Mastering: Reproduction and Development

Ovulation usually occurs on or about day _____ of a 28-day ovarian cycle. 1 7 14 21 28

14 Ovulation usually occurs about halfway through the 28-day ovarian cycle.

Which of the following is not a potential advantage of asexual reproduction? It allows animals that are genetically well suited to a particular environment to quickly expand their populations. It produces genetically diverse populations. It saves the time and energy required to produce gametes. It allows animals that do not move around to produce offspring without finding mates.

It produces genetically diverse populations.

Which pituitary secretion stimulates the testes to secrete androgens? LH ACTH TSH PRL FSH

LH In males, luteinizing hormone (LH) stimulates the testes to secrete androgens.

A surge in which hormone(s) immediately precedes ovulation? LH only LH and FSH progesterone only FSH only

LH and FSH

A surge in estrogen levels correlates with a surge in progesterone levels. Supported Not supported Cannot be determined from the graph

Not supported

Which male reproductive structures are responsible for the transport and delivery of sperm? Seminal vesicles, vas deferens, and urethra Vas deferens, urethra, and penis Testis and epidydymis Seminal vesicles, prostate gland, and bulbourethral gland

Seminal vesicles, vas deferens, and urethra The vas deferens transports sperm from the epididymis to the ejaculatory duct, which empties into the urethra; the urethra carries sperm through the penis to the outside of the body and into the female reproductive tract.

Which of the following statements regarding sexual reproduction is true? Sexual reproduction allows animals to expand their populations faster than asexual reproduction. Sexual reproduction generates greater genetic variation than asexual reproduction. Sexual reproduction creates an individual that is a genetic copy of one parent. Populations of organisms that reproduce through sexual reproduction generally have more difficulty adapting to changing environments.

Sexual reproduction generates greater genetic variation than asexual reproduction.

Which of the following would be the most likely outcome if androgen receptors on cells in the hypothalamus and anterior pituitary suddenly could not bind androgen? FSH production would decrease. Sperm production would increase. Sperm production would decrease. HCG production would increase.

Sperm production would increase.

Which of the following statements about the reproductive system of human females is true? The corpus luteum secretes progesterone, which helps maintain the uterine lining during pregnancy. In human females, eggs develop within the uterus. The cervix is an important structure of sexual arousal. After nine months of development, an embryo is called a fetus.

The corpus luteum secretes progesterone, which helps maintain the uterine lining during pregnancy.

Which of the following statements about the male reproductive system is FALSE? The glans portion of the penis contributes to semen. The urethra in men, but not women, participates in reproduction and urine transport. The scrotum permits sperm to develop below the core body temperature. The testes have dual roles, producing gametes and hormones.

The glans portion of the penis contributes to semen. This is the FALSE statement. The glans is the head of the penis. It is highly sensitive and is surrounded by a foreskin at birth, which may be trimmed back during circumcision.

Which hormone(s) is(are) directly responsible for triggering the development of the secondary sex characteristics of males, such as beard growth? androgens thymosin epinephrine insulin parathyroid hormone

androgens Androgens, such as testosterone, are responsible for both sperm production and the secondary sex characteristics of males.

Reproductive systems with external fertilization are most common in terrestrial animals. animals that are widely dispersed. aquatic animals. populations with many more males than females.

aquatic animals.

is the creation of genetically identical offspring by a lone parent.

asexual reproduction

Coral reefs are made up of genetically identical coral polyps. New polyps develop as offshoots from the parental polyp. What type of reproduction do coral polyps use? fission sexual reproduction budding fragmentation

budding

is the splitting off of new individuals from outgrowths of existing ones.

budding

Menstruation is triggered by HCG. coincides with the beginning of the pre-ovulatory phase of the ovarian cycle. is triggered by an LH surge. is triggered by an increase in the levels of estrogen and progesterone.

coincides with the beginning of the pre-ovulatory phase of the ovarian cycle.

