15-3 Evolution in Process

Evidence of Evolution 1. Homologous Structures 2. Analogous Structures 3. Vestigial Structures 4. Similarities in Embryology 5. Similarities in Macromolecules

1. Homologous Structures Similar features that originated in common ancestor (recent) Ex: human arm, bird wing, frog arm

2. Analogous Structures Features which share a purpose but do not have common origin Ex: bird wing insect wing

3. Vestigial Structures Features which were useful to an ancestor but have no current use Ex: Human tail bone, appendix Snake pelvic bones limb bones Whale pelvic bones

4. Similarities in Embryology “Ontogeny recapitulates phylogeny” Embryological development repeats evolutionary history Ernst Haeckel

5. Similarities in Macromolecules Amino acid sequence (proteins) Ex cytochrome C The more similarities = the more recent common ancestor

Patterns of Evolution Ways in Which Species Change 1. Coevolution 2. Convergent evolution 3. Divergent evolution

1. Coevolution Change of 2 or more species in close association with each other Ex predator/prey flowers/pollinators

2. Convergent Evolution Occurs when similar phenotypes in different species are selected in similar environment even though ancestors were very different Ex shark & porpoise

3. Divergent Evolution Occurs when 2 or more related populations or species become more & more different (usually due to habitat changes) 2 types Adaptive radiation Artificial selection

Adaptive Radiation Many species from single common ancestor Ex Darwin’s finches

Artificial Selection Selective breeding Ex dogs, cats, horses, sheep, chickens, fruit