Chapter 46 Questions

Question 1

Hormones and pheromones both

a. regulate growth, development, and reproduction.
b. travel in the circulatory system from one point in the body to another.
c. transmit signals between animals.
d. bind to specific receptors.

Answer 1

d. bind to specific receptors.

Question 2

The anterior pituitary

a. regulates release of digestive enzymes.
b. acts as a relay in hormone cascades.
c. secretes hormones synthesized in the hypothalamus.
d. acts as the body’s thermostat.

Answer 2

b. acts as a relay in hormone cascades.

Question 3

Suppose you wanted to start an animal-breeding business. For most of the following animals, you could start out with just a single animal. Which of the animals below would require that you start with at least two individuals?

a. frogs
b. sea anemones
c. tapeworms
d. stony corals
e. whiptail lizards in the genus Aspidoscelis

Answer 3

a. frogs

Question 4

Sexual reproduction includes a reproductive pattern called _____.

a. hermaphroditism
b. fragmentation
c. budding
d. fission
e. regeneration

Answer 4

a. hermaphroditism

Question 5

Salamander and insect populations consisting only of genetically identical females lack males because _____.

a. a sex-linked, dominant, lethal mutation is fixed in the population
b. males are killed at birth by their mothers
c. sperm do not fuse with eggs during reproduction, but the eggs develop into embryos anyway
d. a mutation in the population has eliminated the salamander equivalent of the Y chromosome
e. these ancient forms preceded sexual evolution

Answer 5

c. sperm do not fuse with eggs during reproduction, but the eggs develop into embryos anyway

Question 6

Animals utilizing external fertilization are typically _____.

a. insects
b. animals that reproduce asexually
c. land animals
d. mammals
e. aquatic animals

Answer 6

e. aquatic animals

Question 7

The most primitive vertebrates whose reproductive pattern includes the amniotic eggs are the _____.

a. amphibians
b. birds
c. mammals
d. bony fish
e. reptiles

Answer 7

e. reptiles

Question 8

Which of the following correctly traces the path of sperm from their site of production to their exit from a man’s body?

a. epididymis → seminiferous tubule → vas deferens → urethra
b. seminiferous tubule → epididymis → vas deferens → urethra
c. epididymis → urethra → seminiferous tubule → vas deferens
d. seminiferous tubule → vas deferens → epididymis → urethra
e. vas deferens → epididymis → urethra → seminiferous tubule

Answer 8

b. seminiferous tubule → epididymis → vas deferens → urethra

Question 9

In humans, oogenesis in comparison to spermatogenesis is different in that _____.

a. oocyte production works best at cooler temperatures than those that support spermatogenesis
b. oogenesis continues throughout life, but spermatogenesis typically ends at age 55 years
c. oogenesis does not complete meiosis until after fertilization, but spermatogenesis is complete before the sperm leave the body
d. female puberty typically occurs much later than the age of male puberty
e. the names and chemical identities of the pituitary hormones are completely different between males and females

Answer 9

c. oogenesis does not complete meiosis until after fertilization, but spermatogenesis is complete before the sperm leave the body

Question 10

The anatomical location for the typical union of a sperm and an egg (conception) is the _____.

a. vagina
b. ovaries
c. oviducts
d. clitoris
e. uterus

Answer 10

c. oviducts

Question 11

Human pregnancy is indicated by the presence of chorionic-gonadotropin metabolites in the urine until _____.

a. the placenta takes over for the ovaries in producing the steroid hormones needed during pregnancy
b. the end of parturition
c. the child is delivered (born)
d. the fetus grows to about 3-3.5 kg
e. 48 hours after conception

Answer 11

a. the placenta takes over for the ovaries in producing the steroid hormones needed during pregnancy

Question 12

Which of the following characterizes parthenogenesis?

a. An individual may change its sex during its lifetime.
b. Specialized groups of cells grow into new individuals.
c. An egg develops without being fertilized.
d. Both mates have male and female reproductive organs.
e. An organism is first a male and then a female.

Answer 12

c. An egg develops without being fertilized.