What is the source of the hormones that, when suddenly absent, are directly responsible for the onset of menstruation? hypothalamus pituitary corpus luteum ovarian follicle

corpus luteum The corpus luteum produces both estrogen and progesterone; it disintegrates if pregnancy does not occur, and the sudden absence of these hormones triggers menstruation.

After being produced in the testes, sperm mature further in a structure called the prostate. vas deferens. seminal vesicle. epididymis.

epididymis

Sperm become capable of movement while in the _____. seminiferous tubules vas deferens ejaculatory ducts urethra epididymis

epididymis Sperm mature and become motile while in the epididymis

Based on the graph, elevated levels of which hormone(s) most likely stimulate the LH/FSH surge just before ovulation? progesterone testosterone estrogen progesterone and estrogen

estrogen

If there is no fertilization, degeneration of the corpus luteum results in a drop in _____, which results in the sloughing off of the uterus's endometrium. FSH estrogen and progesterone hypothalamic secretion of releasing hormones HCG LH

estrogen and progesterone Estrogen and progesterone are responsible for maintaining the endometrium in the event that the egg has been fertilized.

After ovulation, high levels of _____ inhibit _____ secretion. estrogen and progesterone ... FSH and LH FSH and LH ... estrogen and progesterone HCG ... estrogen and progesterone estrogen ... FSH androgens ... FSH and LH

estrogen and progesterone ... FSH and LH By secreting estrogen and progesterone, the corpus luteum maintains the endometrium and inhibits FSH and LH secretion.

Developing ovarian follicles primarily secrete _____. progesterone estrogens luteinizing hormone follicle-stimulating hormone human chorionic gonadotropin

estrogens Developing ovarian follicles secrete estrogen.

is the fusion of two haploid sex cells (sperm and egg) to form a diploid cell.

fertilization

If FSH were produced in smaller quantities than that produced in normal males, the prostate gland would secrete less fluid to nourish sperm fewer sperm would be formed this would inhibit the secretion of FSH by the anterior pituitary there would be less LH produced and therefore less androgen

fewer sperm would be formed FSH increases sperm production.

is a haploid sex cell (a sperm in males and an egg in females).

gamete

If there is fertilization, secretion of _____ by the early embryo maintains the corpus luteum. progesterone estrogen luteinizing hormone follicle-stimulating hormone human chorionic gonadotropin

human chorionic gonadotropin HCG, secreted by the early embryo, maintains the corpus luteum. The corpus luteum secretes estrogen and progesterone, which maintain the endometrium for implantation.

Which reproductive method is used most frequently by mammals? fragmentation external fertilization internal fertilization regeneration

internal fertilization In mammals the sperm are deposited within the female's body, and the resulting zygote develops into a fetus and is later born of the mother.

A rapid increase in the _____ level stimulates ovulation. progesterone estrogen luteinizing hormone follicle-stimulating hormone human chorionic gonadotropin

luteinizing hormone A surge in LH levels is responsible for triggering ovulation.

The hormone that initiates the development of specialized cells in the ovaries of women and triggers androgen production by the testes of men is _____. estrogen follicle-stimulating hormone (FSH) luteinizing hormone (LH) progesterone

luteinizing hormone (LH) Following ovulation, LH stimulates the transformation of the follicular tissue in the ovary to form the corpus luteum. In males, LH stimulates the Leydig cells to produce androgen.

Compared to animals that have separate sexes, an animal that is a hermaphrodite has the advantage of _____. producing offspring with greater genetic variability being able to reproduce during times of stability or stress mating with any other member of its species using less energy to produce gametes

mating with any other member of its species Organisms with separate sexes reproduce with members of the opposite sex. But hermaphrodites can mate with any other member of the species.

