PCB 3043 Chapter 9

Suppose a pride of lions produces 20 cubs in one year. The population is composed of eight females and two males. On average, how many cubs does each male pass his genes to? -2.5 -10 -2 -20

-10

Select the definition of frequency-dependent selection. -A type of selection that confers a fitness advantage on the rarer phenotype in a population. -Selection of an advantageous phenotype such that its frequency becomes more common in a population. -A measure of how many offspring an individual passes its genes to. - type of selection which allows individuals with the more frequent phenotype to pass their genes to more offspring.

-A type of selection that confers a fitness advantage on the rarer phenotype in a population.

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 female partner of a monogamous pair does not benefit from rearing chicks from multiple males. -Extra-pair copulation selects against mate guarding because a single female cannot produce as many offspring with a single male as she can with multiple partners. -Extra-pair copulation selects against mate guarding because both partners of a monogamous pair benefit when they mate with multiple individuals. -Extra-pair copulation promotes mate guarding because the male partner of a monogamous pair does not benefit from rearing an unrelated chick.

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

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. -Stronger pathogen resistance. -Faster development to maturity. -Reduced adult body size. -Darker body color patterns.

-Faster development to maturity. -Reduced adult body size.

American black vulture females produce an average of two eggs per year. Suppose there is a population that contains five females and six males. Assume that a male can mate with more than one female. On average, how many gene copies will the females and males pass on to the chicks in a single year? -Females 2, Males 1.7 -Females 5, Males 6 -Females 1.7, Males -Females 4, Males 3.3

-Females 2, Males 1.7

American black vulture females produce an average of two eggs per year. Suppose there is a population that contains five females and four males. Assume that a male can mate with more than one female. On average, how many gene copies will the females and males pass on to the chicks in a single year? -Females 5, Males 5 -Females 2.5, Males 2 -Females 5, Males 4 -Females 2, Males 2.5

-Females 2, Males 2.5

Some species of freshwater snails can reproduce both sexually and asexually, but asexual reproduction yields more offspring. Identify the condition that favors sexual reproduction. -Small population size. -Heavily skewed sex ratio. -High parasite abundance. -Abundant food supply.

-High parasite abundance.

When females choose mates, why might extreme secondary sexual traits in males be good predictors of mate quality? -Only healthy males display secondary sexual traits, so males with the traits may have genes that keep them healthy. -Males with the most extreme traits tend to be monogamous and help raise their offspring, increasing offspring survival. -Males that survive despite the handicap of an extreme trait may signal that they are healthy and have good genes. -Those males with extreme traits are more aggressive and will defend their territories and their offspring from predators.

-Males that survive despite the handicap of an extreme trait may signal that they are healthy and have good genes.

Which of the following is a major difference between monoecious and dioecious plants? -Monoecious plants have imperfect flowers, and dioecious plants have perfect flowers. -Monoecious plants have male and female flowers on the same plant, and dioecious plants have either male or female flowers on a single plant. -Monoecious plants are incapable of self-fertilization, and dioecious plants are capable of self-fertilization. -Monoecious plants have either male or female flowers on a single plant, and dioecious plants have male and female flowers on the same plant.

-Monoecious plants have male and female flowers on the same plant, and dioecious plants have either male or female flowers on a single plant.

For most species of turtles, embryos that incubate at lower temperatures typically produce males, whereas those that incubate at higher temperatures produce females. Higher temperatures from global climate change could lead to skewed sex ratios among offspring and a reduction in breeding success as males become fewer in number. What behaviors during the egg-laying season might lead to potential behavioral adaptations that could help maintain an even sex ratio? -Sea turtles laying eggs in a communal nest with other sea turtles. -Sea turtles that nest during the cooler part of egg-laying season. -Pond turtles that have multiple clutches throughout egg-laying season. -Pond turtles that nest in more shaded areas around their ponds.

-Sea turtles that nest during the cooler part of egg-laying season. -Pond turtles that have multiple clutches throughout egg-laying season. -Pond turtles that nest in more shaded areas around their ponds.

What adaptations have evolved in plants that would help monoecious plants prevent inbreeding? -Male and female gametes produced by the same plant have different number of chromosomes. -Self-incompatibility genes prevent an individual from mating with itself. -The plants produce many more female flowers than male gametes to ensure some amount of cross-fertilization. -The plants release pollen before stigmata fully mature. -Female flowers grow above male flowers, which keeps pollen from falling down on stigmata of the same plant.

