44. Animal Reproduction

In general, what is the ploidy (n) state of human cells?

Which of the following statements about parthenogenesis is correct?

A hermaphrodite is an animal that __________.

Which of the following is not a form of asexual reproduction?

Which reproductive method is universal among mammals?

In which of the following pairs are the terms mismatched?

Individuals clustered in the same area that release their gametes into the water at the same time are engaging in which of the following?

Some insect females are able to store sperm in __________ until environmental conditions are favorable for the development of their offspring.

An ovarian follicle undergoes several changes during the human female's menstrual cycle. Which of the following sequences is correct, beginning with the oocyte?

Immediately after ovulation into the coelom, an egg is collected into the __________.

How do egg cells enter the oviduct after ovulation?

Vestibular glands __________.

Where do developing sperm cells undergo meiosis?

The __________ is/are the site of testosterone production in the testis.

What is the final stage of labor?

A vasectomy is an effective technique for birth control in males because it __________.

If a woman wants to become pregnant, what is the optimal day on which to have sexual intercourse?

Pregnancy tests detect a hormone in a woman's urine that is present only when an embryo is developing in her uterus. This hormone is secreted by __________.

Through which of the following does a human sperm cell not have to pass in order to fertilize an egg?

A large number of hormones function in the human menstrual cycle, but only two of them are called female sex hormones. These are __________.

What is the source of the hormones that, when suddenly absent, are directly responsible for the onset of menstruation?

After the menstrual period, which of the following hormones is the first to increase significantly every 28 days or so, initiating the ovarian cycle?

Concentrations of which hormone stimulate the hypothalamus to increase or decrease hormones that stimulate sperm production in the testes?

After ovulation occurs, the empty follicle __________.

In many mammals, the testes are located outside the abdominal cavity within the scrotum because __________.

Which part of the male reproductive tract stores sperm as they mature?

Which structure is part of the excretory and reproductive systems in males?

Sperm cells have several components; the function of the acrosome is to __________.

Which part of the human sperm carries a haploid set of chromosomes?

In mammals, meiosis to produce the female egg cell is initiated in the __________.

From a single primary oocyte, oogenesis in a mammal will produce __________.

In spermatogenesis, each primary spermatocyte gives rise to __________sperm.

At what point does the secondary oocyte complete meiosis?

Which of the following statements about luteinizing hormone (LH) in the female reproductive system is correct?

Compared to polar bodies, the amount of cytoplasm found in an animal egg cell is __________.

Which of the following choices correctly lists the four phases of the sexual response cycle in their proper sequence?

In males, FSH __________.

Which of the following statements about oogenesis and spermatogenesis is correct?

Menstruation results in the discharge of __________.

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.

This graph plots the rise and fall of pituitary and ovarian hormones during the human ovarian cycle. Identify each hormone (A–D) and the reproductive events with which each one is associated (P–S). For A–D, choose from estrogen, LH, FSH, and progesterone. For P–S, choose from ovulation, growth of follicle, menstruation, and development of corpus luteum. How would the right-hand side of this graph be altered if pregnancy occurred? What other hormone is responsible for triggering this change?

What term describes the mode of asexual reproduction in which offspring develop from unfertilized eggs? a. parthenogenesis b. budding c. regeneration d. fission

In male mammals, excretory and reproductive systems share a. the vas deferens. b. the urethra. c. the seminal vesicle. d. the prostate.

Match each function with the correct structure. 2. Turns into the corpus luteum 3. Female gonad 4. Site of spermatogenesis 5. Site of fertilization in humans 6. Site of human gestation 7. Sperm duct 8. Secretes seminal fluid 9. Lining of uterus a. vas deferens b. prostate gland c. endometrium d. testis e. follicle f. uterus g. ovary h. oviduct

In sperm competition, what is 'second-male advantage'? a. the observation that when females mate with two males, each male fertilizes the same number of eggs b. the observation that when females mate with two males, the second male fertilizes most of the eggs c. the observation that females routinely mate with at least two males before laying eggs or becoming pregnant d. the observation that accessory fluids prevent matings by second males—for example, by forming copulatory plugs

Add labels to the figure that follows, which illustrates female internal reproductive organs.

What happens to the egg cell and the remains of the tissue it developed in at ovulation?

Which of the following is not properly paired? a. seminiferous tubule—cervix b. vas deferens—oviduct c. testosterone—estradiol d. scrotum—labia majora

Which of the following statements regarding animal development is/are correct? Select True or False for each statement. T/F The neural tube forms after organogenesis is complete T/F The blastocyst is formed during cleavage T/F During cleavage, the zygote divides rapidly without growth, forming a mass of cells T/F Animals have two germ layers

Which of the following is properly paired? (A)seminiferous tubule—cervix (B)vas deferens—oviduct (C)corpus luteum—Sertoli cell (D)scrotum—clitoris

A sperm cell follows which path? a. seminiferous tubules, epididymis, vas deferens, urethra; b. urethra, vas deferens, seminiferous tubules, epididymis; c. seminiferous tubules, vas deferens, epididymis, urethra; d. epididymis, seminiferous tubules, vas deferens, urethra; e. epididymis, vas deferens, seminiferous tubules, urethra

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.

True or false: The corpus luteum is retained upon implantation due to the presence of the hormone human chorionic gonadotropin (hCG).

An egg cell that is not fertilized follows which path? a. ovary, oviduct, uterus, cervix; b. ovary, uterus, oviduct, cervix; c. oviduct, ovary, cervix, uterus; d. oviduct, ovary, uterus, cervix; e. ovary, oviduct, cervix, uterus

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.

