Evidence of evolutionEvidence of evolution• Fossil RecordFossil Record

• Fossil-Fossil-– Organism or Organism or

evidence of an evidence of an organism organism preserved in rockpreserved in rock

Fossil formationFossil formation• Sedimentary rockSedimentary rock• SuperpositionSuperposition

– Older fossils are Older fossils are found in lower found in lower layers of rocklayers of rock

– Younger fossils in Younger fossils in upper layersupper layers

• AmberAmber

Geologic Time ScaleGeologic Time Scale• A time frame based A time frame based

on the fossil recordon the fossil record• Eras (4)Eras (4)

– CenozoicCenozoic– MesozoicMesozoic– PaleozoicPaleozoic– PrecambrianPrecambrian

• PeriodsPeriods• EpochsEpochs

DatingDating• Determining the Determining the

age of rock and age of rock and fossilsfossils

• Relative ageRelative age– Used to determine Used to determine

the relative agethe relative age– Compare layers of Compare layers of

rockrock

DatingDating• Absolute datingAbsolute dating• (radioactive dating)(radioactive dating)

– Used to determine the Used to determine the actual dateactual date

– Uses the half life to Uses the half life to determine actual agedetermine actual age

– Half life- time needed for Half life- time needed for half the radioactive half the radioactive atoms in a sample to atoms in a sample to decaydecay• Carbon-14= 5,770 yrsCarbon-14= 5,770 yrs• Uranium-238= 4.5 billion Uranium-238= 4.5 billion

yrsyrs

Other evidence showing Other evidence showing relationshipsrelationships

• Comparative Comparative anatomyanatomy– Homologous Homologous

structuresstructures– Vestigial structuresVestigial structures

• Comparative Comparative embryologyembryology

• Comparative Comparative biochemistrybiochemistry

Evolution in ActionEvolution in Action• Caribbean Anole Caribbean Anole

LizardsLizards• 3 species3 species• On tree trunks & On tree trunks &

groundground• On tree branchesOn tree branches• On grassOn grass

Evolution in ActionEvolution in Action• Other Islands show Other Islands show

similar body types similar body types in other species of in other species of lizardlizard

• Convergent Convergent EvolutionEvolution– Process where Process where

different species different species evolve similar traitsevolve similar traits

Evolution in ActionEvolution in Action• Divergent Divergent

EvolutionEvolution– Process in which Process in which

the descendants of the descendants of a single ancestor a single ancestor evolve into species evolve into species that fit different that fit different parts of the parts of the environmentenvironment

Evolution in ActionEvolution in Action• Adaptive RadiationAdaptive Radiation

– Species undergo Species undergo divergent evolution divergent evolution until many parts of until many parts of the environment the environment are filledare filled

– Ex. Darwin’s Ex. Darwin’s FinchesFinches