-Self-incompatibility genes prevent an individual from mating with itself. -The plants release pollen before stigmata fully mature. -Female flowers grow above male flowers, which keeps pollen from falling down on stigmata of the same plant.

How does the Red Queen hypothesis explain a fitness benefit of sexual reproduction? -Sexually reproducing organisms carefully choose their partners, so only the fittest individuals mate and produce high quality offspring. -Offspring produced by sexual reproduction are less likely to inherit rare genetic disorders than offspring produced by asexual reproduction. -Species that use sexual reproduction live longer and produce more offspring than species that reproduce asexually. -Sexual reproduction produces genetic variation that allows some offspring to survive evolving parasites.

-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. -Small population size. -High herbivore activity. -High pollinator activity. -Rapid climate change.

-Small population size. -High herbivore activity.

Why does frequency-dependent selection confer a fitness advantage on the less common sex? -The less common sex passes fewer of their genes to the next generation. -The less common sex mates more frequently than the more common sex. -The less common sex produces more offspring per individual on average. -The less common sex has a higher survival rates.

-The less common sex produces more offspring per individual on average.

How does a sequential hermaphrodite limit self-fertilization. -Male flowers are small and inconspicuous, and female flowers are large and showy, so pollinators do not visit both on the same plant. -The plant does not have male and female flowers at the same time. -Some plants grow female flowers and other plants grow male flowers. -The female flower is on the top of the plant, and the male flower is on the bottom of the plant.

-The plant does not have male and female flowers at the same time.

Which sex has a genetic advantage in frequency-dependent selection between sexes? -The sex with the higher frequency. -All of the males. -The sex with the lower frequency. -Always the females.

-The sex with the lower frequency.

Why might self-fertilization be beneficial for a plant? -When there are too many dioecious individuals in a population, self-fertilization becomes beneficial for a monoecious individual. -When environmental conditions are harsh, such as a plant growing in nutrient-poor conditions, or when herbivores have damaged the plant, plants may self fertilize. -When environmental conditions are perfect, plants can afford to self-fertilize. -Only plants with perfect flowers are capable of self-fertilization.

-When environmental conditions are harsh, such as a plant growing in nutrient-poor conditions, or when herbivores have damaged the plant, plants may self fertilize.

Classify the statement about asexual and sexual reproduction as true or false: A diploid parent always passes on two copies of its genes to its offspring during sexual reproduction.

False

Classify the statement about asexual and sexual reproduction as true or false: Hermaphroditic organisms may self-fertilize to reproduce asexually or cross-fertilize to reproduce sexually.

False

Classify the statement about asexual and sexual reproduction as true or false: On average, siblings produced asexually share about 50% of their DNA sequence with each other.

False

Classify the descriptions of mating strategies as promiscuity, polygyny, polyandry, or monogamy: A single male and a single female form a persisting social bond.

Monogamy

Classify the descriptions of mating strategies as promiscuity, polygyny, polyandry, or monogamy: This strategy evolves when males and females both make significant contributions to offspring survival.

Monogamy

Classify the descriptions of mating strategies as promiscuity, polygyny, polyandry, or monogamy: A single female mates with more than one male.

Polyandry

Classify the descriptions of mating strategies as promiscuity, polygyny, polyandry, or monogamy: This strategy evolves when a female attempts to acquire genetically superior sperm or receives other benefits from multiple matings.

Polyandry

Classify the descriptions of mating strategies as promiscuity, polygyny, polyandry, or monogamy: A single male mates with more than one female.

Polygyny

Classify the descriptions of mating strategies as promiscuity, polygyny, polyandry, or monogamy: This strategy evolves when a male defends a group of females or a patchy resource the females need.

Polygyny

Classify the descriptions of mating strategies as promiscuity, polygyny, polyandry, or monogamy: Individuals mate with multiple partners without forming social bonds.

Promiscuity

Classify the statement about asexual and sexual reproduction as true or false: Harmful alleles may only be inherited by some offspring during sexual reproduction.

True

Classify the statement about asexual and sexual reproduction as true or false: Individuals may engage in costly or risky social behavior when reproducing sexually.

True

Classify the statement about asexual and sexual reproduction as true or false: Offspring may be produced from vegetative tissues of the parent in asexual reproduction.

True