| A | B |
|---|
| camouflage | a structural adaptation that enables an organism to blend in with its surroundings |
| mimicry | a structural adaptation that provides protection for an organism by copying the appearance of another species |
| homologous structure | modified structure seen among different groups of descendents |
| analogous structure | any body structure that is similar in function but different in structure |
| vestigial structure | any body structure that is reduced in function in a living organism but may have been used in an ancestor |
| gene pool | the entire collection of genes among a population |
| genetic drift | alteration of allelic frequencies by chance processes |
| directional selection | one of the extreme forms of a trait is favored by natural selection |
| disruptive selection | individuals with both extreme forms of a trait are at a selective advantage |
| stabilizing selection | type of natural selection that favors average individuals in a population |
| speciation | evolution of a new species |
| geographic isolation | when a physical barrier separates a population into groups |
| reproductive isolation | when formerly interbreeding organisms are prevented from producing fertile offspring |
| gradualism | the idea that species originate through a gradual buildup of new adaptations |
| adaptive radiation | process of evolution of an ancestral species into an array of species that occupy different niches |
| divergent evolution | pattern of evolution in which species once all similar to ancestral species become more and more distinct |
| convergent evolution | pattern of evolution in which distantly related organism evolve similar traits |
