Evidence for Evolution By Diana L. Duckworth Rustburg High School Campbell County

Comparative Anatomy Evidence of common ancestry – same groups of bones. Homologous Structures 1_1/analogous_and_homologous_structures.html

Vestigial Structures Homologous bones or organs that are no longer functional Humans – cocyx (tail bone); appendix; ear muscles; wisdom teeth; body hair; eyebrows; eye lashes; tonsils

Homologous Embryology Early development is same for many organisms; evidence of common ancestry.

Fossil Evidence Excellent lineages of –Horses –Pigs –Whales Two types of patterns visible: –Gradualism – directional selection produces gradual change over long time period –Punctuated Equilibrium – rapid evolution in short bursts separated by long periods of stasis Rapid evolution – directional or disruptive selection Stasis – stabilizing selection

Horse evolutionWhale evolution

From one Class to Another Mammal, adapted for chewing & tearing Mammal-like reptile Reptile, adapted for gulping Note differences in body position

From a reptilian skull to a mammal- like reptile to a mammalian skull; well documented transitions in fossil record.

Mammal-like reptiles;body Type – reptile; skull mammalian Internal structure of bones indicative of endothermy – warm blooded.