Chapter 47

Asexual reproduction results in offspring that are genetically identical to their parent. What type of cell process commonly occurs to generate this type of offspring? A) mitosis B) spermatogenesis C) cell fusion D) oogenesis

Which of the following is most TRUE of sexual reproduction? A) Sexual reproduction allows for more rapid population growth than does asexual reproduction. B) Only half of the offspring from sexually reproducing females are also females. C) Asexual reproduction produces offspring of greater genetic variety. D) Sexual reproduction is completed more rapidly than asexual reproduction. E) Asexual reproduction is better suited to environments with extremely varying conditions.

Which of the following correctly describes the reproduction of males in Daphnia? A) Daphnia males are produced asexually from unfertilized eggs. B) Daphnia males are produced sexually through fertilization of eggs but are sterile from birth. C) Daphnia males are produced from a pseudosexual union of two eggs. D) Daphnia males are produced asexually but are sterile from birth.

Why was it informative for researchers to study the proximate causation of Daphnia switching reproductive tactics in the laboratory? A) Daphnia in the wild were genetically identical and the laboratory was the only place where Daphnia would reproduce sexually. B) Daphnia could not obtain enough energy in the wild to reproduce sexually. C) Daphnia were no longer available in the wild when the investigations occurred. D) The density of Daphnia populations could be easily manipulated in the laboratory.

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 conditions for survival are unfavorable C) when males and females find each other D) What conditions favor sexual over asexual reproduction remains a complete mystery.

An advantage of asexual reproduction is that it ________. A) allows the species to endure long periods of unstable environmental conditions B) enhances genetic variability in the species C) enables the species to flourish in stable habitats that are favorable to that species D) produces offspring that respond effectively to new pathogens E) allows a species to easily rid itself of harmful mutations

The fibrous layer that surrounds an oocyte is called the ________. A) vitelline envelope B) jelly layer C) corona radiate D) plasma membrane E) acrosome

Asexual reproduction results in greater reproductive success than does sexual reproduction when ________. A) pathogens are rapidly diversifying B) a species has accumulated numerous deleterious mutations C) there is some potential for rapid overpopulation D) a species is expanding into diverse geographic settings E) a species is in stable and favorable environments

Sexual reproduction ________. A) allows animals to conserve resources and reproduce only during optimal conditions B) can produce diverse phenotypes that may enhance survival of a population in a changing environment C) yields more numerous offspring more rapidly than is possible with asexual reproduction D) enables males and females to remain isolated from each other while rapidly colonizing habitats E) guarantees that both parents will provide care for each offspring

All individuals of a particular species of whiptail lizards are females. Their reproductive efforts depend on ________. A) fertilization of their eggs by males of other lizard species B) gonadal structures that only undergo mitosis C) parthenogenesis D) budding prior to the development of a sexual phenotype E) fission of diploid gametes

For water fleas of the genus Daphnia, switching from a pattern of asexual reproduction to sexual reproduction coincides with ________. A) environmental conditions becoming more favorable for offspring B) greater abundance of food resources for offspring C) periods of temperature or food stresses on adults D) completion of puberty E) exhaustion of an individual's supply of eggs

In vertebrate animals, spermatogenesis and oogenesis differ in that ________. A) oogenesis begins at the onset of sexual maturity, whereas spermatogenesis begins during embryonic development B) oogenesis produces four functional haploid cells, whereas spermatogenesis produces only one functional spermatozoon C) the division of cytoplasm is unequal in oogenesis, whereas it is equal in spermatogenesis D) oogenesis ends at menopause, whereas spermatogenesis is finished before birth E) spermatogenesis is not completed until after fertilization occurs, but oogenesis is completed by the time a girl is born

Mature human sperm and ova are similar in that they ________. A) both have the same number of chromosomes B) are approximately the same size C) each have a flagellum that provides motility D) are produced from puberty until death E) are formed before birth

Which of the following is an example of sexual reproduction? A) parthenogenesis in lizards B) budding in sponges C) binary fission in Amoeba D) fertilization in Daphnia

Asexual reproduction results in offspring that are genetically identical to their parent. What type of cell process occurs to generate this type of offspring? A) mitosis B) meiosis C) cell fusion D) gametogenesis

Which of the following correctly describes a difference between spermatogenesis and oogenesis? A) Spermatogenesis results in four mature sperm cells, whereas oogenesis results in one mature egg cell. B) Spermatogenesis results in one mature sperm cell, whereas oogenesis results in four mature egg cells. C) In spermatogenesis, mitosis occurs twice and meiosis once; in oogenesis, mitosis occurs once and meiosis twice. D) In spermatogenesis, mitosis occurs twice and meiosis once; in oogenesis, mitosis occurs once and meiosis twice.

