1. The ______of a mollusk is a highly-efficient respiratory structure.
a.nephridia
b.radula
c.ctenidia
d.veliger
The correct answer is c—
A. Answer a is incorrect. The nephridia are excretory structures.
The correct answer is c—
B. Answer b is incorrect. The radula is involved in feeding.
The correct answer is c—ctenidia
C. Answer c is correct.
The correct answer is c—
D. Answer d is incorrect. The veliger is a free-swimming larval stage of some mollusks.
2. Torsion is a unique characteristic of the ______.
a.bivalves
b.gastropods
c.chitons
d.cephalopods
The correct answer is b—
A. Answer a is incorrect. Torsion does not occur in the bivalves.
The correct answer is b—gastropods
B. Answer b is correct.
The correct answer is b—
C. Answer c is incorrect. Torsion does not occur in the chitons.
The correct answer is b—
D. Answer d is incorrect. Torsion does not occur in the cephalopods.
3. Elevated intelligence and complex behaviors are characteristics of the ______.
a.cephalopods
b.polychaetes
c.brachiopods
d.echinoderms
The correct answer is a—cephalopods
A. Answer a is correct.
The correct answer is a—
B. Answer b is incorrect. There is no evidence for elevated intelligence in this class of worms.
The correct answer is a—
C. Answer c is incorrect. This group of shelled invertebrates lacks intelligence.
The correct answer is a—
D. Answer d is incorrect. There is no evidence for elevated intelligence in the echinoderms.
4.Serial segmentation is a key characteristic of which of the following phyla?
a.Mollusks
b.Brachiopods
c. Bryozoa
d.Annelids
The correct answer is d—
A. Answer a is incorrect. The mollusks do not exhibit serial segmentation.
The correct answer is d—
B. Answer b is incorrect. The brachiopods do not exhibit serial segmentation.
The correct answer is d—
C. Answer c is incorrect. The bryozoans do not exhibit serial segmentation.
The correct answer is d—Annelids
D. Answer d is correct. Specialization of segments is one of the defining characteristics of this group of worms.
5. Which of the following forms of annelids is not hermaphroditic?
a.Earthworms
b.Leeches
c.Polychaetes
d.All annelids are hermaphroditic
The correct answer is c—
A. Answer a is incorrect. Earthworms are hermaphrodites.
The correct answer is c—
B. Answer b is incorrect. The majority of leeches are hermaphrodites.
The correct answer is c—Polychaetes
C. Answer c is correct. Most polychaetes utilize separate sexes.
The correct answer is c—
D. Answer d is incorrect. One of the above answers is not a hermaphrodite.
6. In annelids, which of the following chitin-based structures is used for the process of locomotion?
a.Clitellum
b.Chaetae
c. Septa
d.Parapodia
The correct answer is b—
A. Answer a is incorrect. The clitellum is a structure used for reproduction in earthworms and leeches.
The correct answer is b—Chaetae
B. Answer b is correct.
The correct answer is b—
C. Answer c is incorrect. Septa are structures that separate the segments.
The correct answer is b—
D. Answer d is incorrect. Although used in locomotion, parapodia are not made of chitin.
7. The distinguishing feature of the Bryozoa and Brachiopoda is the presence of ______.
a.a coelom
b.segmentation
c. chaetae
d.a lophophore
The correct answer is d—
A. Answer a is incorrect. Although Bryozoans are deuterostomes, the presence of a coelom does not distinguish it from other groups.
