Campbell’s Biology, 9e (Reece et al.)
Chapter 47 Animal Development
This chapter emphasizes the shared features of animal development, uniting diverse organisms and
diverse vocabulary in search of common understanding of milestones in development. It includes an
updated discussion of research findings in the field of evolutionary development, highlighting studies of
model organisms.
Multiple-Choice Questions
1) The structure of the Drosophila gene called Tinman is similar to a gene in humans that also
A) promotes ear development.
B) specifies the location of the heart.
C) determines structures in the eyes.
D) specifies limb elongation points.
E) filters lymphatic fluid.
2) As an embryo develops, new cells are produced as the result of
A) differentiation.
B) preformation.
C) cell division.
D) morphogenesis.
E) epigenesis.
3) Fertilization of an egg without activation is most like
A) placing the key in the ignition of a car but not starting the engine.
B) resting during halftime of a basketball game.
C) preparing a pie from scratch and baking it in the oven.
D) walking to the cafeteria and eating lunch.
E) dropping a rock off a cliff and watching it land in the valley below.
4) Contact of a sperm with signal molecules in the coat of an egg causes the sperm to undergo
A) mitosis.
B) depolarization.
C) apoptosis.
D) vitellogenesis.
E) the acrosomal reaction.
5) Even in the absence of sperm, metabolic activity in an egg can be artificially activated by
A) abnormally high levels of carbonic acid in the cytosol.
B) abnormally low levels of extracellular oxygen.
C) injection of calcium ions into the cytosol.
D) exposure to the low pH of the uterus.
E) depletion of its ATP supplies.
6) The formation of the fertilization membrane requires an increase in the availability of
A) bicarbonate ions.
B) calcium ions.
C) hydrogen ions.
D) potassium ions.
E) sodium ions.
7) A sea urchin zygote undergoes its first cell division
A) 5 seconds after fertilization.
B) 30 minutes after fertilization.
C) 90 minutes after fertilization.
D) 4 hours after fertilization.
E) 24 hours after fertilization.
8) A human zygote undergoes its first cell division
A) 5 seconds after fertilization.
B) 30 minutes after fertilization.
C) 90 minutes after fertilization.
D) 4 hours after fertilization.
E) 24 hours after fertilization.
9) A reproductive difference between sea urchins and humans is
A) the sea urchin egg completes meiosis prior to fertilization, but meiosis in humans is completed after
fertilization.
B) sea urchin eggs are produced by meiosis, but human eggs are produced by mitosis.
C) sea urchin eggs and sperm are of equal size, but human eggs are much bigger than human sperm.
D) sea urchins, but not humans, have a need to block polyspermy because only in sea urchins can there
be more than one source of sperm to fertilize the eggs.
E) sea urchin zygotes get their mitochondria from the sperm but human zygotes get their mitochondria
from the egg.
10) Contact of a sea urchin egg with signal molecules on sperm causes the egg to undergo a brief
A) mitosis.
B) membrane depolarization.
C) apoptosis.
D) vitellogenesis.
E) acrosomal reaction.
11) During fertilization, the acrosomal contents
A) block polyspermy.
B) help propel more sperm toward the egg.
C) digest the protective jelly coat on the surface of the egg.
D) nourish the mitochondria of the sperm.
E) trigger the completion of meiosis by the sperm.
12) The vitelline layer of the sea urchin egg
A) is outside of the fertilization membrane.
B) releases calcium, which initiates the cortical reaction.
C) has receptor molecules that are specific for binding acrosomal proteins.
D) is first visible only when organogenesis is nearly completed.
E) is a mesh of proteins crossing through the cytosol of the egg.
13) In a newly fertilized egg, the vitelline layer
A) opens the egg’s nuclear membrane to allow haploid sperm DNA to enter.
B) hardens to form a protective cover.
C) secretes hormones that enhance steroidogenesis by the ovary.
D) reduces the loss of water from the egg and prevents desiccation.
E) provides most of the nutrients used by the zygote.
14) From earliest to latest, the overall sequence of early development proceeds in which of the following
sequences?
