17 lines
1.2 KiB
Markdown
17 lines
1.2 KiB
Markdown
[[Unit 3 (TBD)]]
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Natural selection is situational. It requires heritable variation, competition, and selective pressures.
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==Selective pressure== are environmental conditions pressuring traits.
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==Selective advantage== is a genetic advantage.
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Sexual selection is mate selection for a particular phenotype. It may affect fitness.
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Females choose their mates.
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Good genes hypothesis: Females choose mates on traits that improve chance of survival.
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Runaway hypothesis: Females choose on basis of traits that improve male appearance.
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Sexual dimorphism: Different characteristics between male and females to the point that they appear to be separate species.
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Intersexual selection: Females choose mates based on appearance/phenotype/behavior.
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Intrasexual selection: Competition between the same sex of same species to pass on DNA.
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Stabilizing selection: The intermediate phenotype is favored.
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Directional selection: Favors phenotypes at an extreme of the range, resulting in the curve being shifted towards that extreme.
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Disruptive selection: Both extremes are favored at the same time. Can eliminate the intermediate phenotype, resulting in speciation.
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