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Chapter 11
Term | Definition |
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gene pool | the total set of genes, including all alleles, that are present in a population at any one point in time |
allele frequency | proportion of one allele, compared with all the alleles for that trait, in a gene pool |
normal distribution | a distribution of numerical data whose graph forms a bell-shaped curve that is symmetrical about the mean |
microevolution | observable change in the allele frequencies of a population over a few generations |
directional selection | a natural selection process in which one genetic variation is selected and that causes a change in the overall genetic composition of the population |
stabilizing selection | a type of natural selection in which the average form of a trait is favored and becomes more common |
disruptive selection | a type of natural selection in which two extreme forms of a trait are selected |
gene flow | the movement of genes into or out of a population due to interbreeding |
genetic drift | the random change in allele frequency in a population |
bottleneck effect | genetic drift that results from an event that drastically reduces the size of a population |
founder effect | genetic drift that occurs after a small number of individuals colonize a new area |
sexual selection | an evolutionary mechanism by which traits that increase the ability of individuals to attract or acquire mates appear with increasing frequency in a population |
Hardy-Weinberg equilibrium | condition in which a population's allele frequencies for a given trait do not change from generation to generation |
reproductive isolation | a state in which a particular set of populations can no longer interbreed to produce future generations of offspring |
speciation | the formation of new species as a result of evolution |
behavioral isolation | isolation between populations due to differences in courtship or mating behavior |
geographic isolation | isolation between populations due to physical barriers |
temporal isolation | isolation between populations due to barriers related to time, such as differences in mating periods or differences in the time of the day that individuals are most active |
Convergent evolution | the process by which unrelated species become more similar as they adapt the the same kind of environment |
divergent evolution | evolution of one or more closely related species |
coevolution | the evolution of two or more species that is due to mutual influence often in a way that makes the relationship more mutually beneficial |
extinction | the death of every member of a species |
punctuated equilibrium | a model of evolution in which short periods of drastic change in a species, including mass extinctions and rapid speciation, are separated by long periods of little to no change |
adaptive radiation | an evolutionary pattern in which many species evolve from a single ancestral species |