The secretion of androgens is regulated by a _____ feedback mechanism involving the _____ and _____. positive ... hypothalamus ... pituitary gland negative ... hypothalamus ... pituitary gland positive ... thyroid ... pituitary gland negative ... pancreas ... pituitary gland negative ... seminal vesicles ... prostate gland

negative ... hypothalamus ... pituitary gland An increase in androgens inhibits the secretion of releasing hormones by the hypothalamus and LH secretion by the pituitary gland. A decrease in androgens stimulates the secretion of releasing hormones by the hypothalamus and LH secretion by the pituitary gland.

On its way to fertilize a human egg, a sperm cell does not have to pass through which of the following? oviduct ovary vagina cervix

ovary The ovary is the source of the mature oocytes. After ovulation, the oocyte enters the oviduct, where fertilization occurs.

What is the usual site of the fertilization of an egg cell? uterus ovary oviduct abdominal cavity vagina

oviduct The oviducts are the usual sites of fertilization.

Into which structure is a human oocyte released upon ovulation? ovary uterus corpus luteum oviduct, after which it moves toward the uterus

oviduct, after which it moves toward the uterus It must first cross through a tiny space at the opening of the oviduct.

In the course of normal events leading to fertilization and eventually birth, the route of the egg, embryo, and finally fetus is from the ovary into the __________. uterus, to the oviduct, and then out the vagina urethra, to the labia, to the uterus, and then out the vagina oviduct, to the uterus, and then out the vagina oviduct, to the bladder, and then out the urethra

oviduct, to the uterus, and then out the vagina This is the route each would take.

Sperm develop in the _____. prostate gland bulbourethral glands seminiferous tubules hypothalamus seminal vesicles

seminiferous tubules Sperm develop in seminiferous tubules, found within testes.

is the creation of genetically unique offspring by two parents.

sexual reproduction

Asexual reproduction involves _____. integration of genetic information from two individuals a haploid phase of reproduction the union of two gametes the creation of genetically identical offspring by a lone parent

the creation of genetically identical offspring by a lone parent Asexual reproduction is reproduction without sex.

The route that sperm take from formation to ejaculation from the penis is from the testes to __________. the vas deferens, epididymis, ejaculatory duct, and urethra the urethra, epididymis, ejaculatory duct, and vas deferens the epididymis, vas deferens, ejaculatory duct, and urethra the vas deferens, ejaculatory duct, epididymis, and urethra

the epididymis, vas deferens, ejaculatory duct, and urethra The epididymis stores sperm while they continue to develop. Sperm leave the epididymis through the vas deferens, which joins with the seminal vesicle and forms the ejaculatory duct. The union of ejaculatory ducts from each testis forms the urethra.

What is shed from the body in menstruation? excess immature egg cells the thickened endometrium; its removal allows for implantation of a fertilized egg unsuccessful zygotes or early embryos the thickened endometrium when fertilization has not occurred

the thickened endometrium when fertilization has not occurred

The ovaries release increasing levels of estrogen and progesterone immediately after ovulation. This results in _____. menstruation and increased FSH and LH production thickening of the endometrium and reduced production of FSH and LH, which feeds back to prevent further ovulation maturation of additional egg cells formation of a zygote

thickening of the endometrium and reduced production of FSH and LH, which feeds back to prevent further ovulation

Sperm exit a male's body via the _____. ejaculatory duct urethra oviduct ureter epididymis

urethra The urethra carries both sperm and urine out of a male's body.

A fertilized egg usually implants itself and develops in the _____. uterus ovary oviduct abdominal cavity none of these

uterus The uterus is the usual site of the implantation and development of the fertilized egg.

is a fertilized egg (the diploid cell created by the fusion of sperm and egg).

zygote

How do ovulated oocytes get into the uterus? The oocyte actively swims through the oviduct, using its flagellum. Cilia within an oviduct create currents that sweep the egg toward the uterus. Because ovaries are within the uterus, the ovulated egg is already within the uterus. Fimbriae sweep over the oviduct.

