Question 1

The evolution of physical traits of males to attract females or to compete with other males to mate with females is known as

Accepted Answer

Sexual selection is the process by which physical traits evolve in males to attract females or to compete with other males for mating opportunities. This competition can lead to the evolution of sexual dimorphism, or the physical differences between males and females of the same species. Sexual polymorphism refers to the existence of multiple different physical forms within a single sex, which is not directly related to sexual selection. Mate guarding, on the other hand, refers to the behavior of males to prevent their mate from copulating with other males after mating has occurred, and is not directly related to the evolution of physical traits.

Question 2

Which organisms are most likely to form monogamous relationships?

Accepted Answer

While monogamy can be found in various groups of organisms, including mammals and reptiles, it is most common in birds. This is because birds often form pair bonds to raise their offspring together.

Question 3

Which is TRUE about monogamy?

Accepted Answer

Monogamous relationships are favored when males provide significant parental care to offspring. This is because if males invest a lot of time and energy in caring for offspring, it becomes advantageous for them to mate with only one female and ensure that their efforts are not wasted on offspring that are not genetically related to them. In insects, such as bees and wasps, males provide significant parental care to offspring, which is why they often form monogamous relationships.

Question 4

In ring-necked pheasants (Phasianus colchicus), long spurs on the lower legs of males are genetically linked to a gene that influences the bird's susceptibility to disease (birds with longer spurs have histocompatibility complex genes that are linked to longer life spans). This is called

Accepted Answer

CAn honest signal is a trait that provides accurate information about an individual's fitness or quality, such as the long spurs in ring-necked pheasants indicating better health and longer lifespan. The handicap principle suggests that only the fittest individuals can afford to bear the cost of such traits, making them reliable signals of quality.

Question 5

Infanticide by a new dominant male lion confers which primary benefit to the dominant male?

Accepted Answer

Infanticide by a new dominant male lion results in the death of unrelated cubs, which allows female lions to become fertile again sooner. This benefits the dominant male because he can then mate with the females and pass on his genes, ensuring his genetic success. The other benefits listed in the other choices are also potential reasons for infanticide, but the primary benefit is the promotion of the dominant male's genetic success.

Question 6

Which is NOT a benefit of extra-pair copulation?

Accepted Answer

Extra-pair copulation does not increase the fitness of monogamous males by reducing energy expended on reproduction. In fact, males often invest significant energy in searching for and defending extra-pair mating opportunities. The benefits of extra-pair copulation typically accrue to the extra male and the offspring resulting from the extra-pair union, rather than to the monogamous pair.

Question 7

The male golden orb-weaving spider (Nephila clavipes) dies while still joined with the female following copulation. This is an example of

Accepted Answer

The male golden orb-weaving spider's death after copulation is an example of mate guarding. After copulation, the male spider remains attached to the female, preventing other males from copulating with her and ensuring that his own genes are passed on to any offspring. However, this attachment ultimately leads to the male's death.

Question 8

Which of the following is a primary sexual characteristic?

Accepted Answer

Primary sexual characteristics are those that directly involve the reproductive system, such as the presence of testicles in males. Manes in male lions and antlers in male elk are examples of secondary sexual characteristics, which are physical traits that enhance mating success but do not directly involve reproduction. Male birds having more colorful feathers than females are also an example of a secondary sexual characteristic.

Question 9

Mate guarding is selected for as a result of extra-pair copulation in

Accepted Answer

Mate guarding is selected for as a result of extra-pair copulation in monogamy because in a monogamous system, an individual invests more heavily in their partner and offspring, making it more advantageous to guard their mate and prevent extra-pair copulation in order to maximize their own fitness. In polygynous and polyandrous systems, where individuals mate with multiple partners, mate guarding may be less advantageous as an individual's fitness may not be as tied to a specific mate. In polygamous systems, an individual may also prioritize mate acquisition over mate guarding.

Question 10

Scientists have found that offspring of male tree frogs with long calls spend more time feeding and grow faster than offspring of male tree frogs with short calls. This supports the

Accepted Answer

The good genes hypothesis proposes that female preference for certain traits in males, such as a long call in tree frogs, indicates genetic quality and those offspring will inherit those desirable traits. Therefore, the offspring of male tree frogs with long calls growing faster supports the good genes hypothesis.

Question 11

What is the idea that a female selects the mate with a superior genotype called?

Accepted Answer

The idea that a female selects the mate with a superior genotype is called the good genes hypothesis. This hypothesis suggests that certain traits that indicate good genetic quality are preferred by females, and those desirable genes are passed on to the offspring. Other answer choices are incorrect or incomplete explanations of different concepts in sexual selection.

Question 12

Sexual traits that are disadvantageous to male survival may be attractive to a female because they suggest the male possesses a superior genotype to counteract the disadvantageous trait. This is known as

Accepted Answer

The handicap principle suggests that a disadvantageous trait can be attractive because it indicates that the male has a superior genotype that allows him to survive despite the handicap.

Question 13

According to the handicap principle, if an honest signal, the perceived advantage linked to the disadvantageous trait is

Accepted Answer

The handicap principle suggests that the disadvantageous trait, which is costly to maintain, signals genetic fitness. This trait is inherited by offspring, indicating that they too may possess the genetic quality that allows them to bear the cost of the trait.

Question 14

Traits such as the large, colorful tail feathers of male peacocks are known as _____ because they are related to _____.

Accepted Answer

Traits such as the large, colorful tail feathers of male peacocks are examples of secondary sexual characteristics because they are not directly related to fertilization, but rather play a role in courtship and attracting mates.

Question 15

Which of the following is a secondary sexual characteristic?

Accepted Answer

Tusks of male elephants are a secondary sexual characteristic because they are a physical trait that is present in one sex but not the other and is not directly involved in reproduction.

Question 16

When compared to asexual reproduction, costs of sexual reproduction potentially include all of the following EXCEPT

Accepted Answer

Sexual reproduction actually reduces the number of genes passed on to offspring, as it involves the recombination and shuffling of genetic material from two parents. The other options listed all represent potential costs of sexual reproduction.

Question 17

Which partner in a monogamous relationship might participate in extra-pair copulation?

Accepted Answer

In monogamous relationships, both paired males and paired females might participate in extra-pair copulation, as it is a behavior observed in both genders across various species, including humans.

Question 18

A peacock is significantly more colorful than a peahen and has a much larger tail. These traits allow the peacock to attract a mate but also make the peacock more visible to predators. This is an example of

Accepted Answer

The traits of being colorful and having a large tail in peacocks are a classic example of runaway sexual selection, where traits that confer no survival advantage can become exaggerated purely through mate choice. This can happen because the preference for the trait becomes linked to the trait itself, leading to a positive feedback loop where individuals with even more extreme versions of the trait are preferred.

Question 19

Which of the following traits would NOT be considered a material benefit?

Accepted Answer

Long tail feathers are a physical characteristic and do not provide any direct material benefit to the individual's survival or reproductive success. The other choices all provide direct material benefits that can increase an individual's chances of survival and reproductive success.

Question 20

Why has the microbe Wolbachia evolved mechanisms to alter the sex ratio of fruit flies and mosquitos?

Accepted Answer

Wolbachia are passed only through infected eggs, so by altering the ratio of male to female offspring, it ensures its transmission to the next generation through infected females.

Quiz 9: Reproductive Strategies