Chapter 47

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.

(A) The mesoderm gives rise to the skeletal system.

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.

(D) The density of Daphnia populations could be easily manipulated in the laboratory.

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.

(A) Daphnia males are produced asexually from unfertilized eggs.

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.

(A) Spermatogenesis results in four mature sperm cells, whereas oogenesis results in one mature egg cell.

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

(A) anus

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

(A) both have the same number of chromosomes

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

(A) mitosis

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

(A) mitosis

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

(A) nervous system

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

(A) one secondary oocyte

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

(A) produce single-celled zygotes

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

(A) vitelline envelope

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.

(B) Only half of the offspring from sexually reproducing females are also females.

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.

(B) Testes of species 2 are larger than testes of species 1.

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

(B) can produce diverse phenotypes that may enhance survival of a population in a changing environment

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

(B) embryonic germ layers would not form

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

(B) fallopian tube

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

(B) increases; decreases

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

(B) neural tube

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.

(B) when conditions for survival are unfavorable

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.

(C) A human oocyte completes meiosis after a sperm penetrates it.

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.

(C) Offspring are nourished via the egg's yolk prior to live birth.

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

(C) blastocoel

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

(C) body axes

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

(C) cleavage → gastrulation → organogenesis

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

(C) cleavage, formation of a blastula, gastrulation, and then organogenesis

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

(C) ectoderm → mesoderm → endoderm

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

(C) enables the species to flourish in stable habitats that are favorable to that species

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

(C) meiotic divisions required to produce each gamete

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

(C) nervous tissue

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

(C) parthenogenesis

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

(C) periods of temperature or food stresses on adults

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

(C) shallow lake

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

(C) testes

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

(C) the division of cytoplasm is unequal in oogenesis, whereas it is equal in spermatogenesis

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

(C) the second male's sperm fertilizes most of the eggs

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.

(D) An egg develops without being fertilized.

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.

(D) The gametes must be kept wet to avoid desiccation.

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

(D) cleavage → blastula → gastrula

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

(D) fertilization in Daphnia

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

(D) parthenogenesis

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

(D) proceeds as cells roll over the lip of the blastopore

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

(D) the formation of specialized adult tissues

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

(D) three germ layers form

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

(D) two or three small cells and one large cell that develops further if fertilized

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

(E) a species is in stable and favorable environments

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

(E) gastrulation

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

(E) gastrulation

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

(E) meiosis → gametes → zygote → mitosis → embryo

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

(E) the acrosome reaction