Question 13

In male mammals, excretory and reproductive systems share

a. the seminal vesicle.
b. the vas deferens.
c. the prostate.
d. the testes.
e. the urethra.

Answer 13

e. the urethra.

Question 14

Peaks of LH and FSH production occur during

a. the period just before ovulation.
b. the beginning of the follicular phase of the ovarian cycle.
c. the menstrual flow phase of the uterine cycle.
d. the secretory phase of the menstrual cycle.
e. the end of the luteal phase of the ovarian cycle.

Answer 14

a. the period just before ovulation.

Question 15

During human gestation, rudiments of all organs develop

a. in the first trimester.
b. while the embryo is in the oviduct.
c. in the second trimester.
d. in the third trimester.
e. during the blastocyst stage.

Answer 15

a. in the first trimester.

Question 16

Which of the following is a true statement?

a. The endometrial lining is shed in menstrual cycles but reabsorbed in estrous cycles.
b. Estrous cycles are more frequent than menstrual cycles.
c. Estrous cycles are not controlled by hormones.
d. Ovulation occurs before the endometrium thickens in estrous cycles.
e. All mammals have menstrual cycles.

Answer 16

a. The endometrial lining is shed in menstrual cycles but reabsorbed in estrous cycles.

Question 17

For which of the following is the number the same in human males and females?

a. interruptions in meiotic divisions
b. different cell types produced by meiosis
c. functional gametes produced by meiosis
d. meiotic divisions required to produce each gamete

Answer 17

d. meiotic divisions required to produce each gamete

Question 18

Select the correct statement about reproduction and eukaryotic life cycles.

a. In all eukaryotic life cycles, the products of meiosis are gametes.
b. Some animal adults are haploid.
c. Animal reproduction is exclusively sexual.

Answer 18

b. Some animal adults are haploid.

Question 19

What is the “twofold” cost of sex?

a. The cost of producing sexual structures and sex hormones
b. The cost of finding and courting a mate
c. The higher number of female offspring produced by an asexual female

Answer 19

c. The higher number of female offspring produced by an asexual female

Question 20

Identify the role(s) of follicle-stimulating hormone (FSH) in human reproduction.
Select all that apply.
a. FSH stimulates the growth of new follicles in the ovary.
b. FSH promotes the activity of Sertoli cells, which nourish sperm developing within seminiferous tubules.
c. FSH triggers ovulation.

Answer 20

a. FSH stimulates the growth of new follicles in the ovary.

b. FSH promotes the activity of Sertoli cells, which nourish sperm developing within seminiferous tubules.

Question 21

Which of the following characterizes parthenogenesis?

a. An individual may change its sex during its lifetime.
b. Specialized groups of cells grow into new individuals.
c. An organism is first a male and then a female.
d. An egg develops without being fertilized.

Answer 21

d. An egg develops without being fertilized.

Question 22

In male mammals, excretory and reproductive systems share

a. the vas deferens.
b. the urethra.
c. the seminal vesicle.
d. the prostate.

Answer 22

b. the urethra.

Question 23

Which of the following is not properly paired?

a. seminiferous tubule—cervix
b. vas deferens—oviduct
c. testosterone—estradiol
d. scrotum—labia majora

Answer 23

a. seminiferous tubule—cervix

Question 24

Peaks of LH and FSH production occur during

a. the menstrual flow phase of the uterine cycle.
b. the beginning of the follicular phase of the ovarian cycle.
c. the period just before ovulation.
d. the secretory phase of the uterine cycle.

Answer 24

c. the period just before ovulation.

Question 25

During human gestation, rudiments of all organs develop

a. in the first trimester.
b. in the second trimester.
c. in the third trimester.
d. during the blastocyst stage.

Answer 25

a. in the first trimester.

Question 26

Which of the following is a true statement?

a. All mammals have menstrual cycles.
b. The endometrial lining is shed in menstrual cycles but reabsorbed in estrous cycles.
c. Estrous cycles are more frequent than menstrual cycles.
d. Ovulation occurs before the endometrium thickens in estrous cycles.

Answer 26

b. The endometrial lining is shed in menstrual cycles but reabsorbed in estrous cycles.