During oogenesis, meiosis results in ________. A) four equally sized cells that stop dividing in meiosis I B) two equally sized cells that are both typically fertilized C) two equally sized cells, but only one that is typically fertilized D) two or three small cells and one large cell that develops further if fertilized

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. E) Both mates have male and female reproductive organs.

For which of the following is the number the same in spermatogenesis and oogenesis? A) gametes produced over the lifetime of an organism B) functional gametes produced by meiosis C) meiotic divisions required to produce each gamete D) gametes produced in a given time period E) different cell types produced by meiosis

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) sexual B) budding C) cloning D) parthenogenesis

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. Given this information, what would be the logical prediction to make before comparing the testes size of males of the two species? A) Testes of species 1 are larger than testes of species 2. B) Testes of species 2 are larger than testes of species 1. C) The testes size of species 1 will increase throughout its lifespan, eventually becoming larger than that of species 2. D) There is no relationship between this observation and the size of testes.

Which statement about human reproduction is correct? A) Fertilization occurs in the uterus. B) In humans, spermatogenesis and oogenesis function best at normal, core body temperatures. C) A human oocyte completes meiosis after a sperm penetrates it. D) The earliest stages of spermatogenesis occur closest to the lumen of the seminiferous tubules.

Among human males, the passage within the penis through which sperm moves is the ________. A) vas deferens B) urinary bladder C) seminal vesicle D) urethra E) ureter

Internal and external fertilization both ________. A) produce single-celled zygotes B) occur only among invertebrates C) occur only among terrestrial animals D) depend on the use of copulatory organs E) occur only among birds

Among nonmammalian vertebrates, the cloaca is an anatomical structure that functions as ________. A) a specialized sperm-transfer device produced only by males B) a shared pathway for the digestive, excretory, and reproductive systems C) a region bordered by the labia minora and clitoris in females D) a source of nutrients for developing sperm in the testes E) a gland that secretes mucus to lubricate the vaginal opening

Contact of a sperm with signal molecules in the jelly layer of an egg causes the sperm to undergo ________. A) mitosis B) depolarization C) apoptosis D) vitellogenesis E) the acrosome reaction

In birds, a shell forms on the egg in the ________, A) uterus B) vagina C) oviduct D) cervix E) cloaca

An oocyte released from a human ovary enters the ________. A) uterus B) vagina C) oviduct D) cervix E) cloaca

The junction of the upper vagina and the uterus is called the ________. A) fallopian tube B) clitoris C) oviduct D) labia majora E) cervix

Among mammals, the male and female genital structures that consist mostly of erectile tissue include the ________. A) penis and clitoris B) vas deferens and oviduct C) testes and ovaries D) seminiferous tubules and hymen E) prostate and ovaries

Human sperm cells develop from spermatogonia in the ________. A) prostate gland B) vas deferens C) testes D) epididymis E) seminal vesicles

The surgical removal of the seminal vesicles would likely ________. A) cause sterility because sperm would not be produced B) cause sterility because sperm would not be able to exit the body C) greatly reduce the volume of semen D) enhance the fertilization potency of sperm in the uterus E) cause the testes to migrate back into the abdominal cavity

Accessory fluids that contribute to the semen are produced by all of the following structures EXCEPT ________. A) prostate gland B) bulbourethral gland C) vas deferens D) seminal vesicle

42) In male mammals, excretory and reproductive systems share the ________. A) testes B) urethra C) seminal vesicle D) vas deferens E) prostate

In the human male reproductive system, secretions from ________ produce molecules that stimulate smooth muscle contractions in the female uterus. A) prostate gland B) seminal vesicles C) bulbourethral gland D) testes

Fertilization of a human egg takes place in the ________. A) ovary B) fallopian tube C) cervix D) vagina E) uterus

At the time of fertilization, the maturation of the human oogonium has resulted in ________. A) one secondary oocyte B) two primary oocytes C) four secondary oocytes D) four primary oocytes E) four zygotes

Sperm cells mature and are stored within human males in the ________. A) urethra B) prostate C) epididymis D) seminal vesicles E) bulbourethral gland

Sperm-egg membrane fusion immediately proceeds in which step in fertilization? A) acrosome reaction B) chemical signaling by egg to attract sperm C) entry of sperm nucleus into egg D) flagellar hyperactivity E) contact of the sperm head with the egg's plasma membrane

Why does external fertilization typically occur much more often in aquatic animals than in terrestrial animals? A) The gametes are hydrophobic, so they must be suspended in water to avoid clumping. B) The gametes must be produced in large numbers, which can occur only in aquatic environments. C) Terrestrial species typically only have one testis, limiting sperm production. D) The gametes must be kept wet to avoid desiccation.