A) first cell division → synthesis of embryo’s DNA begins → acrosomal reaction → cortical reaction
B) cortical reaction → synthesis of embryo’s DNA begins → acrosomal reaction → first cell division
C) cortical reaction → acrosomal reaction → first cell division → synthesis of embryo’s DNA begins
D) first cell division → synthesis of embryo’s DNA begins → acrosomal reaction → cortical reaction
E) acrosomal reaction → cortical reaction → synthesis of embryo’s DNA begins → first cell division
15) The cortical reaction functions directly in the
A) formation of a fertilization envelope.
B) production of a fast block to polyspermy.
C) release of hydrolytic enzymes from the sperm cell.
D) generation of a nerve-like impulse by the egg cell.
E) fusion of egg and sperm nuclei.
16) In sea urchins, the “fast block” and the longer lasting “slow block” to polyspermy, respectively, are
A) the acrosomal reaction and the formation of egg white.
B) the cortical reaction and the formation of yolk protein.
C) the jelly coat of the egg and the vitelline membrane.
D) membrane depolarization and the cortical reaction.
E) inactivation of the sperm acrosome.
17) In an egg cell treated with EDTA, a chemical that binds calcium and magnesium ions, the
A) acrosomal reaction would be blocked.
B) fusion of sperm and egg nuclei would be blocked.
C) fast block to polyspermy would not occur.
D) fertilization envelope would not be formed.
E) zygote would not contain maternal and paternal chromosomes.
18) In mammals, the nuclei resulting from the union of the sperm and the egg are first truly diploid at
the end of the
A) acrosomal reaction.
B) completion of spermatogenesis.
C) initial cleavage.
D) activation of the egg.
E) completion of gastrulation.
19) Fertilization normally
A) reinstates diploidy.
B) follows gastrulation.
C) is required for parthenogenesis.
D) merges two diploid cells into one haploid cell.
E) precedes ovulation.
20) In mammalian eggs, the receptors for sperm are found in the
A) fertilization membrane.
B) zona pellucida.
C) cytosol of the egg.
D) nucleus of the egg.
E) mitochondria of the egg.
21) Compared to sea urchin eggs, those of mammals
A) complete the fertilization process more rapidly.
B) have not already completed meiosis at the time of ovulation.
C) have a more distinct animal pole.
D) have a more distinct vegetal pole.
E) have no requirement for the cortical reaction.
22) A human blastomere is
A) an embryonic cell that is much smaller than the ovum.
B) an embryonic structure that includes a fluid-filled cavity.
C) that part of the acrosome that opens the egg’s membrane.
D) a component of the zona pellucida.
E) a cell that contains a (degenerating) second polar body.
23) At the moment of sperm penetration, human eggs
A) have used flagellar propulsion to move from the ovary to the oviduct.
B) accept as many sperm as possible in order to select the one with the highest fertility.
C) are still located within the ovary.
D) have a paper-thin cell of calcium carbonate that prevents desiccation.
E) are still surrounded by follicular cells.
24) In a developing frog embryo, most of the yolk is
A) located near the animal pole.
B) located near the vegetal pole.
C) found within the cleavage furrow.
D) found within the blastocoels.
E) distributed equally throughout the embryo.
25) Among these choices, the largest cell involved in frog reproduction is
A) the spermatozoon.
B) the ovum.
C) a blastomere in the vegetal pole.
D) a blastomere in the animal pole.
E) one of the products of the first cleavage.
26) The pattern of embryonic development in which only the cells lacking yolk subsequently undergo
cleavage is called
A) arcadian development, which is typical of insects.
B) holoblastic development, which is typical of marsupial mammals.
C) meroblastic development, which is typical of humans.
D) holoblastic development, which is typical of amphibians.
E) meroblastic development, which is typical of birds.
27) As cleavage continues during frog development, the size of the blastomeres
A) increases as the number of the blastomeres decreases.
B) increases as the number of the blastomeres increases.
C) decreases as the number of the blastomeres increases.
D) decreases as the number of the blastomeres decreases.
E) increases as the number of the blastomeres stays the same.
28) During the early part of the cleavage stage in frog development, the rapidly developing cells
A) skip the mitosis phase of the cell cycle.
B) skip the S phase of the cell cycle.
