CHDV 23249 Chapter Notes - Chapter 1: Physalaemus, Xiphophorus, Fred Basolo
23 Jan 2017
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Document Summary
Female preference predates the evolution of the sword in swordtail fish. Evolution of male traits swordless platyfish and swordtails. This study found that female platyfish prefer conspecific males with artificial swords over those without swords. Results suggest that evolution of sword in swordtail clade was a result of selection arising from preexisting bias. Proposed by darwin as a mechanism to explain evolution of elaborate traits in males (that decrease their survival) One type of sexual selection: female choice: preference by females for traits in males, explanation for this: biases in female sensory/cognitive systems arise and increase to a high frequency for reasons independent of sexual selection. In males, evolution of traits occurs when a new trait exploits preexisting bias in females. Already present in females before appearance of male trait. Preexisting bias model does not require female preference to evolve, nor coevolution of the preference and trait.
