Deck 4: Evolution and Social Behavior

Question 1

Which of the following is not a source of genetic variation?

A) Mutations
B) Sexual reproduction
C) Recombination
D) Genetic drift

Answer 1

D

Question 2

Neutral mutations:

A) Are under strong directional selection pressures
B) Are invisible to natural selection
C) Can never confer benefits to their carriers under any conditions in the future
D) Arise from close inbreeding

Answer 2

B

Question 3

Inbreeding is an example of:

A) Extreme positive assortative mating
B) Random mating
C) Extreme negative assortative mating
D) Mate choice for MHC genes that differ from one's own

Answer 3

A

Question 4

Small, isolated populations are vulnerable to extinction because:

A) Genetic drift and gene flow will increase within population genetic variation
B) Genetic drift will reduce genetic variation within the population
C) Gene flow will reduce genetic variation within the population
D) Genetic drift will increase genetic variation within the population

Question 5

One of the main problems with using group selection arguments to explain the evolution of altruism is that:

A) We now know that kin selection explains all altruistic behavior
B) "Cheaters" would be quickly eliminated by natural selection
C) Altruism requires opportunities for reciprocity, which few primates have
D) Selfish individuals should be able to outcompete altruists

Question 6

Which of the following is not an assumption of kin selection theory?

A) Altruistic behavior that benefits relatives diminishes the altruist's inclusive fitness
B) Kin must have opportunities for repeated interactions
C) Behavior has at least a partial heritable component
D) Relatives share some of their genes by common descent

Question 7

All else being equal, which of the following pairs is most likely to help one another?

A) Full cousins
B) Aunt-niece
C) Half siblings
D) Full siblings

Question 8

Kurland's study of Japanese macaques demonstrated that close relatives had higher rates of interaction than distant kin and non-relatives because:

A) Close relatives were less likely to groom one another
B) Close relatives do not share genes
C) Close relatives spent a greater proportion of their time in proximity
D) Close relatives were less likely to respond to one another's distress calls

Question 9

Which of the following is not a possible explanation for the deaths of infants that sometimes follow male take-over events of Hanuman langur groups?

A) Selection favors males who kill their own sons to prevent competition with them
B) Take-overs involve highly aggressive behaviors
C) Lactating females will cease lactating and resume ovulating sooner
D) Males have much to gain, and little to lose, by killing infants sired by their competitors

Question 10

The coalitions between two male chimpanzees against a third male in Frans de Waal's classic study of Chimpanzee Politics:

A) Provide strong evidence of kin selection
B) Could have been mutually beneficial to both males
C) Are responses to captivity, as no wild primates behave this way
D) Reflect stable, life-long bonds

Question 11

Seyfarth and Cheney demonstrated that vervet monkeys respond to distress calls from:

A) Close kin only; they never respond to nonkin
B) All kin independent of degree of relatedness
C) Kin and nonkin grooming partners
D) Kin and high ranking nonkin

Question 12

Affiliative relationships among male primates are expected when:

A) Dispersal patterns are male-biased
B) Males are philopatric
C) They live in matrilocal societies
D) Both sexes disperse from their natal groups

Question 13

According to evolutionary theory, true altruistic behavior:

A) Benefits the fitness of both actor and recipient.
B) Benefits the fitness of the actor at a cost to the fitness of the recipient.
C) Costs the fitness of the actor at a benefit to the recipient.
D) Costs the fitness of both actor and recipient.

Question 14

The Prisoner's dilemma illustrates:

A) The importance of kin selection in behavioral evolution
B) The conditions that are necessary for cooperation to evolve
C) The trade-offs between fast and slow life histories
D) The female problem of balancing mate choice and confusing paternity

Question 15

Female marmosets that remain in their natal groups and help their mothers to carry new infants instead of dispersing and reproducing themselves:

A) Make no evolutionary sense
B) Are behaving altruistically
C) May be benefiting their inclusive fitness
D) Improve their reproductive success

Question 16

Stabilizing selection:

A) Moves the population mean of a trait in the direction of the most fit variety
B) Reduces variability in the population by selecting against less fit phenotypes
C) Selects for different phenotypes within a population
D) Emphasizes intrasexual competition instead of intersexual competition.

Question 17

Discuss at least three difficulties with determining when behaviors are adaptive.

Question 18

What is the equation for Hamilton's rule? Explain what each of the variables refers to, and describe what the equation predicts about when an individual should help his or her kin.

Question 19

Two females in a muriqui group have each given birth to 6 offspring. One of these "mega-moms," BS, has given birth to 5 daughters and one son. Her oldest daughter, BR, has a daughter of her own. The other mega-mom, NY, has given birth to 2 daughters and 4 sons. Using this information, answer the following questions:
A. Which individuals represent BS' inclusive fitness?
B. What is the difference between BS' and NY's inclusive fitness to date?
C. What would be the difference between BS' and NY's current inclusive fitness if two of NY's sons had fathered one offspring each?

Question 20

Mantled howler monkey troops can consist of both unrelated females and unrelated males because both sexes disperse from their natal groups. Describe the kind of evidence that would be needed to support an argument that group selection occurs in these primates.

Question 21

The risks of extinction are greater in small, isolated populations of primates (and other organisms) than in large, continuous population. Provide two reasons why this is the case.

Question 22

During your field study of wild Japanese macaques, you observe a fight between two females [A and B] at a food source. A third female [C] runs to the assistance of female A, and joins her in threatening female B. Using your knowledge of evolutionary theory, briefly explain the conditions that could account for female C's behavior under Kin Selection, Reciprocal Altruism, and Mutualism. Be sure to consider the fitness costs and benefits to both actor (female C) and recipient (female B), and any other necessary conditions that might apply in your answers.

Question 23

There are many possible reasons why the behavior we observe in nonhuman primates appears to be inconsistent with our predictions based on evolutionary theory. One reason may be that our theories about behavioral evolution are wrong, or need to be further refined. Another reason may be that the conditions under which we are observing the behaviors differ from those under which the behaviors evolved. Select a primate and briefly discuss how captive conditions are known, or might be predicted to affect any aspect of that species' social behavior compared to wild conspecifics.