Evidence of Evolution

1. Evidence of Evolution Blue-footed booby

2. Evidence of evolution • Fossil Record • Anatomy • Embryology • Biochemistry • Evidence in microevolution

3. Fossil evidence Mold Fossil • Fossils → remains of ancient life • Fossils arranged according to age show a progression of changes • The Law of Superposition → a layer of rock is older than the layer above • Fossils can be arranged by relative age • Radioactive Dating→ naturally occurring radioactive substances decay at a known rate • Transitional forms of fossils are evidence for evolutionary change Preservation (insect in amber) Cast Fossil

6. Anatomy evidence • Evolution works primarily by modifying pre-existing structures • Homologous structures: parts came from the same origins, but now may have different function • e.g., forelimbs of all mammals contain the same pattern of bones, although the bones now carry out a variety of functions • horse leg, bat wing, human arm, whale flipper

8. Anatomy evidence • Analogous structures: parts came from different origin, but now have same function

9. Anatomy evidence • Vestigial structures: parts have no current function (had a function in ancestors) • Examples in humans: wisdom teeth, erector pili, coccyx, ear muscles, appendix

12. Embryology evidence • Closely related organisms develop similarly, especially in early fetal stages • This suggests that these organisms are related to other forms. • Mammal embryos (including humans) have fish-like gill slits, tail

17. Biochemistry evidence • All organisms share certain biochemistry • Genetic code for building amino acids • All organisms use ATP for energy • Plasma membranes of all organisms consist of a phospholipid bi-layer

18. # of amino acid differences between human hemoglobin and other organisms

20. H: Human Chromosome C: Chimp Chromosome

21. Evidence for Microevolution Evolution Observed Evolution of pesticide resistance in response to selection.

22. Evidence for Evolution – Evolution Observed Evolution of drug-resistance in HIV

24. Evolution in Action

25. Macroevolution Large scale changes that take place over a long period of time that create and eliminate species.

26. Microevolution Short time scale events (generation-to-generation) that change the genotypes and phenotypes of populations.