Question 27

For which of the following is the number the same in human males and females?

a. interruptions in meiotic divisions
b. functional gametes produced by meiosis
c. meiotic divisions required to produce each gamete
d. different cell types produced by meiosis

Answer 27

c. meiotic divisions required to produce each gamete

Question 28

Which statement about human reproduction is false?

a. Fertilization occurs in the oviduct.
b. Spermatogenesis and oogenesis require different temperatures.
c. An oocyte completes meiosis after a sperm penetrates it.
d. The earliest stages of spermatogenesis occur closest to the lumen of the seminiferous tubules.

Answer 28

d. The earliest stages of spermatogenesis occur closest to the lumen of the seminiferous tubules.

Question 29

An advantage of internal fertilization over external fertilization is that _____.

a. internal fertilization allows animals to reproduce sexually
b. internal fertilization requires much less expenditure of resources
c. internal fertilization produces more offspring, ensuring rapid population growth
d. internal fertilization prevents the drying out of gametes in a dry environment

Answer 29

d. internal fertilization prevents the drying out of gametes in a dry environment

Question 30

Spermatogenesis and oogenesis differ in that _____.

a. oogenesis produces one haploid cell and spermatogenesis produces four
b. oogenesis begins at the onset of puberty
c. spermatogenesis begins in the embryonic stage of development
d. oogenesis produces one egg and spermatogenesis produces four sperm
e. a and d

Answer 30

e. a and d

Question 31

A blood sample taken from a woman in her 40s showing high levels of estrogen, progesterone, hCG, and prolactin suggests that _____.

a. she will ovulate within one week
b. she has not been sexually active for several months
c. she is pregnant
d. she is undergoing early menopause

Answer 31

c. she is pregnant

Question 32

An infant suckling on the breast of a woman who has recently given birth sends a nerve impulse to the pituitary gland. The pituitary gland then secretes oxytocin, which stimulates the mammary glands in the breasts to release milk. What type of hormonal feedback is this?

a. negative feedback
b. positive feedback

Answer 32

b. positive feedback

Question 33

Diploidy is first reestablished following _____.

a. fertilization
b. gastrulation
c. parthenogenesis
d. organogenesis
e. ovulation

Answer 33

a. fertilization

Question 34

In humans, oogenesis is completed _____.

a. after ovulation, but before the sperm enters the oocyte
b. after the nuclei of the sperm and egg fuse
c. once the sperm penetrates the oocyte
d. prior to ovulation
e. during embryonic development

Answer 34

c. once the sperm penetrates the oocyte

Question 35

Cleavage of the zygote begins in the _____.

a. ovary
b. uterus
c. vagina
d. oviduct
e. endometrium

Answer 35

d. oviduct

Question 36

In humans, the _____ of the sperm enter(s) the oocyte.

a. nucleus
b. nucleus and mitochondria
c. mitochondria
d. nucleus, mitochondria, and flagellum

Answer 36

a. nucleus

Question 37

What is the variation in sexual reproduction that takes place as a result of the death of the last male bluehead wrasse (Thalassoma bifasciatum) in a harem?

a. The largest female transforms into a male, producing sperm.
b. Parthenogenesis takes place, allowing egg development without fertilization.
c. Individuals are born with both male and female reproductive systems.
d. Self-fertilization takes place.
e. Binary fission allows the parent to produce two identical individuals.

Answer 37

a. The largest female transforms into a male, producing sperm.

Question 38

What is the function of follicle-stimulating hormone (FSH) in the male?

a. FSH stimulates Sertoli cells in seminiferous tubules to nourish sperm.
b. FSH causes Leydig cells to produce testosterone.
c. FSH and inhibin modulate androgen levels by positive feedback.
d. FSH is a precursor hormone to testosterone.

Answer 38

a. FSH stimulates Sertoli cells in seminiferous tubules to nourish sperm.

