Deck 11: Sexual Selection

Question 1

The differences between males and females of a species are called ________.

A) sexual morphism
B) male/female dimorphism
C) sexual differentiation
D) sexual dimorphism

Answer 1

D

Question 2

Selection for the ability to successfully compete with members of their own sex to mate with opposite sex is termed ________.

A) mating selection
B) competitive selection
C) intrasexual selection
D) intersexual selection

Answer 2

C

Question 3

In general,when sexual selection is strong for one sex and weak for the other,we can predict that members of the sex subject to strong sexual selection will be ________,and members of the sex subject to weak sexual selection will be ________.

A) choosy; competitive
B) aggressive; passive
C) competitive; showy
D) competitive; choosy

Answer 3

D

Question 4

Small,nonterritorial male marine iguanas typically have their mating interrupted by larger males prior to ejaculation.What alternative mating strategy have these small males developed to compensate for this?

A) Small males form coalitions and distract larger males to allow enough time for copulation.
B) Small males induce ejaculation prior to copulation, and store the ejaculate in their cloacal pouches.
C) Small males have developed the ability to induce ejaculation much more quickly than large males.
D) Small males have developed sperm that are more efficient at fertilization than the sperm of larger males.

Question 5

Experiments by Steve Tanner and colleagues (2000)with gray tree frogs demonstrated that female frogs preferentially mated with male frogs exhibiting ________.

A) many short, repetitive calls over single long calls
B) longer calls rather than shorter calls
C) larger body size over small body size
D) louder calls over softer calls
E) trilling calls over constant calls

Question 6

Which of the following has NOT been observed as a trait of sperm competition?

A) applying pheromones that reduce the female's attractiveness
B) the production of large ejaculates containing many sperm
C) depositing a copulatory plug
D) prolonged copulation during mating
E) All of the above have been observed as traits of sperm competition.

Question 7

In male-male combat observed in marine iguanas,why do males tend to grow to sizes that exceed the optimal size for survival?

Question 8

Pawlowski and colleagues (2000)gathered data from over 3,000 Polish men,and investigated the hypothesis that sexual dimorphism in humans is the result of female choice.They found that there was a slight but significant level of sexual selection on ________.

A) the body mass index (BMI) of men in their twenties, thirties, and forties for both marriage and producing offspring
B) the weight of men in their twenties, thirties, and forties for both marriage and producing offspring
C) the height of men in their twenties, thirties, and forties for both marriage and producing offspring
D) the intelligence quotient (IQ) of men in their twenties, thirties, and forties for both marriage and producing offspring

Question 9

A key event that determines reproductive success involves members of one sex choosing their mates from among the opposite sex,and is termed ________.[two words]

Question 10

Adam Jones and colleagues (2002)demonstrated that in rough-skinned newts,all females tend to mate with at least one male,and often with several.What is the overall mating success for male rough-skinned newts,and what physical characteristic was selected for in males?

Question 11

A mating system in which at least some females mate with more than one male is termed ________.

A) vivapary
B) polygyny
C) polygamy
D) polyandry

Question 12

Adam Jones and colleagues (2000)studied the mating behaviors of broad-nosed pipefish (Syngnathus typhle)in a laboratory situation.For which sex is sexual selection a more potent evolutionary force?

A) females
B) males
C) Both sexes are under equal sexual selection pressure.
D) Neither sex is under sexual selection pressure.

Question 13

The energy and time expended constructing and caring for offspring is known as ________.[two words]

Question 14

Which of the following statements is true regarding the involvement of sexual selection on male function (pollen donation)leading to sexual dimorphism in flowers?

A) Female flowers typically receive far more pollen than is needed to fertilize their seeds.
B) Delph and colleagues (1996) found that out of 42 animal-pollinated plant species, 29% of females had the largest reproductive parts, but males had the largest perianths.
C) Studying wild radishes, Stanton and colleagues (1996) found that reproductive success through pollen donation was limited by pollinator visits, whereas reproductive success through seed production was not.
D) All of the above statements are true.

