1. Which of the following characteristics is unique to all members of the animal
kingdom?
a. Sexual reproduction
b. Multicellular
c. Lack of cell walls
d. Heterotrophic
The correct answer is c—
A. Answer a is incorrect. Sexual reproduction is present in the plants, fungi, and
some protists.
The correct answer is c—
B. Answer b is incorrect. Both fungi and plants are multicellular.
The correct answer is c—Lack of cell walls
C. Answer c is correct. Cell walls are present in plants, fungi, and some protists, but
are lacking in all animals.
The correct answer is c—
D. Answer d is incorrect. Fungi and some protists are heterotrophic.
2. Animals are unique in the fact that they possess _____ for movement and ____
for conducting signals between cells.
a. brains; muscles
b. muscle tissue; nervous tissue
c. limbs; spinal cords
d. flagella; nerves
The correct answer is b—
A. Answer a is incorrect. Not all animals have brains and muscles.
The correct answer is b—muscle tissue; nervous tissue
B. Answer b is correct. These two tissue types are unique to animals.
The correct answer is b—
C. Answer c is incorrect. Not all animals have limbs and spinal cords.
The correct answer is b—
D. Answer d is incorrect. Not all animals have flagella and nerves.
3. In animal sexual reproduction the gametes are formed by the process of
_________.
a. meiosis
b. mitosis
c. fusion
d. binary fission
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The correct answer is a—meiosis
A. Answer a is correct.
The correct answer is a—
B. Answer b is incorrect. In animals, mitosis is used to increase cell number.
The correct answer is a—
C. Answer c is incorrect. In animals, eggs and sperm fuse to form a zygote.
The correct answer is a—
D. Answer d is incorrect. This is the form of cell division common in bacteria.
4. The evolution of bilateral symmetry was a necessary precursor for the evolution
of __________.
a. tissues
b. segmentation
c. a body cavity
d. cephalization
The correct answer is d—
A. Answer a is incorrect. Tissues evolved prior to bilateral symmetry.
The correct answer is d—
B. Answer b is incorrect. Bilateral symmetry is not a necessary precursor for
segmentation.
The correct answer is d—
C. Answer c is incorrect. Bilateral symmetry is not a necessary precursor for the
evolution of a body cavity.
The correct answer is d—cephalization
D. Answer d is correct. Cephalization is the formation of a head, which requires
bilateral symmetry.
5. A fluid-filled cavity that develops completely within the mesoderm is a
characteristic of a _________.
a. coelomate
b. pseudocoelomate
c. acoelomate
d. all of the above
The correct answer is a—coelomate
A. Answer a is correct. This distinguishes the body cavity of a coelomate from the
other forms of body cavities.
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The correct answer is a—
B. Answer b is incorrect. In a pseudocoelomate the body cavity forms between the
endoderm and mesoderm.
The correct answer is a—
C. Answer c is incorrect. An acoelomate lacks a body cavity.
The correct answer is a—
D. Answer d is incorrect.
6. The following diagram is of the blastopore stage of embryonic development.
Based on the information in the diagram, which of the following statements is
correct?
a. It is a diagram of a protostome.
b. It would have formed by radial cleavage.
c. It would exhibit determinate development.
d. All of the above are correct.
The correct answer is d—
A. Answer a is incorrect. This is a diagram of a protostome, but it is not the only
correct statement.
The correct answer is d—
B. Answer b is incorrect. This diagram is produced by radial cleavage, but it is not
the only correct statement.
The correct answer is d—
C. Answer c is incorrect. This diagram does exhibit determinate development, but it
is not the only correct statement.
The correct answer is d—All of the above are correct.
D. Answer d is correct.
7. Which of the following statements is NOT true regarding segmentation?
a. Segmentation allows the evolution of redundant systems.
b. Segmentation is a requirement for a closed circulatory system.
c. Segmentation enhances locomotion.
d. Segmentation represents an example of convergent evolution.
The correct answer is b—
A. Answer a is incorrect. This statement is true.
The correct answer is b—Segmentation is a requirement for a closed circulatory system.
B. Answer b is correct. While many segmented organisms possess a closed
circulatory system, segmentation is not a requirement for this form of circulation.
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The correct answer is b—
C. Answer c is incorrect. This statement is true.
The correct answer is b—
D. Answer d is incorrect. This statement is true.
8. Which of the following characteristics is used to distinguish between a Parazoan
and a Eumetazoan?
a. Presence of a true coelom
b. Segmentation
c. Cephalization
d. Tissues
The correct answer is d—
A. Answer a is incorrect. Not all Eumetazoans have a true coelom.
The correct answer is d—
B. Answer b is incorrect. Not all Eumetazoans possess cephalization.
The correct answer is d—
C. Answer c is incorrect. Symmetry does not distinguish these groups.
The correct answer is d—Tissues
D. Answer d is correct. Parazoans lack tissues and organs.
9. With regards to classification in the animals, the study of which of the following
is significantly changing the organization of the kingdom?
a. Molecular systematics
b. Origin of tissues
c. Patterns of segmentation
d. Evolution of morphological characteristics
The correct answer is a—Molecular systematics
A. Answer a is correct. Advances in molecular systematics are reshaping the way
that scientists view the animal kingdom.