Summarize the experimental evidence that Daphnia require three cues to trigger sexual reproduction. Discuss what these cues indicate about the environment.

Which of the following is mismatched? a. urethra: sperm passage; b. testes: hormone production; c. vas deferens: semen production; d. seminiferous tubules: sperm production

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.

Many frogs and mice are similar in size, yet a frog egg is vastly larger than a mouse egg. Propose a plausible explanation for this difference in the egg size.

The production of gametes                   . a. begins at puberty in males and females; b. requires that the testes of males produce semen; c. results in the production of diploid cells from haploid cells; d. begins at puberty in females; e. produces sperm and eggs that carry half the number of chromosomes as nongametes

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

How do spermatogenesis and oogenesis in humans differ with respect to numbers of cells produced, gamete size, and timing of the second meiotic division?

Which statement about human reproduction is true? (A)Fertilization occurs in the vagina. (B)Spermatogenesis and oogenesis both require normal body temperature. (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.

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.

Give examples of negative and positive feedback in hormonal control of the human menstrual cycle. Why can a high estradiol level be considered a 'readiness' signal from a follicle?

Propose an experiment to test the hypothesis that cells from only one region of a frog blastula form the ectoderm. What results from this experiment would support this hypothesis?

After a sperm penetrates an egg, it is important that the vitelline layer separate from the egg so that it can a. secrete important hormones. b. enable the fertilized egg to implant in the uterus. c. prevent more than one sperm from entering the egg. d. attract additional sperm to the egg.

The BMI z-score is a relative measure of body mass index (BMI) that takes into account age. Higher values represent heavier individuals for a given height. The table here shows the BMI z-score of pre- and post-pubertal girls at three ages. Which of the following conclusions can you draw from the data? a. At a given age, there are more girls with low BMI z-scores than with high BMI z-scores. b. At a given age, girls with high BMI z-scores are more likely to have begun puberty than girls with low BMI z-scores. c. Girls 11, 12, and 13 years of age are equally likely to have begun puberty. d. There is no relationship between BMI z-score and age of beginning puberty.

In the 1960s, the U.S. Food and Drug Administration approved a contraceptive that allowed women to plan desired pregnancies and prevent unwanted pregnancies. Oral hormonal contraception ('the pill') uses synthetic hormones similar in structure to progesterone and/or estradiol. What is the pill's mechanism of action? Which of the following is the most effective form of contraception? a. condom b. diaphragm c. withdrawal d. the pill

How does a zygote differ from a mature egg? a. A zygote has more chromosomes. b. A zygote is smaller. c. A zygote consists of more than one cell. d. A zygote divides by meiosis.

In the 1960s, the U.S. Food and Drug Administration approved a contraceptive that allowed women to plan desired pregnancies and prevent unwanted pregnancies. Oral hormonal contraception ('the pill') uses synthetic hormones similar in structure to progesterone and/or estradiol. What is the pill's mechanism of action? Use your knowledge of the hormonal regulation of reproduction to predict the effect of a daily synthetic progesterone pill on (a) pituitary secretion of LH and FSH, and (b) ovarian secretion of estradiol and progesterone.

A woman had several miscarriages. Her doctor suspected that a hormonal insufficiency was causing the lining of the uterus to break down, as it does during menstruation, terminating her pregnancies. Treatment with which of the following might help her remain pregnant? a. oxytocin b. follicle-stimulating hormone c. luteinizing hormone d. prolactin

In the 1960s, the U.S. Food and Drug Administration approved a contraceptive that allowed women to plan desired pregnancies and prevent unwanted pregnancies. Oral hormonal contraception ('the pill') uses synthetic hormones similar in structure to progesterone and/or estradiol. What is the pill's mechanism of action? Scientists confirmed the pill's mechanism of action by measuring plasma hormone levels in women before and after they went on the pill (* means P<0.05, ** means P<0.01, and *** means P<0.001). Do the data shown here support the hypothesis that the pill affects hormonal signaling?

The embryos of reptiles (including birds) and mammals have systems of extraembryonic membranes. What are the functions of these membranes, and how do fish and frog embryos survive without them?

In the 1960s, the U.S. Food and Drug Administration approved a contraceptive that allowed women to plan desired pregnancies and prevent unwanted pregnancies. Oral hormonal contraception ('the pill') uses synthetic hormones similar in structure to progesterone and/or estradiol. What is the pill's mechanism of action? Use the information in the graph to explain how the pill affects each of the following: (a) maturation of a follicle, (b) thickening of the uterine lining during the follicular phase, (c) probability of ovulation, and (d) volume of menstrual fluid.

Compare sperm formation with egg formation. In what ways are the processes similar? In what ways are they different?

In the 1960s, the U.S. Food and Drug Administration approved a contraceptive that allowed women to plan desired pregnancies and prevent unwanted pregnancies. Oral hormonal contraception ('the pill') uses synthetic hormones similar in structure to progesterone and/or estradiol. What is the pill's mechanism of action? Use Table 47.2 to compare and contrast the mechanisms of action of emergency contraception and mifepristone to that of the pill. Which methods act as contraception and which act to terminate a pregnancy? Explain.

In the 1960s, the U.S. Food and Drug Administration approved a contraceptive that allowed women to plan desired pregnancies and prevent unwanted pregnancies. Oral hormonal contraception ('the pill') uses synthetic hormones similar in structure to progesterone and/or estradiol. What is the pill's mechanism of action? Imagine that four different contraceptives are under development. One blocks ovulation, one blocks fertilization, one blocks cleavage, and one blocks implantation. In the United States, which contraceptive is likely to be the least controversial to bring to market? Why?