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18 Cards in this Set
- Front
- Back
- 3rd side (hint)
microevolution
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change in allele frequencies in a population over generations
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three mechanisms that alter allele frequency and bring about most evolutionary change:
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1. natural selection (good change)
2. generic drift 3. gene flow |
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generic variation
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is caused by differences in genes or other DNA segments
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average heterozygosity
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measures the average percent of loci that are heterozygous in a population
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sources of genetic variation:
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1. formation of new alleles
2. altering gene number or position 3. rapid reproduction 4. sexual reproduction |
four kinds
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Hardy-Weinberg
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describes a population that is NOT evolving
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frequency of an allele in a population
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p + q = 1
p = % homozygous dominant allele q = % homozygous recessive allele |
equation
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frequency of individual genotypes
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p² + 2pq + q² = 1
p² = % homozygous dom. genotype 2pq = % heterozygous genotype q² = % homozygous rec. genotype |
equation
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conditions for Hardy-Weinberg equilibrium
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1. no mutation
2. random mating 3. no natural selection 4. large population 5. no gene flow |
five conditions
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genetic drift
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describes how allele frequencies fluctuate unpredictably from one generation to another
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founder effect
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occurs when a few individuals become isolated from a larger population
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one form of genetic drift
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bottleneck effect
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a sudden reduction in population size due to a change in the environment.
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one form of genetic drift
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gene flow
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movement of alleles among populations
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reduces variation
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three modes of selection
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1. directional
2. disruptive 3. stabilizing |
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sexual selection
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natural selection for mating success
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sexual dimorphism
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marked differences between the sexes in secondary characteristics
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peacocks
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intrasexual selection
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competition of one sex (often males) for mates of the opposite sex
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good kind
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intersexual selection
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often called mate choice, individuals of one sex (females) are choosy in selecting mates
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double edged sword
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