Ch. 9 Reproductive Strategies Ecology: The Economy of Nature 8th edition Flashcards Preview

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Flashcards in Ch. 9 Reproductive Strategies Ecology: The Economy of Nature 8th edition Deck (57)
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Which type of reproductive strategy reduces the chances of a parent passing on harmful mutations to their offspring?

sexual reproduction


Frequency-dependent selection is a phenomenon that occurs when natural selection favors a relatively _____ phenotype.



The most common mating system among animal taxa is _____.



Which statement is FALSE?

Extant asexually reproducing species are all relatively recently evolved from sexually reproducing ancestors.


Flowers with separate male and female sexes would be favored by selection in plants if _____.

the addition of a male function incurs a net cost for a female


Organisms that reproduce via parthenogenesis differ from organisms that reproduce via vegetative reproduction because they _____.

produce an embryo


In what way can extra-pair copulations increase the fitness of a female bird?

The female's offspring will be more likely to survive and reproduce in future environmental conditions because of the increased genetic variation among the offspring.


Each vegetatively reproducing individual belonging to coral species A produces 250 offspring during each reproductive event. Typically, in coral species B, whose individuals always reproduce sexually, a single individual will produce 500 offspring. However, a mutation has arisen in one particular species B female that causes her to contribute only half as many copies of her genes to her offspring as she normally would. How many offspring would this female have to produce to pass along the same number of her genes to the next generation as an individual of coral species A?

1,000 offspring


Over time, frequency-dependent selection tends to result in a _____ male to female sex ratio on average.



You are performing an experiment on runaway sexual selection in stalk-eyed flies. In the laboratory you supply individuals with plenty of food and exclude all predators to measure female preference for males. You give females the choice between males with short or long eyestalks, and you find that every time, females prefer males with the longest eyestalks. Further, while performing mating trials, you find that females who mate with males with longer eyestalks produce male offspring with longer eyestalks. However, after several generations you discover that the males' eyestalks are not getting longer. By taping additions onto male eyes, you determine that females still prefer males with longer stalks, yet the size of the male stalks does not continue to grow from generation to generation. What is the best explanation?

Males have reached the genetic limit for the production of long eyestalks.


With the majority of honeybees, after the queen mates with drones (male bees), she uses the sperm to fertilize eggs that become _____.

diploid workers, but she does not use the sperm to fertilize eggs that become haploid drones


In a species of beetle, females selectively abort their more energetically costly female offspring when resources are scarce. In fact, two units of resources are required to produce each male offspring, whereas six units of resources are required to produce each female offspring. While one of a female's goals is to produce the largest number of offspring possible with the resources available, evidence suggests that each female offspring produced earn a female four fitness points, while each male offspring produced earns the female just two fitness points. If there are 36 resource units available to a female for reproduction, what is the optimal number of female offspring for her to produce to get the most fitness points?



You are studying the mating system of a newly discovered rodent on an island in the South Pacific. You find a male and female in a burrow caring for their newborn young, and you decide to observe them for several weeks. You discover that as soon as the young are old enough to begin foraging for themselves, the female leaves the nest and seeks out a new partner; the male stays behind. The female makes a new burrow, mates with a new male, and rears her offspring with him until they are old enough to forage. Then she again leaves and seeks out a new male. What kind of mating system does this rodent species display?



The Red Queen hypothesis only occurs in organisms that reproduce ________.



Which parent will pass the largest total number of its genes onto its total offspring?

a diploid parent that produces 750 offspring via vegetative reproduction


The sex of a blue-headed wrasse is environmentally determined because _____.

a female becomes male when the dominant male dies


You are studying the mating system of water mites in a laboratory environment. You observe that the females fertilize their eggs by consuming randomly distributed spermatophores, small packets of sperm and nutrients that males stick to underwater substrates. The more spermatophores a female consumes, the more offspring she produces. You also find that males produce one of these spermatophores approximately every 2 hours and randomly stick them to underwater substrates as they swim around, whether a female is in the vicinity or not. Which type of mating system(s) are these observations most consistent with?



What would NOT be an effective strategy for a plant to minimize the fitness costs associated with self-fertilization?

physically separating male and female flowers on the same plant


In a tropical plant species, one individual female mates with a male and produces 1,000 offspring. Another individual exhibiting hermaphroditism is capable of reproducing sexually with males but also possesses male reproductive organs that allow it to reproduce sexually with females. If a hermaphroditic individual also produces 1,000 offspring, how many MORE total copies of each gene will the hermaphrodite pass on to its offspring than the female that is capable of reproducing only with males?



Which scenario is an example of a sexual conflict?

A new dominant male lion takes over a pride and kills the newborn cubs fathered by the previous dominant male lion.


What would you expect to find strong evidence for in a promiscuous animal species?

selection on primary sexual traits


How many cells will a single bacterial cell become after six rounds of binary fission, assuming no cells die?

64 cells


In partial meiosis in which a germ cell undergoes only the first part of meiosis, the resulting gametes are typically _____ and are _____ one another.

diploid; different from


You are mountain climbing when you stumble upon a fight between two adult rams. You notice that the winner possesses much larger horns than any of the other nearby males. You watch as the winner chases off the intruder and then mates with several females who follow him around. You also observe that if another male comes near one of the females or attempts to mate with one, the male chases them off immediately. This mating system is _____; the male engaging in _____ when he chases off other males; and large male horns represent _____ for a female.

polygyny; mate guarding; nonmaterial benefits


A diploid female that reproduces via parthenogenesis possesses germ cells that undergo complete meiosis. Choose the answer that explains how her gametes form a diploid embryo.

The haploid gametes fuse to form a diploid cell.


Most theoretical models concerning mechanisms of reproduction conclude ________ reproduction provides an advantage for adapting to temporal and spatial variation in the ________ environment.

sexual; biotic


How does the Red Queen hypothesis help us understand the fitness benefits of sexual reproduction?

Sexual reproduction produces genetic variation that allows some offspring to survive evolving parasites.


Identify the conditions that favor self‑fertilization over outcrossing in a hermaphroditic plant species.

high herbivory activity and small population size


Researchers have discovered that artificial selection pressure caused by human fishing activities can skew sex ratios in salmon populations. This is due to the fact that larger fish are preferentially harvested and male salmon are typically larger than female salmon. This means that males are inadvertently harvested more often than females.
Choose the other salmon traits that might evolve in response to intense fishing practices that selectively harvest larger adult fish.

faster development to maturity and reduced adult body size


Many bird species engage in social monogamy but copulate with multiple individuals. How have these extra‑pair copulations influenced the evolution of mate guarding in socially monogamous species?

Extra-pair copulation promotes mate guarding because the male partner of a monogamous pair does not benefit from rearing an unrelated chick.