| A | B |
|---|
| artificial selection | breeding organisms with specific traits in order to produce offspring with identical traits |
| natural selection | a mechanism for change in population, occurs when organisms with certain variations survive, reproduce, and pass their variations to the next generation |
| mimicry | a structural adaptation that enables one species to resemble another species |
| camouflage | an adaptation that enables species to blend in with their surroundings |
| homologous structure | structural features with a common evolutionary orgin |
| analogous structure | the body parts of organisms that do not have a common evolutionary orgin but are similiar in function |
| vestigial structure | a body structure that has no function in a present-day organism but was probably useful to an ancestor |
| embryo | earliest stage of growth and development of both plants and animals |
| gene pool | a large pool thatall the alleles of the population's genes are |
| allelic frequency | the percentage of any specific allele in the gene pool |
| genetic equilibrium | a population in which the fequency of alleles remains the same over generations |
| genetic drift | the alteration of allelic frequencies by chance events |
| stabalizing selection | natural selection that favors average individuals in a population |
| directional selection | when natural selection favors one of the extreme variations of the trait |
| disruptive selection | individuals with either extreme of a trait's variation are selected for |
| speciation | the evolution of new species |
| geographic isolation | occurs whenever a physical barrier divides a population |
| reproductive isolation | occurs when formerly interbreeding organisms can no longer mate and produce fertile offspring |
| polyploid | any species with a multiple of the normal set of chromosomes |
| gradualism | the idea that species originate through a gradual change of adaptations |
| punctuated equilibrium | speciation occurs relatively quickly, in rapid bursts with long periods of genetic equilibrium in between |
| adaptive radiation | the result after an ancestral species evolves into an array of species to fit a number of diverse habitats |
| divergent evolution | the pattern of evolution in which species that once were similiar to an ancestral species diverge, or become increasingly distinct |
| convergent evolution | occurs when unrelated species occupy similar enviroments in different parts of the world |
