Chapter 8

Question 1

The progeny produced by sexual reproduction are:A) genetically different from one another. D) genetically identical to their parents.B) genetically different from their parents. E) Both A and B are correct.C) genetically identical to one another. F) Both C and D are correct.

Answer 1

E) Both A and B are correct.

Question 2

Asexual reproduction is quite common in plants. Most plant cells retain the ability to producean entire new individual, as is the case when new shoots sprout from roots or rhizomes, oreven the margins of leaves. Such asexual reproduction is referred to as:A) parthenogenesisB) selfingC) vegetative reproductionD) asexual selection

Answer 2

C) vegetative reproduction

Question 3

Because the process of asexual reproduction does not involve genetic contributions from twoindividuals, meiosis is never involved.A) True B) False

Answer 3

B) False

Question 4

Asexual reproduction is found in all major groups of animals except:A) hydroids. B) corals. C) insects. D) fishes and reptiles. E) birds and mammals.

Answer 4

E) birds and mammals.

Question 5

The progeny of a sexual union contribute only one‐half as much to the evolutionary fitness ofeither parent as asexually produced offspring. This relative reduction in fitness is called__________.A) the Red Queen hypothesis C) sequential hermaphroditismB) the twofold cost of meiosis D) dioecism

Answer 5

B) the twofold cost of meiosis

Question 6

Which of the following will exactly negate the cost to a female of sexual reproduction?A) Male parental investment halves the number of offspring that a female could rear on herown.B) Male parental investment doubles the number of offspring that a female could rear on herown.C) Male parental investment triples the number of offspring that a female could rear on herown.D) Male parental investment quadruples the number of offspring that a female could rear onher own.

Answer 6

B) Male parental investment doubles the number of offspring that a female could rear on herown.

Question 7

The high fitness cost of sexual reproduction may be offset by the advantage of producinggenetically varied offspring because the environment itself varies over time or space.A) TrueB) False

Answer 7

A) True

Question 8

Most cases of asexual reproduction in complex animals (fishes, amphibians, reptiles) appear inspecies that belong to genera in which other species are sexual. This sporadic distribution ofasexual reproduction indicates that:A) the long‐term evolutionary potential of asexual species is low.B) the long‐term evolutionary potential of asexual species is high.

Answer 8

A) the long‐term evolutionary potential of asexual species is low.

Question 9

The bdelloid rotifers are unusual in that they are a moderately diverse group of organisms thatseems to have reproduced only asexually for tens of millions of years. How have these speciesmaintained diversity in their gene pool?A) by occasional sexual reproductionB) by occasional hybridization with other kinds of rotifersC) by living in unvarying environmentsD) by maintaining altered copies of a duplicated gene that code for functionally differentproteins

Answer 9

D) by maintaining altered copies of a duplicated gene that code for functionally differentproteins

Question 10

From a phylogenetic perspective, asexual species of complex animals (fishes, amphibians,reptiles):A) appear to have a long evolutionary history.B) belong to genera in which many other species are also asexual.C) probably do not persist for long periods.D) All of the above are true.

Answer 10

C) probably do not persist for long periods.

Question 11

Compared to their hosts, pathogens typically evolve:A) more slowly.B) at about the same rate.C) more rapidly.D) None of the above—pathogens are incapable of evolving.

Answer 11

C) more rapidly.

Question 12

What is the key evolutionary concept underlying the Red Queen hypothesis?A) Through sex and genetic recombination, hosts present a moving target for evolvingpathogens.B) Through sex and genetic recombination, hosts prevent evolution of pathogens.C) Through sex and genetic recombination, hosts are able to stop evolving and still maintainhigh fitness.D) All of the above are true.

Answer 12

A) Through sex and genetic recombination, hosts present a moving target for evolvingpathogens.

Question 13

Curt Lively and coworkers at Indiana University have studied coevolution between snails andtheir trematode worm parasites. They found that when the prevalence of infection was high:A) males made up about 50% of the populations, indicating that all reproduction was sexual.B) males were common, indicating relatively high rates of sexual reproduction.C) males were uncommon, indicating relatively low rates of sexual reproduction.D) males were absent, indicating a lack of sexual reproduction.

