* not completed

. What model of selection acting on male and female gamete size is most likely responsible for the evolution of anisogamy?

Stabilizing selection correct incorrect

Directional selection correct incorrect

Neutral evolution (no selection) correct incorrect

Disruptive selection correct incorrect

Artificial selection correct incorrect

* not completed

. Many organisms in the deep sea live in conditions where resources are rare and populations are small and sparse. Many of those species are also hermaphroditic. Which of these is a plausible explanation for high rates of hermaphroditic species there?

Reproductive assurance: any individual of the same species is a potential mate correct incorrect

Excess energy: excess resources can be allocated to the other sex function correct incorrect

Size advantage: males are more successful when large, but female fitness does not change with size correct incorrect

Small body size: one sex or the other needs only a miniscule body size for full function correct incorrect

Inbreeding: populations are inbred and hermaphroditism is a side effect correct incorrect

* not completed

. Mating fiddler crabs use several types of sexual selection. Males battle each other for territory using their greatly enlarged claws. The territories preferred by females are those in the most physiologically stressful area, and only healthy males can maintain them for long. The males also raise their claws to signal females; those that reach the greatest heights are most noticeable because females are attuned to look upwards for predators. Which model of sexual selection is least likely to impact this mating system?

Good genes mechanism correct incorrect

Direct benefits correct incorrect

Perceptual bias correct incorrect

Male-male competition correct incorrect

All of these models apply to the scenario equally well. correct incorrect

* not completed

. Many primates, but not humans, have penises with spines and testicles that are relatively large. What does this suggest about a major form of sexual selection in those primates?

These traits are both strategies for success in the face of sperm competition. correct incorrect

Penile spines are preferred by females because they are indicative of genetic quality. correct incorrect

Large testicles give males an advantage in male-male competition. correct incorrect

Females compete with each other for males, in a case of sex role reversal. correct incorrect

The spines ensure that males mate only with individuals of the same species. correct incorrect

* not completed

. What explains the concept that underlies Bateman's principle?

Females prefer the most beautiful males in some populations. correct incorrect

Larger males can defend territories of higher quality than smaller males. correct incorrect

Pleiotropy in sensory systems makes certain males more attractive to females. correct incorrect

Females that mate more frequently have a greater success of having mated with a male of high genetic quality. correct incorrect

Since eggs are energetically expensive, they tend to be the limiting resource in reproductive systems. correct incorrect

* not completed

. In promiscuous mammals, males often have greatly enlarged testicles compared to closely related monogamous species. What model of sexual selection best explains this observation?

Runaway sexual selection correct incorrect

Good genes model correct incorrect

Sperm competition correct incorrect

Perceptual biases correct incorrect

Male-male combat correct incorrect

* not completed

. Which trait is most likely a product of sexual selection by female choice?

Stronger antlers on an elk that improve an individual's chances in combat correct incorrect

Bright coloration on a fish that is indicative of genetic quality correct incorrect

Barbs on the penis that remove the sperm of rival males and increase probability of fertilization correct incorrect

Successful bedbugs with the ability to overcome the female's resistance to mating correct incorrect

Satellite male behavior by horseshoe crabs, in which an unmated male piggybacks onto a mating pair in the hopes of fertilizing at least a few eggs correct incorrect

* not completed

. Sexual selection in flowering plants is most closely analogous to what mode of sexual selection in animals?

Perceptual bias correct incorrect

Fisher's runaway process correct incorrect

Good genes mechanism correct incorrect

Sperm competition correct incorrect

Direct benefits model correct incorrect

* not completed

. Sea turtles have environmental sex determination: more males are born at low temperatures and more females at high temperatures. Presently, females bury their eggs at a depth in the sand where both sexes are produced at nearly equal frequencies. Which scenario would not be a realistic response of turtles to climate change and global warming?

Adoption of chromosomal sex determination in areas of increased temperature correct incorrect

Endangerment or extinction as turtles produce female skewed populations correct incorrect

Adaptation by nesting turtles to build nests of different depths, maintaining temperature profile and sex ratio correct incorrect

Migration of populations to cooler regions, maintaining temperature profile of nests and the sex ratio correct incorrect

Adaptation by turtle populations, in which the temperature threshold for producing female embryos shifts upward. correct incorrect

* not completed

. A female fig wasp arrives at a fig to lay her eggs. When they hatch, they will mate with other wasps inside the fig. She observes that several other females have already laid eggs here. Which strategy will maximize her fitness (number of descendants)?

Lay only female eggs correct incorrect

Lay only male eggs correct incorrect

Lay more male eggs than any of the previous females, and then as many female eggs as possible correct incorrect

Lay more female eggs than any of the previous females, and then as many male eggs as possible correct incorrect

Lay eggs at 50:50 sex ratio correct incorrect

* not completed

. Which of the following is not a hypothesized advantage of sexual reproduction?

It creates genetic variation. correct incorrect

It recombines different advantageous alleles and separates them from harmful ones. correct incorrect

It helps remove deleterious genes. correct incorrect

It increases resistance to parasites. correct incorrect

It reduces the chances of producing defective offspring. correct incorrect

* not completed

. What is the "twofold" cost of sexual reproduction?

Sexually reproducing species must produce male and female sex organs. correct incorrect

Sexually reproducing species must find and attract mates. correct incorrect

Sexually reproducing females must resist mating attempts and sperm entry. correct incorrect

Given equal fecundity, sexually reproducing females will produce only half the number of female offspring of asexually reproducing females. correct incorrect

Sexually reproducing species must find mates, and sexually selected traits reduce survival. correct incorrect

* not completed

. Which of these provides the selection pressure maintaining sexual reproduction, according to the Red Queen hypothesis?

Females are able to choose males with superior genes. correct incorrect

Sexual populations have only half the fitness of asexual populations. correct incorrect

Pathogens of the sexual organism evolve to overcome the organism's defenses. correct incorrect

Stabilizing selection maintains a 50:50 sex ratio. correct incorrect

Strains with different beneficial mutations are able to come together during recombination. correct incorrect

* not completed

. Two individuals in an asexual population have distinct, beneficial mutations. When their descendants compete with each other, one of those mutations is lost to extinctions. This phenomenon is called

selective interference. correct incorrect

clonal interference. correct incorrect

the twofold cost of males. correct incorrect

Bateman's principle. correct incorrect

Fisher's runaway. correct incorrect

* not completed

. In which population would you expect to observe individuals with the greatest inbreeding depression?

A population of fig wasps, where many matings are between full siblings correct incorrect

A sexual population of ants with a highly skewed sex ratio—many more females than males correct incorrect

A population of corals that reproduces by self-fertilization for the majority of offspring produced, but occasionally outcrosses sexually correct incorrect

A small population of whales, where many harmful mutations are fixed by genetic drift correct incorrect

An asexual population of lizards, where all reproduction is performed by self-fertilization correct incorrect