Question 39

All of the following are methods to effectively prevent conception except _____.

a. birth control pills
b. ​​​coitus interruptus
c. tubal ligation
d. barrier devices with spermicidal jelly
e. IUDs

Answer 39

b. ​​​coitus interruptus

Question 40

Causes of infertility in males or females wishing to conceive may include all of the following except _____.

a. STDs
b. Klinefelter syndrome
c. vasectomy
d. low sperm or egg number
e. improperly formed or blocked ducts

Answer 40

c. vasectomy

Question 41

On a submarine expedition to the ocean bottom, you discover a population of fish that are only female. What type of reproduction does this fish most likely use?

a. cloning
b. parthenogenesis
c. budding
d. sexual

Answer 41

b. parthenogenesis

Question 42

Sexual reproduction ___.

a. results in over half of the offspring being female
b. is completed more rapidly than asexual reproduction
c. is better suited to environments with relatively constant conditions
d. produces offspring of greater genetic variety compared to offspring resulting from asexual reproduction

Answer 42

d. produces offspring of greater genetic variety compared to offspring resulting from asexual reproduction

Question 43

Environmental cues that influence the timing of reproduction generally do so by ___.

a. providing access to water for external fertilization
b. direct effects on hormonal control mechanisms
c. increasing ambient temperature most favorable for sex
d. increasing the body temperature

Answer 43

b. direct effects on hormonal control mechanisms

Question 44

In an animal that switches between sexual and asexual reproduction, when is sexual reproduction more likely to occur?

a. when conditions for survival are favorable
b. when males and females find each other
c. when conditions for survival are unfavorable
d. What conditions favor sexual over asexual remains a complete mystery.

Answer 44

c. when conditions for survival are unfavorable

Question 45

Sexual reproduction ___.

a. guarantees that both parents will provide care for each offspring
b. enables males and females to remain isolated from each other while rapidly colonizing habitats
c. can produce diverse phenotypes that may enhance survival of a population in a changing environment
d. allows animals to conserve resources and reproduce only during optimal conditions

Answer 45

c. can produce diverse phenotypes that may enhance survival of a population in a changing environment

Question 46

Animals that have external fertilization are most likely to reproduce in which of the following areas?

a. shallow lake
b. tallgrass prairie
c. sand dune
d. polar ice sheet

Answer 46

a. shallow lake

Question 47

In close comparisons, external fertilization often yields more offspring than does internal fertilization. However, internal fertilization typically offers the advantage that ___.

a. it permits the most rapid population increase
b. the smaller number of offspring produced often receive a greater amount of parental investment
c. it requires expression of fewer genes and maximizes genetic stability
d. it requires less time and energy to be devoted to reproduction

Answer 47

b. the smaller number of offspring produced often receive a greater amount of parental investment

Question 48

You decide to study two species of birds, both of which form monogamous pairs (one male and one female). In species 1, you find that the eggs in a pair’s nest are in fact almost always the offspring of that pair. In species 2, you are surprised to find that many of the eggs in a nest were actually fathered by males of neighboring pairs. Apparently, mating outside of monogamous pairings is widespread in species 2. What would you expect to observe if you examined the reproductive tracts of the female birds in the species?

a. Females of species 1 would produce more oocytes.
b. Females of species 2 would have sperm from multiple males in their reproductive tracts.
c. Ovaries of species 1 are larger than those of species 2.
d. Females of species 1 would have sperm from multiple males in their reproductive tracts, but would only use their partners’ sperm to fertilize eggs.

Answer 48

b. Females of species 2 would have sperm from multiple males in their reproductive tracts.

Question 49

Egg laying in fruit flies can be triggered (induced) when males deposit their sperm in the spermathecae of the females. What is the selective advantage of induced egg laying for the male flies?

a. More eggs can be fertilized at once when egg laying is induced.
b. Induced egg laying ensures that a male fly’s sperm is used for fertilization.
c. Mating takes less time, so less energy is expended by the males.
d. Because egg laying is induced upon mating, the males do not have to produce as much sperm.

Answer 49

b. Induced egg laying ensures that a male fly’s sperm is used for fertilization.