Answer 13

B) males were common, indicating relatively high rates of sexual reproduction.

Question 14

What did Curt Lively and coworkers find when they experimentally infected populations ofsnails taken from various depths in a lake, using trematode worm parasites also taken fromvarious depths?A) Snails taken from a particular depth were most readily infected by parasites from otherdepths.B) Snails taken from a particular depth were most readily infected by parasites from the samedepth.C) Snails taken from a particular depth were infected about equally well by parasites from anydepth.D) There was a surprising lack of infection in any of the experimental combinations of snailsand parasites.

Answer 14

B) Snails taken from a particular depth were most readily infected by parasites from the samedepth.

Question 15

Curt Lively and coworkers found that four common clones of snails from a shallow lake in NewZealand varied in abundance over a four‐year period; increases in population size of anyparticular clone were followed by marked increases in the rate of parasitism. What evolutionaryprocess was responsible for these phenomena?A) balancing selection C) purifying selectionB) directional selection D) frequency‐dependent selection

Answer 15

D) frequency‐dependent selection

Question 16

Hermaphroditic snails and most worms typically exhibit __________ male and female sexualfunctions.A) simultaneous B) sequential C) partial D) dioecious

Answer 16

A) simultaneous

Question 17

Which of the following plant species would be considered hermaphroditic?A) one that is strictly dioecious D) A and BB) one that is strictly monoecious E) B and CC) one that has only perfect flowers

Answer 17

E) B and C

Question 18

Under which of the following conditions is hermaphroditism likely to arise in a species in whichthe individuals have only one sexual function (male or female)?A) Adding male function results in a proportionately smaller loss of female function.B) Adding female function results in a proportionately smaller loss of male function.C) both A and BD) neither A nor B

Answer 18

C) both A and B

Question 19

Having separate sexes is favored when individual gains in fitness from adding a second sexualfunction bring about even greater losses in the original sexual function. Such would be the casewhen:A) adding either sexual function requires additional complex anatomical structures.B) maleness requires specializations for mate attraction and combat with other males.C) femaleness requires specializations for egg production or brood care.D) all of the above

Answer 19

D) all of the above

Question 20

Which of the following describes the predominant condition in flowering plants?A) Most plant species are monoecious.B) Most plant species are dioecious.C) Most plant species are perfect‐flowered hermaphrodites.D) Most plant species have both hermaphrodites and either male or female individuals.

Answer 20

C) Most plant species are perfect‐flowered hermaphrodites.

Question 21

In a species with an XY sex determination system, the only possible outcome is a 50:50male:female sex ratio.A) TrueB) False

Answer 21

B) False

Question 22

In several species of turtles, lizards, and alligators, sex of an individual is determined by:A) the social environment.B) the temperature at which it develops in the egg.C) the female parent.D) the male parent.

Answer 22

B) the temperature at which it develops in the egg.

Question 23

In the California sheephead, heavy fishing has resulted in which of the following?A) earlier age at maturityB) earlier age of sex switching from female to maleC) both A and BD) neither A nor B

Answer 23

C) both A and B

Question 24

Under which of the following conditions would you expect to find local mate competition?A) Individuals do not disperse far from where they were born.B) Mating takes place among close relatives.C) Mating takes place among the progeny of an individual female.D) all of the above

Answer 24

D) all of the above

Question 25

Which of the following groups would you study if you were interested in finding species withfemale‐biased sex ratios?A) coralsB) large mammalsC) insectivorous birdsD) parasitic waspsE) any species living exclusively on small islands

Answer 25

D) parasitic wasps

Question 26

In which of the following groups are there haplodiploid species, in which females can controlthe sex ratio of their offspring by storing sperm and using it—or not—to fertilize their eggs?A) all insectsB) hymenopterans (bees, ants, and wasps)C) all vertebratesD) birdsE) mammals

Answer 26

B) hymenopterans (bees, ants, and wasps)

Question 27

In species with separate sexes, which sex can enhance more its evolutionary fitness by matingwith many partners of the opposite sex?A) females B) males C) Neither sex has an advantage in this respect.

