Chapter 12 Quiz

. Which of the following is a case of altruism?

A plant releases allelopathic chemicals, harming its competitors and itself.

A shrimp digs a burrow that it shares with a goby that keeps watch for predators.

A prairie dog gives up a foraging opportunity to keep watch for predators.

Individuals in a flock of birds are less susceptible to predators than individuals alone.

A baby bird aggressively begs, resulting in less food available to its siblings.

. Individual amoebae of the slime mold Dictyostelium discoideum aggregate to form a spore-producing fruiting body. Cheaters make spores, but do not contribute to the stalk. Since many more spores with cheating genotypes are dispersed, they have higher fitness. Why does directional selection not lead to fixation of the cheater genotype?

This is actually a case of frequency-dependent selection. With too many cheaters in a population, the fruiting body's stalk is not built well, and all individuals have lower fitness.

Noncheating genotypes are maintained for the harmony and balance of nature.

Individual amoebae compete against groups of multicellular predators; the noncheating genotype is favored during this competition.

Individual amoebae form "slugs" only with other amoebae that have the same genotypes.

Reproductive success is independent of whether an organism exists as a single cell or as part of a multicellular "slug."

. Which statement is the least likely explanation for the evolution of behaviors in which subordinate male animals assist dominant males defending mating territories or in mating displays?

Dominant males occasionally allow subordinate males to mate with females.

Subordinate males succeed dominant males, inheriting their territory, when they die.

The subordinate males mistake the dominant males for females.

Subordinate males are related to dominant males and benefit indirectly by inclusive fitness.

Subordinate males occasionally have successful "sneak" copulations with females.

. In which situation would you expect the interacting parties not to cooperate?

The individuals are closely related.

The individuals have a history of repeated social interactions.

An individual that provides assistance in the present will in turn be assisted in the future.

Individuals are unlikely to encounter each other again in the future.

Individuals are part of a social group in which noncooperating individuals are punished.

. If a new mutant strategy appears in a population that has adopted an evolutionarily stable strategy (ESS), which of the following will result?

Natural selection will maintain the mutant strategy because the variation in strategy may be useful in future environments.

The mutant strategy will not be able to increase in numbers in the population under the influence of natural selection.

The evolutionarily stable strategy will be displaced because of natural selection in favor of the mutant strategy.

The members of the population using the original strategy will act with aggression toward those exhibiting the mutant strategy.

Antagonistic pleiotropy will allow an equilibrium in which both strategies are maintained in the population.

. Suppose five boats are adrift at sea, each one containing a number of your relatives, and you have the power to save one boat from a dire fate. According to kin selection theory, it would be in the best interest of your genome to save a boat that contains

two of your brothers.

seven of your cousins.

both of your parents.

one sister, one half-brother, and three cousins.

four half-siblings.

. A woman has a son with her first partner, and that son has a son of his own—the grandchild of the original woman. The original woman also has a son with a second partner, who also grows up to have another son; a second grandchild. What is the relatedness, r, of the two grandchildren?

0.0625

0.125

0.25

0.875

2

. Which of these is a "spiteful action"?

A small child steals food from their baby sibling.

Children socially ostracize a classmate for no apparent reason.

A student turns in a classmate for cheating and as evidence admits to having cheated himself.

A weaker student befriends a bully for protection.

A student at a track meet intentionally trips one of her competitors.

. In birds and mammals, parental care tends to be provided by females, while in fishes and frogs, it tends to be provided by males. Which statement about this difference is consistent with evolutionary theory?

Polygynous species tend to have high levels of paternal care.

Both of these strategies are suboptimal, as there is never any situation in which a parent benefits from avoiding parental care.

Selection favors defection more strongly in the sex for which parental care is more costly.

If one sex provides parental care, it is always the heterogametic sex.

If one sex provides parental care, it is always the individual that makes a greater energetic investment into the gametes.

. Upheaval in the social groups of lemurs is accompanied by an increase in infant mortality because

the infants are direct targets of tribal warfare.

many lemurs are unable to distinguish their own offspring from those of others.

most infant deaths are due to siblicide.

infanticide is required for a social group's expansion to new habitat.

immigrant males maximize their own fitness by killing infants.

. Pre-eclampsia is a pregnancy complication that is often explained as resulting from parent-offspring conflict. What underlies this conflict?

The mother wants to provide the fetus with plenty of resources.

The fetus demands more resources from the mother than would be optimal for her.

The fetus rejects excess resources to assist its siblings.

Single pregnancies are much more common than multiple pregnancies (i.e., twins).

Women gain more fitness (number of descendants) from earlier pregnancies than from later ones.

. Eusociality occurs in multiple species of insects. What is the characteristic of wasps, bees, and ants that facilitates the presence of sterile workers?

Diapause (a period of suspended development)

Haplodiploidy

Polyandry

Promiscuous mating

High mutation rates

. Why are killer genes, like the t locus that causes segregation distortion in mice, inherited in tightly linked units with resistance alleles?

Linkage insures that successful mating will occur only with members of the same species; outbreeding would lead to low numbers of viable gametes.

Correct positioning of the two alleles on a chromosome ensures that they will be incorporated into the product of meiosis that is most likely to become a gamete.

If the killer allele and the resistance allele were broken up by recombination, there would be no advantage to gametes carrying the killer allele.

Without the correct resistance allele, the killer allele will be functionless.

Killer genes make copies of themselves and insert themselves into new positions of the genome; resistance alleles linked to them ensure that they "resist" being removed by error correction enzymes.

. Cytoplasmic male sterility (CMS) arises out of conflict between _______ and _______.

the Golgi; the endoplasmic reticulum

X chromosomes; Y chromosomes

mitochondria; nuclear genes

mitochondria; the Golgi

ribosomes; chloroplasts

. Which of the following is most likely to favor the evolution of highly virulent parasites?

Transmission between unrelated members of the population

Transmission from parent to offspring

Multilevel selection (both within and among populations, occupying different hosts)

Strong effects on a subset of a population with a specific susceptible genotype

Mutualism between hosts and parasites

Chapter 12 Quiz

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