49. Animal Behavior

A behavior is considered adaptive if it increases an individual's fitness. How is fitness measured? Select True or False for each statement.

T/F Strength

T/F Body size

T/F Speed

T/F Number of viable offspring

A region of the canary forebrain shrinks during the nonbreeding season and enlarges when breeding season begins. This change is probably associated with the annual

a. Addition of new syllables to a canary's song repertoire

b. Crystallization of subsong into adult songs

c. Sensitive period in which canary parents imprint on new offspring

d. Elimination of the memorized template for songs sung the previous year

A male redwing blackbird will chase predatory birds away from his breeding territory during nesting season. Which hypothesis best explains his behavior?

a. He is acting for the good of the species. He may die, but other birds of his species will be saved.

b. He knows this will increase his fitness, so he chases away the predator.

c. He carries a gene that causes fathers to protect their offspring, which increases inclusive fitness.

d. He has imprinted on the offspring in his nest, so he knows that they are his.

Why does altruism seem paradoxical?

a. Sometimes altruistic behavior is actually selfish.

b. Altruism does not actually help others.

c. Alleles that cause an organism to behave altruistically should be selected against since these alleles should lower the organism's fitness.

d. Animals behave altruistically to help the species, but sometimes their behavior harms the species.

Although many chimpanzees live in environments with oil palm nuts, members of only a few populations use stones to crack open the nuts. The likely explanation is that

a. The behavioral difference is caused by genetic differences between populations.

b. Members of different populations have different nutritional requirements.

c. The cultural tradition of using stones to crack nuts has arisen in only some populations.

d. Members of different populations differ in learning ability.

Some airports have attempted to scare geese off by playing goose alarm calls over loudspeakers. This tactic kept the geese away initially, but soon the geese ignored the alarm calls. How would you explain this outcome?

a. The alarm calls are a social signal that geese ignore unless they can see the other geese.

b. The geese became imprinted on the alarm calls.

c. The geese used spatial learning to navigate the environment of the airport.

d. The geese became habituated to the alarm calls when no danger was present.

Is it true that all organisms forage optimally? Why or why not?

Which of the following is not required for a behavioral trait to evolve by natural selection?

a. In each individual, the form of the behavior is determined entirely by genes.

b. The behavior varies among individuals.

c. An individual's reproductive success depends in part on how the behavior is performed.

d. Some component of the behavior is genetically inherited.

The male cuttlefish in the chapter-opening photo can rapidly change their skin colors (under nerve control) to flash warning patterns to rivals. Predict the proximate and ultimate causes of this behavior.

Propose an evolutionary hypothesis to explain the observation that some bird populations do not migrate if people supply food for them in feeders.

A chorus of frogs fills the air on a spring evening. The frog calls are courtship signals.

What are the functions of courtship behaviors?

How might a behavioral ecologist explain the proximate cause of this behavior?

The ultimate cause?

Hamilton's rule states that an altruistic allele could spread in a population if Br > C, where B represents the fitness benefit to the recipient, r is the coefficient of relatedness between altruist and recipient, and C represents the fitness cost to the altruist. If r = 0.5 between the altruist and the recipient, what would the ratio of costs to benefits have to be for the altruistic allele to spread?

a. C/ B > 0.5

b. C/ B > 0

c. C/ B < 0.5

d. C/ B < 0

Crows break the shells of certain molluscs before eating them by dropping them onto rocks. Hypothesizing that crows drop the molluscs from a height that gives the most food for the least effort (optimal foraging), a researcher dropped shells from different heights and counted the drops it took to break them. a. The researcher measured the average drop height for crows and found that it was 5.23 m. Does this support the researcher's hypothesis? Explain. b. Describe an experiment to determine whether dropping molluscs from an optimal height is learned or innate.