Animal Behavior

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Genetic components of behavior evolve through natural selection.

Behavior can affect fitness by influencing foraging and mate choice.

Natural selection refines behaviors that enhance the efficiency of feeding.

Foraging = food-obtaining behavior. Foraging includes recognizing, searching for, capturing, and eating food items.

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Optimal Foraging Model

Optimal foraging model views foraging behavior as a compromise between benefits of nutrition and costs of obtaining food.

The costs of obtaining food include energy expenditure and the risk of being eaten while foraging.

Natural selection should favor foraging behavior that minimizes the costs and maximizes the benefits.

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Balancing Risk and Reward

Risk of predation affects foraging behavior.

For example, mule deer are more likely to feed in open forested areas where they are less likely to be killed by mountain lions.

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Mating Behavior and Mate Choice

Mating behavior includes seeking or attracting mates, choosing among potential mates, and competing for mates.

Mating behavior results from a type of natural selection called sexual selection.

The mating relationship between males and females varies greatly from species to species.

In many species, mating is promiscuous, with no strong pair-bonds or lasting relationships.

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In monogamous relationships, one male mates with one female.

Males and females with monogamous mating systems have similar external morphologies.

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Relationship between mating system

and

male and female

forms.

(a) Monogamous species

(b) Polygynous species

(c) Polyandrous species

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In polygamous relationships, an individual of one sex mates with several individuals of the other sex.

Species with polygamous mating systems are usually sexually dimorphic: males and females have different external morphologies.

Polygamous relationships can be either polygynous or polyandrous. In polygyny - one male mates with many females. The males are usually more showy and larger than the females.

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Fig. 51-20b

Polygynous species – Male larger and more dominant

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In polyandry = one female mates with many males.