Question 50

Which of the following are similar between spermatogenesis and oogenesis in vertebrate animals? Both oogenesis and spermatogenesis ___.
I. begin at the onset of sexual maturity
II. result in the production of four functional haploid cells from one diploid cell
III. leads to the production of gametes from germ cells
IV. are complete at the time of birth
a. Only III
b. Both II and III
c. Both I and II
d. Both III and IV

Answer 50

a. Only III

Question 51

Mature human sperm and ova are similar in that they ___.

a. both have the same number of chromosomes
b. each have a flagellum that provides motility
c. are produced from puberty until death
d. are approximately the same size

Answer 51

a. both have the same number of chromosomes

Question 52

The surgical removal of the seminal vesicles would likely ___.

a. greatly reduce the volume of semen
b. cause the testes to migrate back into the abdominal cavity
c. cause sterility because sperm would not be produced
d. cause sterility because sperm would not be able to exit the body

Answer 52

a. greatly reduce the volume of semen

Question 53

Increasing the temperature of the human scrotum by 2 degrees Celsius (that is, near the normal body core temperature) and holding it there would most likely ___.

a. increase the fertility of the affected man by enhancing the rate of steroidogenesis
b. reduce the fertility of the man by impairing spermatogenesis
c. reduce the fertility of the man by impairing the production of gonadal steroid hormones
d. reduce the man’s sexual interest

Answer 53

b. reduce the fertility of the man by impairing spermatogenesis

Question 54

Which statement about human reproduction is correct?

a. A human oocyte only completes meiosis II after a sperm penetrates it.
b. In humans, spermatogenesis and oogenesis both function best at normal, core body temperatures.
c. The earliest stages of spermatogenesis occur closest to the lumen of the seminiferous tubules.
d. Spermatogonia and oogonia are haploid cells.

Answer 54

a. A human oocyte only completes meiosis II after a sperm penetrates it.

Question 55

A physician finds that a nine-year-old male patient is entering puberty much earlier than usual. Such a condition is most likely the result of a tumor in the ___.

a. testes, producing elevated levels of estrogen
b. hypothalamus, producing elevated levels of testosterone
c. anterior pituitary, producing elevated levels of testosterone
d. anterior pituitary, producing elevated levels of gonadotropins

Answer 55

d. anterior pituitary, producing elevated levels of gonadotropins

Question 56

An inactivating mutation in the progesterone receptor gene would likely result in ___.

a. enlarged and hyperactive uterine endometrium
b. the absence of secondary sex characteristics
c. the inability of the uterus to support pregnancy
d. the absence of mammary gland development

Answer 56

c. the inability of the uterus to support pregnancy

Question 57

For your internship at the local zoo, you have been assigned to help with the new orangutan-breeding program. Little is known about orangutan reproductive hormones, but hormone feedback cycles are often the same in closely related animals. You have been asked to use your knowledge of the interactions of human reproductive hormones to recommend injections to promote ovulation in a female orangutan when a visiting male arrives for a brief breeding visit.
Which of the following hormones would you use if you want to induce ovulation right away?
a. estradiol (estrogen)
b. progesterone
c. follicle-stimulating hormone (FSH)
d. luteinizing hormone (LH)

Answer 57

d. luteinizing hormone (LH)

Question 58

Labor contractions can be increased by the medical use of a synthetic drug that mimics the action of ___.

a. luteinizing hormone
b. prolactin
c. inhibin
d. oxytocin

Answer 58

d. oxytocin

Question 59

Once uterine contractions have begun, the female body releases several hormones that act in a positive feedback loop. The purpose of this feedback loop is ___.

a. decrease the number of oxytocin receptors in the uterus
b. to promote the development of a new follicle
c. inhibit the release of prostaglandins
d. to ensure continued contractions until labor is complete

Answer 59

d. to ensure continued contractions until labor is complete

Question 60

An ectopic pregnancy occurs when a fertilized egg implants somewhere other than in the lining of the uterus. Usually it implants in the oviduct. Which of the following would be most likely explanation for such a pregnancy being unsuccessful?

a. The orientation of the baby would be sideways.
b. The necessary hormones cannot reach the developing fetus in the oviduct.
c. The lining of the oviduct is unable to support the developing fetus.
d. Human chorionic gonadotropin (hCG) cannot be produced in the oviduct.

Answer 60

c. The lining of the oviduct is unable to support the developing fetus.