C) skip the G1 and G2 phases of the cell cycle.
D) rapidly increase the volume and mass of the embryo.
E) skip the cytokinesis phase of the cell cycle.
29) The vegetal pole of the zygote differs from the animal pole in that
A) the vegetal pole has a higher concentration of yolk.
B) the blastomeres originate only in the vegetal pole.
C) the posterior end of the embryo forms at the vegetal pole.
D) the vegetal pole cells undergo mitosis but not cytokinesis.
E) the polar bodies bud from this region.
30) The small portion of the embryo that will become its dorsal side develops from the
A) morula.
B) primitive streak.
C) archenteron.
D) gray crescent.
E) blastocoel.
31) The yolk of the frog egg
A) prevents gastrulation.
B) is concentrated at the animal pole.
C) is homogeneously arranged in the egg.
D) impedes the formation of a primitive streak.
E) supports the higher rate of cleavage at the animal pole compared to the vegetal pole.
32) An embryo with meroblastic cleavage, extraembryonic membranes, and a primitive streak must be
that of
A) an insect.
B) a fish.
C) an amphibian.
D) a bird.
E) a sea urchin.
33) Meroblastic cleavage occurs in
A) sea urchins, but not humans or birds.
B) humans, but not sea urchins or birds.
C) birds, but not sea urchins or humans.
D) both sea urchins and birds, but not humans.
E) both humans and birds, but not sea urchins.
34) Which of the following correctly displays the sequence of developmental milestones?
A) cleavage → blastula → gastrula → morula
B) cleavage → gastrula → morula → blastula
C) cleavage → morula → blastula → gastrula
D) gastrula → morula → blastula → cleavage
E) morula → cleavage → gastrula → blastula
35) 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.
36) 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.
37) 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 above the gray crescent in the animal pole.
38) The archenteron of the developing frog eventually develops into the
A) reproductive organs.
B) blastocoel.
C) heart and lungs.
D) digestive tract.
E) brain and spinal cord.
39) The vertebrate ectoderm is the origin of the
A) nervous system.
B) liver.
C) pancreas.
D) heart.
E) kidneys.
40) In frog embryos, the blastopore becomes the
A) anus.
B) ears.
C) eyes.
D) nose.
E) mouth.
41) In a frog embryo, gastrulation
A) produces a blastocoel displaced into the animal hemisphere.
B) occurs along the primitive streak in the animal hemisphere.
C) is impossible because of the large amount of yolk in the ovum.
D) proceeds by involution 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.
42) The earliest developmental stage among these choices is
A) germ layers.
B) morula.
C) blastopore.
D) gastrulation.
E) invagination.
43) Which of the following is a correct description of an anatomical relationship?
A) The mesoderm gives rise to the notochord.
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.
44) An open space within the gastrula is the
A) ectoderm.
B) mesoderm.
C) archenteron.
D) endoderm.
E) neural crest cells.
45) Although it contributes no cells to the embryo, the formation of the primitive streak is guided by the
structure known as the
A) endoderm.
B) mesoderm.
C) ectoderm.
D) neural crest.
E) hypoblast.
46) The primitive streak in a bird is the functional equivalent of
A) the lip of the blastopore in the frog.
B) the archenteron in a frog.
C) polar bodies in a sea urchin.
D) the notochord in a mammal.
E) neural crest cells in a mammal.
47) In all vertebrate animals, development requires
A) a large supply of yolk.
B) an aqueous environment.
C) extraembryonic membranes.
D) an amnion.
E) a primitive streak.
48) The least amount of yolk would be found in the egg of a
A) bird.
B) fish.
C) frog.
D) eutherian (placental) mammal.
E) reptile.
49) A primitive streak forms during the early embryonic development of
A) birds, but not frogs or humans.
B) frogs, but not birds or humans.
C) humans, but not birds or frogs.
D) birds and frogs, but not humans.
E) humans and birds, but not frogs.
50) Extraembryonic membranes develop in
A) mammals, but not birds or lizards.
B) birds, but not mammals or lizards.
C) lizards, but not mammals or birds.
D) mammals and birds, but not lizards.
E) mammals, birds, and lizards.