Concept 40.1   Behavior Is Controlled by the Nervous System but Is Not Necessarily Deterministic

• Changes in behavior are an important way for animals to respond to changes in their environment. Review Figure 40.1
• An animal’s behaviors are activated and coordinated by the animal’s nervous system.
• Some animal behaviors, called fixed action patterns, are highly stereotyped. They do not require learning and in fact are often resistant to modification by learning. Review Figure 40.2
• Animal behavior has a genetic basis and is subject to natural and artificial selection. Behavior therefore evolves. Review Figure 40.3
• Behavior is often flexible; it can be modified by an animal’s experiences.

Concept 40.2   Behavior Is Influenced by Development and Learning

• Many animals are able to learn—meaning that individuals can alter their behaviors on the basis of previous individual experiences.
• Behavioral imprinting is a process by which an animal learns to respond to a specific set of stimuli during a limited period early in postnatal life and thereafter the behavioral responses are fixed.
• Early experiences can affect the behavior of an animal for the remainder of its life. Some of these effects are consequences of epigenetic effects on gene expression.

Concept 40.3   Behavior Is Integrated with the Rest of Function

• Behavior and other aspects of animal function are interdependent; the behavior of an animal is constrained by its physiological capacity to perform the required actions.
• Body structure, size, and growth rate can influence behavior, as can cellular biochemistry and metabolism. Review Figure 40.7

Concept 40.4   Moving through Space Presents Distinctive Challenges

• Animals find their way in the environment by navigation (moving toward a particular destination or along a particular course) and orientation (adopting a position or trajectory relative to an environmental cue).
• Animals sometimes navigate by following trails, which in many cases are marked with pheromones. Navigation may also involve path integration. During this process, an animal integrates the distances and directions it travels to maintain an awareness of its position relative to a particular site. Review Figure 40.8 and Figure 40.9
• Animals may sense direction by using information on the sun, magnetic fields, landmarks, and atmospheric polarization patterns. A sun compass involves not only observing the sun’s position but also knowing the time of day, information that can be provided by a circadian biological clock. Animals often have multiple, redundant mechanisms of orientation. Review Figure 40.10 and ANIMATED TUTORIAL 40.1 and ANIMATED TUTORIAL 40.2
• Honey bees use a waggle dance to communicate the position of a food source relative to the hive. Review Figure 40.11 and ACTIVITY 40.1
• Some animals display remarkable feats of navigation when they migrate, traveling as far as thousands of kilometers between locations. Review Figure 40.12

Concept 40.5   Social Behavior Is Widespread

• A society is a group of individuals of a single species that exhibits some degree of cooperative organization.
• Group living confers benefits such as greater foraging efficiency and protection from predators, but it also has costs, such as increased competition for food and ease of transmission of diseases. Review Figure 40.13 and Figure 40.14
• Individuals in a society can be of equal status—as in a school of fish—or of unequal status—as in a group of impala antelopes. In some cases a single male dominates the other males in a group; this usually confers a reproductive advantage on the dominant male.
• An extreme form of unequal status is seen in cases of eusociality, in which some individuals in the group are infertile and assist the reproduction of fertile individuals, usually their mother and a few male siblings. Eusocial animals include the social insects (e.g., honey bees) and naked mole rats.

Concept 40.6   Behavior Helps Structure Ecological Communities and Processes

• Behavioral differences help maintain species by decreasing the likelihood of interspecies breeding.
• An individual within a population often restricts its movements to a limited portion of the area occupied by the population as a whole. The smaller area is known as a territory if the individual actively keeps out other individuals of the same species, or as a home range if other individuals are not excluded. Review Figure 40.16 and ANIMATED TUTORIAL 40.3
• A cost–benefit approach can be used to investigate the adaptive value of specific behaviors. Review ANIMATED TUTORIAL 40.4

See ACTIVITY 40.2 for a concept review of this chapter.