferencesOrganismAmino Acid DifferencesHuman beta chain0Mouse27Gorilla1Kangaroo38Rhesus monkey8Chicken45Dog15Frog67Cow25Soy bean124The more similar the amino acid sequence, the more closely related the organisms are.

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