Question | Answer |
immigration | the movement of an individual or a group to a new community or region |
emigration | the movement of an individual or group out of its native area |
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 |
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; selection in which a mate is chosen on the basis or a particular trait or traits |
stabilizing selection | a type of natural selection in which the average form of a trait is favored and becomes more common |
disruptive selection | individuals with either extreme variation of a trait have greater fitness than individuals with the average form of the trait |
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 |
microevolution | evolution at the genetic level |
population genetics | the study of the frequency and interaction or alleles and genes in populations |
bell curve | a symmetrical frequency curve |
gene pool | all of the genes of the reproductively active members of a population |
allele frequency | the proportion of gene copies in a population that are a given allele, expressed as a percentage |
phenotype frequency | is equal to the number of individuals with a particular phenotype divided by the total number of individuals in the population |
Hardy-Weinberg genetic equilibrium | a principle based on a set of assumptions about an ideal hypothetical population that is not evolving |
speciation | the formation of new species as a result of evolution |
morphology | the study of the structure and form of an organism |
biological species concept | the principle that defines a species as a group of organisms whose members can interbreed to produce offspring |
geographic isolation | the physical separation of populations due to geographic barriers that prevent interbreeding |
allopatric speciation | happens when species arise as a result of geographic isolation |
reproductive isolation | the inability of members of a population to successfully interbreed with members of another population of the same or related species |
prezygotic isolation | type of reproductive isolation; occurs before fertilization |
postzygotic isolation | type of reproductive isolation; occurs after fertilization |
sympatric speciation | occurs when 2 subpopulations become reproductively isolated within the same geographical area |
gradualism | a model or evolution in which gradual change over a long period of time leads to biological diversity |
punctuated equilibrium | a model of evolution in which short periods of drastic change in species, including mass extinction and rapid speciation, are separated by long periods of little or no change |