Behavioral responses to stimuli may be adaptive

Animals perform behaviors whose benefits outweigh their costs.

• Behaviors evolve only if they improve fitness.
• Territoriality refers to the control of a specific area.
• benefits: control resources
• costs: energy and time

• Optimal foraging states that natural selection favors behaviors that get animals the most calories for the cost.

• benefits: amount of energy gained
• costs: energy used to search for, catch, and eat food; risk of capture; time

• KEY CONCEPT Social behaviors enhance the benefits of living in a group.

Living in groups also has benefits and costs.

• Social behaviors evolve when the benefits of group living outweigh its costs.

• benefits: improved foraging, reproductive assistance, reduced chance of predation
• costs: increased visibility, competition, disease contraction

• Group living requires learning social structure and membership.

Social behaviors are interactions between members of the same or different species.

• Animals use communication to keep in contact.
• visual
• sound
• touch
• chemical

• Courtship displays are used to evaluate the fitness of a potential mate.

• Defensive behaviors are used to protect the individual and/or the group.

Some behaviors benefit other group members at a cost to the individual performing them.

• There are many types of helpful social behavior.
• cooperation

• reciprocity
• altruism

• In altruism, an individual reduces its own fitness to help other members of its social group.

• inclusive fitness
• kin selection

Eusocial behavior is an example of extreme altruism.

• Eusocial species live in large groups of mostly nonreproductive individuals.
• haplodiploid species: social insects (wasps, bees, ants)

• Queen

• Minor worker

• Major worker

• diploid species: termites, snapping shrimp, naked mole rats

• Eusocial behaviors likely evolve by kin selection.

• KEY CONCEPT Some animals other than humans exhibit behaviors requiring complex cognitive abilities.