Concept 51 - Concept 51.5 Natural selection favors...

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Concept 51.5 Natural selection favors behaviors that increase survival and reproductive success The genetic components of behavior evolve through natural selection favoring traits that  enhance survival and reproductive success in a population. Two of the most direct ways that behavior can affect fitness are through influences on  foraging and mate choice. Foraging includes not only eating, but also any mechanisms that an animal uses to  recognize, search for, and capture food items. Optimal foraging theory  views foraging behavior as a compromise between the benefits  of nutrition and the costs of obtaining food, such as the energy expenditure and risk of  predation while foraging. Natural selection should favor foraging behavior that minimizes the costs of foraging and  maximizes the benefits. Behavioral ecologists apply cost-benefit analysis to study the proximate and ultimate causes  of diverse foraging strategies. Reta Zach of the University of British Columbia carried out a cost-benefit analysis of  feeding behavior in crows. Crows search the tide pools of Mandarte Island, B.C., for snails called whelks. A crow flies up and drops the whelk onto the rocks to break its shell. If the drop is successful, the crow eats the snail’s soft body. If it is not successful, the crow flies higher and tries again. Zach predicted—and found—that crows would, on average, fly to a height that would  provide the most food relative to the total amount of energy required to break the whelk  shells.
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Concept 51 - Concept 51.5 Natural selection favors...

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