Deck 5: Evolution and Sex

Question 1

Sexual monomorphism in body size is not a good predictor of mating systems because:

A) It occurs only in monogamously pair-bonded primates
B) It can occur in primates with diverse mating systems
C) It is never found in polygamous primates
D) It is characteristic of both polygamous and polygynous primates

Answer 1

B

Question 2

The variance in male reproductive success is equal to the variance in female reproductive success when:

A) Both sexes maintain exclusive monogamy
B) One male monopolizes reproductive access to multiple females
C) Multiple males share copulations
D) Two or more females mate with the same male

Answer 2

A

Question 3

The operational sex ratio (OSR) is the ratio of the number of:

A) Pregnant to nonreproductive females in a group
B) Ovulating females in a group at any one time
C) Male infants to the number of female infants born in each cohort
D) Reproductively active males to reproductively active females in a group

Answer 3

D

Question 4

The most extreme cases of sexual dimorphism in body size tend to be found in:

A) Pair-bonded societies
B) Polygynous societies
C) Polygamous societies
D) Polyandrous societies

Question 5

Males with the largest testes relative to body size are likely to:

A) Form monogamous pairbonds with females
B) Have semiterrestrial lifestyles
C) Be the sole breeding male in their social groups
D) Live in multi-male groups

Question 6

Which of the following is not likely to be a male option when females avoid one another?

A) Joining a female and helping to defend a mutual territory
B) Attempting to monopolize more than one female in discrete core areas
C) Cooperating with related males to defend a community of females
D) Joining other males until a female selects him as a mate

Question 7

Extra-group copulations:

A) Have been observed or are known to occur in most primate species
B) Occur in all primates except those such as gibbons, which form pairbonds
C) Are reproductive strategies employed by males, but not females
D) Are strong indicators of paternity certainty

Question 8

Turn-over in male membership in female groups:

A) Can increase the variance in male reproductive success
B) Can reduce the variance in male reproductive success
C) Precludes males from ever forming multi-male groups
D) Is timed so that infants sired by one male can be weaned

Question 9

Which of the following is not a potential benefit of female strategies that involve mating with multiple partners:

A) Confusing paternity
B) Reducing the risks of male aggression
C) Ensuring fertilization
D) Avoiding predators

Question 10

Mate guarding:

A) Increases a male's access to an ovulating female
B) Is how males prevent other females from joining their groups
C) Reduces a male's confidence of paternity
D) Prevents females from defending their food

Question 11

Female proceptivity:

A) Is restricted to their ovulatory cycles
B) Is a way to attract male sexual interest
C) Is only observed in species with sex skins
D) Is limited to seasonal breeders

Question 12

Heterosexual "friendships" among baboons and macaques:

A) Never involve recent male immigrants
B) Lead to sexual fidelity between partners
C) Exclude all but the most dominant males
D) Are ways for subordinate males to increase their mating success

Question 13

Evolutionary theory predicts that females should be most discriminating in their choice of mates:

A) At times in their cycles when the probability of conception is high
B) At times in their cycles when the probability of conception is low
C) At times when food resources are most abundant
D) In single-male groups, where their mate choices are most limited

Question 14

Which of the following males is most likely to protect an infant?

A) A male Hanuman langur who has just taken over a new troop
B) A male gibbon with a long-term pairbond with the infant's mother
C) A transient male orangutan passing through a female's core area
D) A male chimpanzee that encounters a female who has just immigrated
Into his community with her infant

Question 15

The similarities in the fluid, fission-fusion grouping patterns of spider monkeys and chimpanzees are most likely explained by:

A) Their close phylogenetic relationships
B) Their multi-male, male-female societies
C) The operational sex ratios in their groups
D) The ecological conditions that favor avoidance of intragroup feeding
Competition

Question 16

A male's reproductive success is measured by:

A) The number of different partners he mates with
B) The number of sexually receptive females he mates with
C) The number of female friendships he can maintain
D) The number of surviving offspring he sires

Question 17

Male dominance hierarchies:

A) Predict a male's lifetime reproductive success
B) Correlate imperfectly with male reproductive success
C) Correspond with levels of sperm competition
D) Occur only among aseasonal breeders

Question 18

Polyandrous mating systems are those in which:

A) One female mates with two or more males
B) One male mates with two or more females
C) Both sexes mate exclusively with a single partner
D) Both sexes mate with multiple partners

Question 19

List three traits that might make particular male primates more attractive to females as mates.

Question 20

Discuss the possible costs and benefits of concealed ovulation versus the visible advertisement of ovulation through sex skins from both the female and male perspective.

Question 21

In many human cultures, men are more likely to divorce wives who commit infidelities than women are to divorce their husbands for the same offense. Using your knowledge of evolutionary biology, provide an explanation for this tendency and discuss the conditions under which you might expect men and women to react similarly to a spouse's infidelity.

Question 22

Describe the ways in which levels of sexual dimorphism (including sexual monomorphism) can affect male-female and female-female relationships.

Question 23

Draw the graph that depicts the polygyny threshold, being sure to label both axes. In two or three sentences, describe what evolutionary principle(s) it depicts.

Question 24

Explain the distinctions between graded signals and honest advertisements as they apply to sexual swellings.

Question 25

What is the female dilemma, and what are some of the strategies female primates employ to overcome it?

Question 26

Discuss how mating patterns affect the genetic composition of primate populations, and therefore influence the viability of populations.

Question 27

Female gibbons are found in both single- and multi-male groups. Describe the conditions that favor single versus multi-male groups, and consider the costs and benefits to the female as well as the males in both types of groups.