Answer 27

B) males

Question 28

Of the two possible kinds of polygamy, which is by far the more common in animals?A) polyandry (one female forms long‐term bonds with more than one male)B) polygyny (one male forms long‐term bonds with more than one female)

Answer 28

B) polygyny (one male forms long‐term bonds with more than one female)

Question 29

Although many species of birds were thought to be strictly monogamous, this idea has beenchallenged recently by the discovery that __________ are quite common.A) hermaphroditic individuals C) female‐biased sex ratiosB) intergeneric matings D) extra‐pair copulations

Answer 29

D) extra‐pair copulations

Question 30

In gynodioecious plants, hermaphrodites and females exist in the same populations. In manysuch cases, the genes that cause male sterility (and thus result in plants that are essentiallyfemale) are transmitted only through female gametes, because such genes are found in the__________.A) pollenB) nucleusC) cytoplasm, within chloroplastsD) cytoplasm, within vacuoles

Answer 30

C) cytoplasm, within chloroplasts

Question 31

You are studying a species of bird that is often monogamous but sometimes exhibits polygyny.You have the choice of studying this species in several different habitats. Which of the followingwill you choose if you want a high probability of finding polygyny?A) a habitat in which territory qualities are nearly identicalB) a habitat in which territory qualities vary somewhatC) a habitat in which territory qualities are highly variableD) a habitat unsuitable for the formation of territories

Answer 31

C) a habitat in which territory qualities are highly variable

Question 32

Part of the fundamental asymmetry of life in species having separate sexes is that __________typically exercise the greater degree of choice in selection of mates.A) females B) males

Answer 32

A) females

Question 33

What happened when the tails of male widowbirds were artificially elongated?A) These males were more successful in attracting mates than males with normal tails.B) These males were less successful in attracting mates than males with normal tails.C) These males were about equally successful in attracting mates as males with normal tails.

Answer 33

A) These males were more successful in attracting mates than males with normal tails.

Question 34

Hamilton and Zuk proposed in 1982 that showy plumage in males might provide individualshaving superior genotypes an opportunity to display which trait to potential mates?A) great physical strength C) resistance to parasitesB) superior intelligence D) extended life span

Answer 34

C) resistance to parasites

Question 35

Support for the Hamilton‐Zuk hypothesis has come from which of the following observations?A) Male elk with larger antlers often defeat males with smaller antlers.B) Larger male elephant seals are more successful in establishing harems.C) Male cardinals with larger territories are more likely to attract multiple mates.D) Female feral rock doves preferred clean to parasite‐infested males by a ratio of 3:1.

Answer 35

D) Female feral rock doves preferred clean to parasite‐infested males by a ratio of 3:1.

Question 36

In the typical process of sexual reproduction, gametes from two individuals unite to form asingle cell called a __________.

Answer 36

zygote

Question 37

The __________ cell products of meiosis contain a full complement of chromosomes, butcontain only one member of each chromosome pair present in diploid cells.

Answer 37

haploid

Question 38

__________ are marine animals that reproduce asexually, often forming massive underseacolonies.

Answer 38

corals

Question 39

Hermaphroditic plant species that have, on the same individual, separate flowers having maleor female sexual function are referred to as __________.

Answer 39

monoecious

Question 40

Sexual __________ is the usual outcome of sexual selection.

Answer 40

dimorphism

Question 41

Individual traits that advertise an individual’s sex but that are not related to the primary sexualorgans are called __________ sexual characteristics.

Answer 41

secondary

Question 42

In 1871,__________ published a book entitled The Descent of Man and Selection in Relation toSex, in which he was the first to propose the idea of sexual selection.

Answer 42

Charles Darwin

Question 43

Female preferences in mate selection can lead to the evolution of seemingly outlandishornamentation and displays among males in a process that has been dubbed __________sexual selection.

Answer 43

runaway

Question 44

__________ is a common phenomenon in male birds faced with the constant threat of extraterritorialcopulations.

Answer 44

Mate guarding

Question 45

The wheatear, a small European songbird, decorates its nesting ledge with up to 2 kg of smallstones in a display that seems a perfect example of the __________ principle of sexual selectionproposed by Israeli biologist Amotz Zahavi.

Answer 45

handicap