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module 14 vocab
Question | Answer |
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artificial selection | Darwin's term for the selective breeding of organisms selected for certain traits in order to produce offspring having those traits |
natural selection | theory of evolution developed by Darwin, based on four ideas: excess reproduction, variations, inheritance, and the advantages of specific traits in an environment |
evolution | hereditary changes in groups of living organisms over time |
derived trait | new feature that had not appeared in common ancestors |
ancestral trait | more-primitive characteristic that appeared in common ancestors |
homologous structure | anatomically similar structure inherited from a common ancestor |
vestigial structure | reduced from of a functional structure that includes shared ancestry |
embryo | organism's early prebirth stage of development |
biogeography | study of the distribution of plants and animals |
fitness | measure of a trait's relative contribution to the following generation |
camouflage | morphological adaptions that allow organisms to blend into their surroundings |
mimicry | morphological adaptions in which one species evolves to resemble another species for protection or other advantages |
hardy-Weinberg principle | states that allelic frequencies in populations stay the same unless they are affected by a factor that causes change |
genetic drift | random change in allelic frequencies in a population |
founder effect | random effect that can occur when a small population settles in an area separated from the rest of the population and interbreeds, producing unique allelic variations |
bottleneck | process in which a large population declines in number, then rebounds |
stabilizing selection | most common form of natural selection in which organisms with extreme expressions of a trait are removed |
directional selection | shift of a population toward an extreme version of a beneficial trait |
disruptive selection | process in which individuals with average traits are removed, creating two populations with extreme traits |
sexual selection | change in the frequency of a trait based on competition for a mate |
prezygotic isolating mechanism | factor that prevents individuals from different species before fertilization |
postzygotic isolating mechanism | factor that prevents a hybrid zygote from developing, or prevents hybrid offspring from reproducing; operates after fertilization |
allopatric speciation | occurs when a population divided by a geographic barrier evolves into tow or more populations unable to interbreed |
sympatric speciation | occurs when a species evolves into a new species in an area without a geographic barrier |
adaptive radiation | diversification of a species into a number of different species, often over a relatively short time span |
gradualism | theory that evolution occurs in small, gradual steps over time. |
punctuated equilibrium | theory that evolution occurs with relatively sudden periods of speciation followed by long periods of stability |