Cilia within an oviduct create currents that sweep the egg toward the uterus. The oviduct has a funnel-like opening, and cilia on the inner epithelium lining the duct create currents that sweep the egg toward the uterus.

Which of the following events does NOT occur during human fertilization? Acrosomal enzymes break down the zona pellucida. Enzymes on the outside of the sperm break down the follicle cells surrounding the egg The DNA of the sperm unites with the DNA of the egg. Receptors on the sperm bind to the zona pellucida surrounding the egg.

Enzymes on the outside of the sperm break down the follicle cells surrounding the egg There are no enzymes on the outside of the sperm; the sperm move through the follicle cells to gain access to the zona pellucida.

Which pituitary secretion stimulates sperm production? LH ACTH TSH PRL FSH

FSH In males, follicle-stimulating hormone (FSH) stimulates sperm production.

The anterior pituitary gland, under the control of the hypothalamus, produces _____, which stimulate _____. estrogen and progesterone ... thickening of the endometrium FSH and LH ... thickening of the endometrium estrogen and progesterone ... egg maturation and ovulation FSH and LH ... egg maturation and ovulation

FSH and LH ... egg maturation and ovulation

True or false. During sperm maturation, secondary spermatocytes are the products of meiosis II that go on to form spermatids, which undergo restructuring to form spermatozoa. True False

False During sperm maturation, diploid parent cells produce primary spermatocytes, which undergo meiosis I to form secondary spermatocytes. Secondary spermatocytes undergo meiosis II to form spermatids, which undergo restructuring to form spermatozoa.

Which of the following is a disadvantage of asexual reproduction? It is faster than sexual reproduction. An animal can reproduce without finding mates. It does not increase genetic variability. It uses less energy than sexual reproduction.

It does not increase genetic variability. This is an advantage that sexual reproduction has over asexual reproduction.

What is the function of the thickened endometrium? It nourishes the early embryo during the process of implantation. It prevents unfertilized eggs from implanting in the wall of the uterus. It facilitates fertilization of the egg by nourishing sperm cells. It stimulates the follicles to mature an egg cell.

It nourishes the early embryo during the process of implantation.

Which of the following statements about the female reproductive system is FALSE? The endometrium, richly supplied with blood vessels, is where the young embryo implants. When people speak of the "womb," they are referring to the uterus. The labia majora is a thin piece of tissue that partially covers the opening of the vagina. An ectopic pregnancy occurs when an embryo implants outside of the uterus.

The labia majora is a thin piece of tissue that partially covers the opening of the vagina. The labia minora, not majora, is a thin piece of tissue that partially covers the opening of the vagina.

How are the ovulation cycle and the menstruation cycle coordinated? A single gland releases a pair of hormones that control both processes. Each cycle is independent of the other; the cycles frequently drift out of phase with each other, resulting in infertility. The processes regulate each other through a system that involves four major hormones. The anterior pituitary gland releases one of four different hormones to stimulate each phase of the overall coordinated cycle.

The processes regulate each other through a system that involves four major hormones.

What prevents menstruation when a woman first becomes pregnant? The corpus luteum releases HCG. The pituitary gland increases its secretion of LH and FSH. The developing placenta of the embryo presses against blood vessels of the endometrium, preventing the fluid from escaping. The release of HCG from the implanted embryo acts like LH, stimulating the corpus luteum to continue to secrete progesterone and estrogen.

The release of HCG from the implanted embryo acts like LH, stimulating the corpus luteum to continue to secrete progesterone and estrogen. Human chorionic gonadotropin (HCG) is typically the substance tested for in pregnancy tests.

The onset of menstruation is triggered by __________. a sudden increase in the levels of progesterone and FSH a drop in the levels of FSH and LH a drop in the levels of progesterone and estrogen a drop in the level of estrogen

a drop in the levels of progesterone and estrogen If implantation of an embryo does not occur within a few days, the corpus luteum stops secreting progesterone and estrogen. This leads to disintegration of the endometrium.