When female fruit flies mate with two different males on the same day, ________. A) the first male's sperm fertilizes all of the eggs B) the first male's sperm fertilizes most of the eggs C) the second male's sperm fertilizes most of the eggs D) the first and second males fertilize equal numbers of eggs E) none of the eggs become fertilized

Animals that have external fertilization are most likely to reproduce in which of the following areas? A) sand dune B) polar ice sheet C) shallow lake D) tallgrass prairie

Ovoviviparous species are distinguished by what trait? A) Offspring are nourished via a placenta prior to live birth. B) Offspring are nourished via the egg's yolk and then hatch from eggs. C) Offspring are nourished via the egg's yolk prior to live birth. D) Offspring receive nourishment from the male parent.

Which of the following represents the correct sequence of events for sexual reproduction in most vertebrates? A) mitosis → zygote → meiosis → gametes → embryo B) meiosis → zygote → mitosis → gametes → embryo C) mitosis → gametes → meiosis → zygote → embryo D) meiosis → gametes → mitosis → zygote → embryo E) meiosis → gametes → zygote → mitosis → embryo

The correct sequence of events in the development of humans and other mammals is ________. A) cleavage, gastrulation, organogenesis, and then formation of a blastula B) gastrulation, formation of a blastula, cleavage, and then organogenesis C) cleavage, formation of a blastula, gastrulation, and then organogenesis D) gastrulation, organogenesis, formation of a blastula, and then cleavage

Cytoplasmic determinants help organize what aspect of the embryo? A) inner cell mass position B) trophoblast fate C) body axes D) brain size

During gastrulation, ________. A) the neural tube forms B) the blastula forms C) somites form D) three germ layers form

During cleavage, the number of cells ________, while the size of individual cells ________. A) increases; increases B) increases; decreases C) decreases; increases D) decreases; decreases

Gastrulation is an important event in early embryonic development. Which of the following is NOT a result of gastrulation? A) formation of three embryonic cell layers B) movement and alignment of many embryonic cells C) the formation of a gastrula D) the formation of specialized adult tissues

Which of the following correctly displays the sequence of developmental milestones? A) blastula → gastrula → cleavage B) blastula → cleavage → gastrula C) cleavage → gastrula → blastula D) cleavage → blastula → gastrula E) gastrula → blastula → cleavage

Cells move to new positions as an embryo establishes its three germ-tissue layers during ________. A) determination B) cleavage C) fertilization D) induction E) gastrulation

The outer-to-inner sequence of tissue layers in a post-gastrulation vertebrate embryo is ________. A) endoderm → ectoderm → mesoderm B) mesoderm → endoderm → ectoderm C) ectoderm → mesoderm → endoderm D) ectoderm → endoderm → mesoderm E) endoderm → mesoderm → ectoderm

If gastrulation was blocked by an environmental toxin, then ________. A) cleavage would not occur in the zygote B) embryonic germ layers would not form C) fertilization would be blocked D) the blastula would not be formed E) the blastopore would form the mouth

The vertebrate ectoderm is the origin of the ________. A) nervous system B) liver C) pancreas D) heart E) kidneys

In frog embryos, the blastopore becomes the ________. A) anus B) ears C) eyes D) nose E) mouth

In a frog embryo, gastrulation ________. A) produces a blastocoel B) occurs prior to cleavage C) is impossible because of the large amount of yolk in the ovum D) proceeds as cells roll over the lip of the blastopore E) occurs within the inner cell mass that is embedded in the large amount of yolk

Which of the following is a correct description of the fate of the germ layers? A) The mesoderm gives rise to the skeletal system. B) The endoderm gives rise to the hair follicles. C) The ectoderm gives rise to the liver. D) The mesoderm gives rise to the lungs.