The correct answer is d—
B. Answer b is incorrect. The Bryozoans are not segmented.
The correct answer is d—
C. Answer c is incorrect. Bryozoans do not possess chaetae; these are present in the annelids.
The correct answer is d—a lophophore
D. Answer d is correct. A lophophore is a feeding structure of the bryozoans.
8. In terms of numbers, the most successful phylum on the planet is the ______.
a.Mollusca
b.Arthropoda
c.Echinodermata
d.Annelida
The correct answer is b—
A. Answer a is incorrect. Mollusks are the second-largest phylum.
The correct answer is b—Arthropoda
B. Answer b is correct.
The correct answer is b—
C. Answer c is incorrect. This phylum includes the sea stars and is a relatively small phylum.
The correct answer is b—
D. Answer d is correct. This phylum is smaller than both the mollusks and arthropods.
9. Which of the following characteristics is NOT found in the arthropods?
a.Jointed appendages
b.Segmentation
c.Closed circulatory system
d.Segmented ganglia
The correct answer is c—
A. Answer a is incorrect. Arthropods possess jointed appendages.
The correct answer is c—
B. Answer b is incorrect. Arthropods are one of the segmented phyla of the animal kingdom.
The correct answer is c—Closed circulatory system
C. Answer c is correct. Arthropods possess an open circulatory system.
The correct answer is c—
D. Answer d is incorrect. Segmented ganglia are a standard component of the arthropod nervous system.
10. The fact that Arthropods molt means that they are considered ______.
a.Spiralia
b.Ecdysozoa
c.Deuterostomes
d.Parazoa
The correct answer is b—
A. Answer a is incorrect. Spiralians are nonmolting animals. Review Figure 33.2 for an overview of the animal kingdom.
The correct answer is b—Ecdysozoa
B. Answer b is correct. Molting animals belong to the Ecdysozoa.
The correct answer is b—
C. Answer c is incorrect. Deuterostomes are nonmolting. Review Figure 33.2 for an overview of the animal kingdom.
The correct answer is b—
D. Answer d is incorrect. Parazoa are animals without tissues. Review Figure 33.2 for an overview of the animal kingdom.
11. Which of the following classes of arthropod possess chelicerae?
a.Chilopoda
b.Crustacea
c.Hexapoda
d.Arachnida
The correct answer is d—
A. Answer a is incorrect. These are the centipedes, which lack chelicerae.
The correct answer is d—
B. Answer b is incorrect. Chelicerae act as fangs or pincers, and are absent in the crustaceans.
The correct answer is d—
C. Answer c is incorrect. These are the insects, which lack chelicerae.
The correct answer is d—Arachnida
D. Answer d is correct. The chelicerae structures are a characteristic of this group.
12. Decapods are ______.
a.centipedes and millipedes
b.barnacles
c.ticks and mites
d.lobsters and crayfish
The correct answer is d—
A. Answer a is incorrect. These are chilopods and diplopods, respectively.
The correct answer is d—
B. Answer b is incorrect. These are sessile crustaceans.
The correct answer is d—
C. Answer c is incorrect. These belong to the order Acari.
The correct answer is d—lobsters and crayfish
D. Answer d is correct. Decapods are marine crustaceans with “10 feet.”
13. What characteristic separates the Diptera, Lepidoptera, and Hymenoptera?
a.Type of wings
b.Type of mouthparts
c.Type of legs
d.Method of reproduction
The correct answer is a—Type of wings
A. Answer a is correct.
The correct answer is a—
B. Answer b is incorrect. Refer to Table 34.2.
The correct answer is a—
C. Answer c is incorrect. Refer to Table 34.2.
The correct answer is a—
D. Answer d is incorrect. Refer to Table 34.2.
14. Based upon protostome-deuterostome characteristics, which of the following phyla is the closest relative to the chordates?
a.Annelida
b.Arthropoda
c.Echinodermata
d.Mollusca
The correct answer is c—
A. Answer a is incorrect. Chordates are deuterostomes; Annelida are protostomes.
The correct answer is c—
B. Answer b is incorrect. Chordates are deuterostomes; Arthropoda are protostomes
The correct answer is c—Echinodermata
C. Answer c is correct. Both phyla are deuterostomes.
The correct answer is c—
D. Answer d is incorrect. Chordates are deuterostomes; Mollusca are protostomes
15. Which of the following structures is NOT a component of the water-vascular system of an echinoderm?
a.Ossicles
b.Ampulla
c.Radial canals
d.Madreporite
The correct answer is a—Ossicles
A. Answer a is correct. Ossicles are part of the endoskeleton.
The correct answer is a—
B. Answer b is incorrect. Ampulla are muscular sacs in the water-vascular system.
The correct answer is a—
C. Answer c is incorrect. Radial canals move fluids within the water-vascular system.
The correct answer is a—
D. Answer d is incorrect. The madreporite acts as the entrance to the water-vascular system.
Challenge Questions
1. Scientists along the Chesapeake Bay have discovered that the decline in bivalve populations in the bay (specifically clams and scallops) has led to a drastic increase in the levels of pollution in the bay. What characteristic of this group could be attributed to this observation?
Answer—Bivalves are filter feeders that siphon large amounts of water through their bodies to obtain food. They act as natural pollution-control systems for bays and estuaries. A loss of bivalves (from overfishing, predation, or toxic chemicals) would upset the aquatic ecosystem and allow pollution levels to rise.
2. Chitin is present in a number of invertebrate coelomates, as well as fungi. What does this tell you about the origin and importance of this substance?
Answer—Chitin is an example of convergent evolution since these organisms do not share a common chitin-equipped ancestor. Chitin is often used in structures that need to withstand the rigors of stress (chaetae, exoskeletons, zoecium, etc.).
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Chapter 34