| A | B |
|---|
| natural selection | organisms with favorable traits survive and reproduce |
| adaptation | an inherited trait that increases an organism's chance of survival |
| variation | differences between organisms |
| homologous structure | similar features that originated in a shared ancestor; |
| Example of homologous structure | bird wings and human arms |
| analogous structure | have same function but different origin |
| Ex. of analogous structure | bird wings & butterfly wings |
| vestigial structure | features useful to our ancestors but not to us |
| Ex. of vestigial structure | appendix, tailbone |
| divergent evolution | process of two or more related species becoming more and more dissimilar (homologous structures develop) |
| convergent evolution | the process by which unrelated species become more similar as they adapt to the same kind of environment (analagous structures develop) |
| artificial selection | breeding of organisms by humans for specific phenotypic characteristics |
| adaptive radiation | many related species evolve from a single ancestral species (type of divergent evolution) |
| coevolution | change of 2 or more species in close association with each other |
| evidence for evolution | fossil,macromolecules,homologous, analagous, vestigial,embryology |
| gene pool | Total genetic information available to a population |
| directional selection | individuals with a more extreme form of a trait have greater fitness |
| stabelizing selection | Individuals with the average form of a trait have the highest fitness |
| disruptive selection | Individuals with either extreme variation have greater fitness than the average form |
| punctuated equilibrium | Evolution occurs in a few thousand rather than a few million years |
