1. 15-3
Evolution in Process

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

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

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

5. 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

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

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

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

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

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

11. 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

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

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