Question 15

In general,mothers typically make a larger parental investment in each offspring than males do.What is meant by the term parental investment?

Question 16

In studies on the pipefish Nerophis ophidion,females are larger than males and appear to be under greater sexual selection pressure than males.The females have two traits that male pipefish of the species lack.What are these two traits?

A) dark blue stripes and lateral spines
B) bright orange stripes and skin folds on their bellies
C) dark blue stripes and skin folds on their bellies
D) lateral spines and skin folds on their bellies

Question 17

Darwin called differential reproductive success due to variation among individuals in success at getting mates ________.

A) sexual success ratio
B) sexual selection
C) reproductive selection
D) dimorphic selection

Question 18

In his study of the Mediterranean fruit flies (Ceratitis capitata),Matthew Gage (1991)found that ________.

A) males allowed to mate alone produced 2 1/2 times more sperm than those mating in the presence of other males
B) males allowed to mate alone produced 2 1/2 times less sperm than those mating in the presence of other males
C) males produced the same amount of sperm when they were allowed to mate alone or when they mated in the presence of other males
D) males engaged in aggressive behavior when mating in the presence of other males

Question 19

John Hoogland (1998)studied Gunnison's prairie dogs (Cynomys gunnisoni)and observed that an increase in litter size was observed when females ________.

A) chose males that were the largest in the colony
B) mated with more than one male
C) extended the time of copulation with individual males
D) established a large territory for mating

Question 20

Maureen Stanton and colleagues (1986),experimenting with wild radishes (Raphanus raphanistrum),demonstrated that sexual selection on male flowers has led to ________.

A) many small flowers that attract male pollinators
B) showy flowers that attract male pollinators
C) flowers with large nectar-producing glands to attract male pollinators
D) flowers where male and female flowers appear on the same plant

Question 21

Provide an example from the text illustrating the following: If one parent invests in his or her offspring more than the other parent,the heavily investing parent is often limited by resources and time.Also,the lightly investing parent is limited by its access to mates.

Question 22

Explain why male lions,after they have entered a new pride of female lions,will often engage in the practice of infanticide.

Question 23

According to the experiments of Delph and colleagues (1996),is sexual selection often stronger for male or female flowers,and what tends to drive this selection?

Question 24

Describe the experiments performed by Steve Tanner and colleagues (2000)with gray tree frogs to demonstrate the sexual selection they observed.Be sure to comment on the sexual selection that occurs to favor longer male calls,and how the length of calls might indicate male body condition.

Question 25

Natural selection would appear to act against long tails in male red-collared widowbirds,given that longer tails reduce body condition over the mating season.Based on the experiments of Pryke and Andersson (2005),why do long tails appear to be favored despite their obvious disadvantage?

Question 26

Describe the experiments that Adam Jones and colleagues (2002)used with rough-skinned newts to demonstrate the differential relative strength of sexual selection among between males and females.What is the significance that all females tend to mate with at least one male,and often with several males,whereas many of the males failed to mate and many mated only once or twice? Discuss whether sexual selection is a more potent force in the evolution of males or females,and why.

Question 27

When male and female hangflies mate,the number of sperm transferred to the female increases linearly with an increased time of mating.What determines the length of time that male and female hangflies mate?

Question 28

Explain the results of the experiments of Pryke and Andersson (2005)with red-collared widowbirds.Be sure to explain the observations and experiments that were done by these researchers to collect data,and explain why longer tails in males appear to have been under selective pressure,even though the longer tails appear to be detrimental to the overall health of the males.

Question 29

To study sexual dimorphism in humans,Napoleon Chagnon (1988)studied the Yąnomamö,a premodern tribe that live in the Amazon rain forest in Venezuela and Brazil.What specific trait of the Yąnomamö correlated with an increased number of wives a corresponding increased number of children?

Question 30

Describe the unusual pollination system used by orchids of the genus Catasetum,which are pollinated by male euglossine bees.