Question 1

The Emlen and Oring model of the evolution of social mating systems is based on sexual conflict theory, which assumes which of the following?

Accepted Answer

The Emlen and Oring model is based on the idea that females typically invest more energy into offspring than males, leading to sexual conflict and influencing mating systems.

Question 2

In elephant seals, a male competes with other males while defending several females with whom he mates. What term best describes this social mating system?

Accepted Answer

Female defense polygyny is the term that best describes the social mating system where a male competes with other males to defend several females with whom he mates. This system is characterized by males guarding females to ensure exclusive mating rights with them.

Question 3

In some hummingbirds, males compete for display sites on a lek. Females then visit the lek to select a mate. What term do Emlen and Oring use to refer to such a mating system?

Accepted Answer

Male dominance polygyny is the term used by Emlen and Oring to describe a mating system where males compete for territories or display sites that attract females for mating purposes, as seen in the lekking behavior of some hummingbirds.

Question 4

What method did Leisler use to test the Emlen and Oring model of the evolution of mating systems in birds?

Accepted Answer

Leisler used the comparative method to test the Emlen and Oring model, which involves comparing different species to understand the evolution of mating systems in birds.

Question 5

What association did Leisler find between mating system and habitat quality in the birds he studied?

Accepted Answer

Leisler found that monogamy was prevalent in poor-quality habitats, as it often requires both parents to invest heavily in offspring survival, which is crucial in challenging environments.

Question 6

Social monogamy is rare in mammals but common in birds. What difference is hypothesized to explain this observation?

Accepted Answer

The need for biparental care is hypothesized to explain why social monogamy is rare in mammals but common in birds. In many bird species, the survival of offspring is significantly enhanced by the care and provisioning of both parents, making social monogamy a more advantageous mating system.

Question 7

What study design was used by researchers to study mating systems in California mice and poison frogs?

Accepted Answer

The answer of What study design was used by researchers...

Question 8

Which hypothesis can explain social monogamy in species without biparental care?

Accepted Answer

Territorial cooperation can explain social monogamy in species without biparental care, as it suggests that pairs may form to defend a territory more effectively, providing mutual benefits in terms of resource access and protection.

Question 9

You discover a new species of bird and observe that males defend similar-sized territories early in the breeding season and that females then settle on these territories. On some male territories, only one female settles to breed, while on others, multiple females settle and breed. How would you best classify this social mating system?

Accepted Answer

Polygyny is the correct classification for this social mating system because it involves one male mating with multiple females who settle and breed on his territory.

Question 10

In the polygyny threshold model, why do some females mate polygynously when they have the opportunity to mate monogamously?

Accepted Answer

The polygyny threshold model suggests that females may choose to mate polygynously if the benefits, such as access to more resources provided by a male with already mated females, outweigh the costs of sharing a mate and receiving less attention. This decision is often influenced by the quality of the territory or resources the male controls.

Question 11

What evidence suggests that carrion beetles exhibit resource defense polygyny?

Accepted Answer

In resource defense polygyny, a dominant male controls a valuable resource, such as a carcass, and mates with multiple females attracted to that resource.

Question 12

Which of the following is a necessary aspect of the hotspot hypothesis?

Accepted Answer

The hotspot hypothesis suggests that males aggregate in areas where the activity of females is high, as these locations increase their chances of encountering potential mates. This is a necessary aspect of the hypothesis, focusing on the strategic positioning of males to maximize mating opportunities.

Question 13

You collect data at a lek and notice that a single male obtains over 70% of the matings that occur there. When he is experimentally removed, the remaining males move to different locations on the lek. What hypothesis best explains this observation?

Accepted Answer

The Hotshot hypothesis suggests that certain males (hotshots) are more attractive to females, and other males gather around them to increase their own chances of mating. When the hotshot is removed, the remaining males disperse, supporting this hypothesis.

Question 14

Which of the following is NOT true about sex-role reversed species?

Accepted Answer

In sex-role reversed species, it is still the females who produce larger gametes (eggs), while males produce smaller gametes (sperm). This aspect of gamete size does not reverse even in species where other traditional sex roles, such as parental care and mating competition, are reversed.

Question 15

Which of the following is characteristic of a promiscuous mating system?

Accepted Answer

In a promiscuous mating system, both males and females have multiple sexual partners, without forming exclusive pair bonds.

Question 16

Extra-pair copulations do NOT occur in which mating system?

Accepted Answer

The answer of Extra-pair copulations do NOT occur in which...

Question 17

Which of the following is NOT a proposed benefit of multi-male mating by females?

Accepted Answer

Reduced predation risk is not typically considered a benefit of multi-male mating by females. The other options are recognized benefits, such as reducing infanticide, increasing genetic diversity and quality, and potentially gaining additional parental care.

Question 18

Common crossbills (Loxia curvirostra) are a socially and genetically monogamous bird whereas Gunnison's sage-grouse (Centrocercus minimus) form leks and are polygynous. What prediction can you make about the degree of variation in male mating success in these two species?

Accepted Answer

The answer of Common crossbills (Loxia curvirostra) are a socially...

Question 19

What feature distinguishes promiscuity from polygynandry (plural breeding). Describe one species that exhibits each breeding system.

Accepted Answer

The answer of What feature distinguishes promiscuity from polygynandry (plural...

Question 20

What two factors favor the evolution of monogamy?

Accepted Answer

The answer of What two factors favor the evolution of...

Quiz 13: Mating Systems