From earliest to latest, the overall sequence of early development proceeds in which of the following sequences? A) gastrulation → organogenesis → cleavage B) ovulation → gastrulation → fertilization C) cleavage → gastrulation → organogenesis D) gastrulation → blastulation → neurulation E) preformation → morphogenesis → neurulation

Changes in cell position occur extensively during ________. A) organogenesis, but not during gastrulation or cleavage B) cleavage, but not during gastrulation or organogenesis C) fertilization and cleavage, but not during gastrulation D) gastrulation and cleavage E) gastrulation

The fluid-filled cavity within the frog blastula is called the ________. A) blastopore B) mouth C) blastocoel D) anus

The embryonic precursor to the human brain is the ________. A) notochord B) neural tube C) mesoderm D) archenteron E) set of bilateral somites

Somites give rise to all of the following tissues EXCEPT ________. A) bone tissue B) muscle tissue C) nervous tissue D) dermal skin tissue E) connective tissue

Which of the following statements support the hypothesis that the onset of puberty is related to nutritional state? I. On average, puberty occurs at a younger age now than it did 200 years ago. II. Girls with large fat stores generally enter puberty earlier than thin girls do. III. The nutritional state of the U.S. population is much better than it was 200 years ago. A) only I and III B) only II and III C) only I and II D) only II E) I, II, and III

In humans, the follicular cells that remain behind in the ovary following ovulation become ________. A) the ovarian endometrium that is shed at the time of the menses B) the corpus luteum, which secretes the steroid hormones progesterone and estradiol. C) the thickened portion of the uterine wall D) swept into the fallopian tube E) the placenta, which secretes cervical mucus

A primary difference between the estrous and menstrual cycles is that ________. A) the endometrium shed by the uterus during the estrous cycle is reabsorbed with no extensive fluid flow out of the body, whereas the shed endometrium of menstrual cycles is excreted from the body B) behavioral changes during estrous cycles are much less apparent than those of menstrual cycles C) season and climate have less pronounced effects on estrous cycles than they do on menstrual cycles D) copulation normally occurs across the estrous cycle, whereas in menstrual cycles copulation only occurs during the period surrounding ovulation

In correct chronological order, the three phases of the human ovarian cycle are ________. A) menstrual → ovulation → luteal B) follicular → luteal → secretory C) menstrual → proliferative → secretory D) follicular → ovulation → luteal E) proliferative → luteal → ovulation

A contraceptive pill that continuously inhibits the release of gonadotropin-releasing hormone (GnRH) from the hypothalamus will ________. A) increase the production of estrogen and progesterone by the ovaries B) initiate ovulation C) reduce the secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the anterior pituitary gland D) stimulate the secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the posterior pituitary gland E) increase the flow phase of the menstrual cycle

An inactivating mutation in the progesterone receptor gene would likely result in ________. A) the absence of secondary sex characteristics B) the absence of pituitary gonadotropin hormones C) the inability of the uterus to support pregnancy D) enlarged and hyperactive uterine endometrium E) the absence of mammary gland development

A reproductive hormone that is secreted directly from a structure in the brain is ________. A) testosterone B) estradiol C) progesterone D) follicle-stimulating hormone (FSH) E) gonadotropin-releasing hormone (GnRH)

The primary function of the corpus luteum is to ________. A) nourish and protect the egg cell B) produce prolactin in the alveoli C) maintain progesterone and estrogen synthesis after ovulation has occurred D) stimulate the development of the mammary glands E) support pregnancy in the second and third trimesters

For the initial days following ovulation in a nonpregnant menstrual cycle, the main source of progesterone is the ________. A) adrenal cortex B) anterior pituitary C) corpus luteum D) developing follicle E) placenta

Ovulation is the follicular response to a burst of secretion of ________. A) luteinizing hormone (LH) B) progesterone C) inhibin D) prolactin E) estradiol

Prior to ovulation, the primary steroid hormone secreted by the growing follicle is ________. A) luteinizing hormone (LH) B) follicle-stimulating hormone (FSH) C) inhibin D) gonadotropin-releasing hormone (GnRH) E) estradiol

The hypothalamic hormone that stimulates the secretion of sex hormones like FSH by the anterior pituitary gland is ________. A) progesterone B) luteinizing hormone C) testosterone D) gonadotropin-releasing hormone E) estradiol

Hormone-based methods of birth control typically provide a continuous or cyclical dose of which hormone? A) progesterone B) luteinizing hormone C) follicle-stimulating hormone D) gonadotropin-releasing hormone E) testosterone

The birth control drug Mifepristone functions by ________. A) inhibiting release of gonadotropins from the pituitary B) blocking progesterone receptors in the uterus C) preventing release of the secondary oocyte from the ovary D) reducing sexual interest E) prolonging the endurance of the corpus luteum

Among these contraception methods, the highest risk of accidental pregnancy is associated with ________. A) the use of a diaphragm B) the use of a condom C) withdrawal D) an intrauterine device E) the rhythm method

The use of birth control pills (oral contraceptives) ________. A) reduces the incidence of ovulation B) prevents fertilization by keeping the sperm and egg physically separated by a mechanical barrier C) prevents implantation of an embryo D) prevents sperm from exiting the male urethra E) prevents oocytes from entering the uterus

Peaks of luteinizing hormone (LH) and follicle-stimulating hormone (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 end of the luteal phase of the ovarian cycle E) the secretory phase of the menstrual cycle

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) Estrous cycles are not controlled by hormones. E) Ovulation occurs before the endometrium thickens in estrous cycles.