The correct answer is a—
B. Answer b is incorrect. Although still an important aspect of animal classification,
it is not responsible for recent changes.
The correct answer is a—
C. Answer c is incorrect. Although still an important aspect of animal classification,
it is not responsible for recent changes.
The correct answer is a—
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D. Answer d is incorrect. Although still an important aspect of animal classification,
it is not responsible for recent changes.
10. Which of the following characteristics would NOT apply to a species in the
Ecdysozoa?
a. Bilateral
b. Deuterostome
c. Molt cuticles at least once in their life cycle
d. Metazoan
The correct answer is b—
A. Answer a is incorrect. Refer to Figure 32.5.
The correct answer is b—Deuterostome
B. Answer b is correct. Members of the Ecdysozoa are protostomes.
The correct answer is b—
C. Answer c is incorrect. Refer to Figure 32.5.
The correct answer is b—
D. Answer d is incorrect. Refer to Figure 32.5.
11. The most recent phylum to be added to the animal kingdom is the ____________.
a. Bryozoa
b. Annelida
c. Micrognathoza
d. Loricifera
The correct answer is c—
A. Answer a is incorrect. Refer to Table 32.2.
The correct answer is c—
B. Answer b is incorrect. Refer to Table 32.2.
The correct answer is c—Micrognathoza
C. Answer c is correct. The first Micrognathoza were discovered in 2000.
The correct answer is c—
D. Answer d is incorrect. Although a recent addition, this phylum is not the latest.
Refer to Table 32.2.
12. The _______ contain the greatest number of known species.
a. Chordata
b. Arthropoda
c. Porifera
d. Mollusca
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The correct answer is b—
A. Answer a is incorrect. Refer to Table 32.2.
The correct answer is b—Arthropoda
B. Answer b is correct. There are over 1 million known species of arthropods.
The correct answer is b—
C. Answer c is incorrect. Refer to Table 32.2.
The correct answer is b—
D. Answer d is incorrect. Mollusca represent the second-largest phylum.
13. Which hypothesis for the evolution of the Metazoa suggests that they evolved
from organisms similar to modern ciliates?
a. Polyphyletic origin hypothesis
b. Multinucleate hypothesis
c. Colonial flagellate hypothesis
d. None of the above
The correct answer is b—
A. Answer a is incorrect. Review the description of these hypotheses in section 32.5.
The correct answer is b—Multinucleate hypothesis
B. Answer b is correct.
The correct answer is b—
C. Answer c is incorrect. Review the description of these hypotheses in section 32.5.
The correct answer is b—
D. Answer d is incorrect. Review the description of these hypotheses in section 32.5.
14. The evolution of which of the following occurs after the Cambrian explosion?
a. Cephalization
b. True coelom
c. Segmentation
d. None of the above
The correct answer is d—
A. Answer a is incorrect. There have been no new innovations in animal body plans
since the Cambrian explosion.
The correct answer is d—
B. Answer b is incorrect. There have been no new innovations in animal body plans
since the Cambrian explosion.
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The correct answer is d—
C. Answer c is incorrect. There have been no new innovations in animal body plans
since the Cambrian explosion.
The correct answer is d—None of the above
D. Answer d is correct. There have been no new innovations in animal body plans
since the Cambrian explosion.
15. A coelomate organism may have which of the following characteristics?
a. A circulatory system
b. Internal skeleton
c. Larger size than a pseudocoelomate
d. All of the above
The correct answer is d—
A. Answer a is incorrect. Although circulatory systems are characteristic of many
coelomates, this is not the only correct answer.
The correct answer is d—
B. Answer b is incorrect. Although an internal skeleton is a characteristic of many
coelomates, this is not the only correct answer.
The correct answer is d—
C. Answer c is incorrect. Although a larger size is a characteristic of many
coelomates, this is not the only correct answer.
The correct answer is d—All of the above
D. Answer d is correct.
Challenge Questions
1. Worm evolution represents an excellent means of understanding the evolution of
a body cavity. Using only the following phyla of worms (nematodes, annelids,
platyhelminthes, nemetera, hemichordates), construct a phylogenetic tree that is
only based on the form of body cavity (Refer to Figure 32.2 and Table 32.2 for
assistance). How does this relate to the material in Figure 32.5? Should body
cavity be used as the sole characteristic for classifying a worm?
Answer—The tree should contain platyhelminthes and nemetera on one branch, a second
branch should contain nematodes, and a third branch should contain the annelids and the
hemichordates. This does not coincide with the information in Figure 32.5. Therefore,
some of the different types of body cavities have evolved multiple times, and the body
cavities are not good characteristics to infer phylogenetic relationships.
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2. Most students find it hard to believe that the echinoderms and chordates are
closely related phyla. If it were not for their method of forming a body cavity,
where would you place the Echinodermata in the animal kingdom? Defend your
answer.
Answer—Answers may vary depending on the classification used. Many students will
place the Echinoderms near the Cnidaria due to radial symmetry; others will place them
closer to the Annelids.
3. In the rainforest you discover a new species that is terrestrial, has determinate
development, molts during its lifetime, and possesses jointed appendages. To
which phyla of animals should it be assigned?
Answer—Determinate development indicates that it is a protostome and the fact that it
molts places it within the Ecdysozoa. The presence of jointed appendages makes it an
arthropod.
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