Term
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Definition
| The percentage, on average, of a population's loci that are heterozygous in members of the population. |
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Term
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Definition
| Natural selection that maintains two or more phenotypic forms in a population. |
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Term
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Definition
| Genetic drift that occurs when the size of a population is reduced, as by a natural disaster or human actions. Typically, the surviving population is no longer genetically representative of the original population. |
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Term
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Definition
| A graded change in a character along a geographic axis. |
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Term
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Definition
| Natural selection in which individuals at one end of the phenotypic range survive or reproduce more successfully than do other individuals. |
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Term
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Definition
| Natural selection in which individuals on both extremes of a phenotypic range survive or reproduce more successfully than do individuals with intermediate phenotypes. |
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Term
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Definition
| Genetic drift that occurs when a few individuals become isolated from a larger population and form a new population whose gene pool composition is not reflective of that of the original population. |
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Term
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Definition
| The transfer of alleles from one population to another, resulting from the movement of fertile individuals or their gametes. |
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Term
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Definition
| The aggregate of all copies of every type of allele at all loci in every individual in a population. The term is also used in a more restricted sense as the aggregate of alleles for just one or a few loci in a population. |
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Term
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Definition
| A process in which chance events cause unpredictable fluctuations in allele frequencies from one generation to the next. Effects of genetic drift are most pronounced in small populations. |
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Term
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Definition
| Differences among individuals in the composition of their genes or other DNA segments. |
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Term
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Definition
| Differences between the gene pools of geographically separate populations or population subgroups. |
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Term
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Definition
| The principle that frequencies of alleles and genotypes in a population remain constant from generation to generation, provided that only Mendelian segregation and recombination of alleles are at work. |
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Term
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Definition
| Greater reproductive success of heterozygous individuals compared with homozygotes; tends to preserve variation in a gene pool. |
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Term
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Definition
| Selection whereby individuals of one sex (usually females) are choosy in selecting their mates from individuals of the other sex; also called mate choice. |
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Term
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Definition
| Selection in which there is direct competition among individuals of one sex for mates of the opposite sex. |
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Term
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Definition
| Evolutionary change below the species level; change in the allele frequencies in a population over generations. |
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Term
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Definition
| Genetic variation that does not provide a selective advantage or disadvantage. |
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Term
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Definition
| A group of individuals of the same species that live in the same area and interbreed, producing fertile offspring. |
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Term
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Definition
| The contribution an individual makes to the gene pool of the next generation, relative to the contributions of other individuals in the population. |
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Term
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Definition
| Differences between the secondary sex characteristics of males and females. |
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Term
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Definition
| A form of selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates. |
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Term
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Definition
| Natural selection in which intermediate phenotypes survive or reproduce more successfully than do extreme phenotypes. |
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