During the menstrual cycle, ________ peaks first, ________ peak next, and finally ________ peaks. A) estradiol; luteinizing hormone (LH) and progesterone; follicle-stimulating hormone (FSH) B) progesterone; luteinizing hormone (LH) and follicle-stimulating hormone (FSH); estradiol C) estradiol; luteinizing hormone (LH) and follicle-stimulating hormone (FSH); progesterone D) estradiol; luteinizing hormone (LH) and follicle-stimulating hormone (FSH); testosterone E) testosterone; estradiol and follicle-stimulating hormone (FSH); progesterone

Testosterone is synthesized primarily ________. A) sperm cells B) neurons of the hypothalamus C) cells within the testes D) secretory cells of the anterior pituitary gland E) cells lining the seminiferous tubules

At the end of a nonpregnant human ovarian cycle, the breakdown and discharge of the lining of the uterus is called ________. A) menstruation B) lactation C) fertilization D) menopause E) ovulation

Which of the following is the most likely explanation for the lack of a filter blocking the passage of alcohol between the maternal and fetal circulations in humans? A) There has not been enough time to evolve such a barrier. B) Such a barrier would probably also block important molecules that need to be passed to the fetus. C) The maternal and fetal blood mix directly together in an area with many villi, so a barrier is impossible. D) Alcohol has some positive effects on the fetus, so evolution has resulted in an intermediate level of filtering that blocks all but the worst abuses of alcohol.

What embryo-produced hormone maintains progesterone and estrogen secretion by the corpus luteum through the first trimester of pregnancy? A) luteinizing hormone (LH) B) follicle-stimulating hormone (FSH) C) progesterone D) human chorionic gonadotropin (hCG) E) gonadotropin-releasing hormone (GnRH)

Labor contractions can be increased by the medical use of a synthetic drug that mimics the action of ________. A) testosterone B) luteinizing hormone C) oxytocin D) prolactin E) vasopressin

Which of the following contributes to the continued development and maintenance of the uterus during pregnancy? A) inhibin B) testosterone C) oxytocin D) prolactin E) progesterone

Imagine that a woman is in the final week of her pregnancy. Her doctor gives her an injection of oxytocin. The likely result of this is that the pregnant woman would ________. A) undergo the loss of oxytocin receptors from her uterine smooth muscle cells B) stop secreting prostaglandins from the placenta C) undergo vigorous contractions of her uterine muscles D) increase the synthesis and secretion of progesterone E) be prevented from lactation

During human gestation, rudiments of all organs develop ________. A) in the first trimester B) in the second trimester C) in the third trimester D) while the embryo is in the oviduct E) during the blastocyst stage

A pregnant woman past her due date comes into the hospital. The doctor decides it is time for the baby to be delivered. Before performing a cesarean section, the doctor wants to try to induce labor. Which of the following would she most likely inject? A) estrogen B) progesterone C) luteinizing hormone (LH) D) follicle-stimulating hormone (FSH) E) oxytocin

Which statement describes a difference in the development of marsupial versus eutherian (or placental) mammals? A) Marsupial young are ejected at the end of the estrous cycle, as the corpus luteum is not maintained. B) Marsupials undergo a longer gestation, hence the long time spent in the pouch. C) Only eutherians are born with well-formed jaws, gut, and forelimbs. D) Marsupials hatch from an egg, whereas eutherians are born.

In excreted urine, a reliable "marker" that a pregnancy has initiated is ________. A) progesterone B) estrogen C) follicle-stimulating hormone D) human chorionic gonadotropin (hCG) E) hypothalamic-releasing hormones

During pregnancy, mother's cardiovascular and pulmonary systems can change in which of the following ways? I. larger heart II. larger lungs III. faster heart beat IV. faster breathing V. increased blood volume A) only I and II B) only III and IV C) only I, III, and V D) only I, III, IV and V E) I, II, III, IV and V

Birth is complete once ________. A) the baby is born B) the placenta is delivered C) the baby begins to nurse D) oxytocin is released from the posterior pituitary gland

What two organs show particularly rapid growth and development in the last weeks of pregnancy? A) stomach and kidneys B) brain and heart C) lungs and brain D) kidneys and lungs E) eyes and ears

The amnion that contains the protective amniotic fluid is derived from what embryonic structure? A) inner cell mass B) trophoblast C) notochord D) somite E) blastocoel