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30 Cards in this Set
- Front
- Back
adaptive evolution
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increase in frequency of beneficial alleles and decrease in deleterious alleles due to selection |
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allele frequency
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rate at which a specific allele appears within a populatio; also known as gene frequency |
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bottleneck effect
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magnification of genetic drift as a result of natural events or catastrophes |
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cline
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gradual geographic variation across an ecological gradient |
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directional selection
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selection that favors phenotypes at one end of the spectrum of existing variation |
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diversifying selection
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selection that favors two or more distinct phenotypes |
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evolutionary fitness
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individual’s ability to survive and reproduce; also known as Darwinian fitness |
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founder effect
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event that initiates an allele frequency change in part of the population, which is not typical of the original population |
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frequency-dependent selection
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selection that favors phenotypes that are either common (positive frequency-dependent selection) or rare (negative frequency-dependent selection) |
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gene flow
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flow of alleles in and out of a population due to the migration of individuals or gametes gene pool all of the alleles carried by all of the individuals in the population |
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genetic drift
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effect of chance on a population’s gene pool |
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genetic structure
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distribution of the different possible genotypes in a population |
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genetic variance
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diversity of alleles and genotypes in a population |
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geographical variation
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differences in the phenotypic variation between populations that are separated geographically |
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good genes hypothesis
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theory of sexual selection that argues individuals develop impressive ornaments to show off their efficient metabolism or ability to fight disease |
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handicap principle
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theory of sexual selection that argues only the fittest individuals can afford costly traits |
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heritability
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fraction of population variation that can be attributed to its genetic variance |
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inbreeding depression
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increase in abnormalities and disease in inbreeding populations |
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modern synthesis
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overarching evolutionary paradigm that took shape by the 1940s and is generally accepted today |
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nonrandom mating
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changes in a population’s gene pool due to mate choice or other forces that cause individuals to mate with certain phenotypes more than others |
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population genetics
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study of how selective forces change the allele frequencies in a population over time |
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population variation
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distribution of phenotypes in a population |
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relative fitness
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individual’s ability to survive and reproduce relative to the rest of the population |
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honest signal |
trait that gives a truthful impression of an individual’s fitness |
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inbreeding |
mating of closely related individuals |
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macroevolution |
broader scale evolutionary changes seen over paleontological time |
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microevolution |
changes in a population’s genetic structure |
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selective pressure |
environmental factor that causes one phenotype to be better than another |
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sexual dimorphism |
phenotypic difference between the males and females of a population |
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stabilizing selection |
selection that favors average phenotypes |