Campbell Biology, 10e (Reece)
Chapter 33 An Introduction to Invertebrates
1) One should expect to find cilia associated with the feeding apparatus of _____.
A) annelids
B) coral animals
C) tapeworms
D) sponges
2) Sponges _____.
A) have larvae which are motile and move via the motion of cilia
B) are the simplest diploblastic animals
C) have a nerve net but not a central nervous system
D) have feeding cells called dinoflagellates
3) Which of the following is most likely to be aquatic?
A) suspension feeder
B) mass feeder
C) deposit feeder
D) fluid feeder
4) Comb jellies may not be the most familiar animal to you, but they are critical in the food chain
because they make up a significant portion of the planktonic biomass. Their feeding strategy is
predatory and involves adhesives or mucus on their tentacles or other body parts. What feeding
tactic do these animals use?
A) suspension feeder
B) fluid feeder
C) deposit feeder
D) food-mass feeder
5) Which of the following can be found in the mesohyl of a sponge?
1. amoebocytes
2. spicules
3. spongin
4. zygotes
5. choanocytes
A) 1 and 2
B) 2, 3, 4
C) 1, 2, 3, and 4
D) 1, 2, 3, 4, and 5
6) Which of the following factors, when used to label the horizontal axis of the graph above,
would account most directly for the shape of the plot?
A) rate of cribrostatin synthesis (molecules/unit time)
B) number of pores per sponge
C) number of spicules per sponge
D) number of choanocytes per sponge
7) Most cnidarians are known to produce toxins. In fact, it has been claimed that one particular
species produces the most deadly of all toxins on the planet. What feature of this group most
likely evolved simultaneously with the evolution of these toxins?
A) the medusa body form
B) asexual reproduction
C) a slow-moving or sessile lifestyle in the adult
D) diploblastic design
8) Healthy corals are brightly colored because they _____.
A) secrete colorful pigments to attract mates
B) host symbionts with colorful photosynthetic pigments
C) build their skeletons from colorful minerals
D) secrete colorful pigments to protect themselves from ultraviolet light
9) In terms of food capture, which sponge cell is most similar to the cnidocyte of a cnidarian?
A) amoebocyte
B) choanocyte
C) epidermal cell
D) pore cell
10) The crown-of-thorns sea star, Acanthaster planci, preys on the flesh of live coral. If coral
animals are attacked by these sea stars, then what actually provides nutrition to the sea star, and
which chemical (besides the toxin within their nematocysts) do the corals rely on for protection?
A) medusae; silica
B) exoskeleton; calcium carbonate
C) polyps; calcium carbonate
D) polyps; silica
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Use the following information to answer the question(s) below.
An elementary school science teacher decided to liven up the classroom with a saltwater
aquarium. Knowing that saltwater aquaria can be quite a hassle, the teacher proceeded stepwise.
First, the teacher conditioned the water. Next, the teacher decided to stock the tank with various
marine invertebrates, including a polychaete, a siliceous sponge, several bivalves, a shrimp,
several sea anemones of different types, a colonial hydra, a few coral species, an ectoproct, a sea
star, and several herbivorous gastropod varieties. Lastly, she added some vertebrates—a
parrotfish and a clownfish. She arranged for daily feedings of copepods and feeder fish.
11) One day, Tommy, a student in an undersupervised class of forty fifth graders, got the urge to
pet Nemo (the clownfish), who was swimming among the waving petals of a pretty underwater
“flower” that had a big hole in the midst of the petals. Tommy giggled upon finding that these
petals felt sticky. A few hours later, Tommy was in the nurse’s office with nausea and cramps.
Microscopic examination of his fingers would probably have revealed the presence of _____.
A) teeth marks
B) spines
C) spicules
D) nematocysts
12) The teacher and class were especially saddened when the colonial hydrozoan died. They had
watched it carefully, and the unfortunate creature never even got to produce offspring by
budding. Yet, everyone was elated when one of the students noticed a small colonial hydrozoan
growing in a part of the tank far from the location of the original colony. The teacher was
apparently unaware that these hydrozoans exhibit _____.
A) spontaneous generation
B) abiogenesis
C) alternation of generations
D) a medusa stage
5
13) The sharp, inch-long thorns of the crown-of-thorns sea star are its spines. These spines,
unlike those of most other sea stars, contain a potent toxin. If it were discovered that crown-of-
thorns sea stars do not make this toxin themselves, then the most likely alternative would be that
this toxin is _____.
A) derived from the nematocysts of its prey
B) absorbed from the surrounding seawater
C) an endotoxin of cellulose-digesting bacteria that inhabit the sea star’s digestive glands
D) injected into individual thorns by mutualistic corals which live on the aboral surfaces of these
sea stars
6
Use the following information to answer the question(s) below.
An elementary school science teacher decided to liven up the classroom with a saltwater
aquarium. Knowing that saltwater aquaria can be quite a hassle, the teacher proceeded stepwise.
First, the teacher conditioned the water. Next, the teacher decided to stock the tank with various
marine invertebrates, including a polychaete, a siliceous sponge, several bivalves, a shrimp,
several sea anemones of different types, a colonial hydra, a few coral species, an ectoproct, a sea
star, and several herbivorous gastropod varieties. Lastly, she added some vertebrates—a
parrotfish and a clownfish. She arranged for daily feedings of copepods and feeder fish.
14) The clownfish readily swims among the tentacles of the sea anemones; the parrotfish avoids
them. One hypothesis for the clownfish’s apparent immunity is that they slowly build a tolerance
to the sea anemone’s toxin. A second hypothesis is that a chemical in the mucus that coats the
clownfish prevents the nematocysts from being triggered. Which of the following graphs
supports the second, but not the first, of these hypotheses?
A)
B)
C)
D)
15) The presence of a lophophore in a newly discovered species would suggest that the species
_____.
A) has an exoskeleton
B) grows by shedding its external covering
C) is motile
D) is a suspension feeder
16) You find what you believe is a new species of animal. Which of the following characteristics
would enable you to argue that it is more closely related to a flatworm than it is to a roundworm?
A) It is a suspension feeder.
B) It has no coelom.
C) It is shaped like a worm.
D) It has a mouth and an anus.
17) What would be the best anatomical feature to look for to distinguish a gastropod from a
chiton?
A) presence of a muscular foot
B) presence of a rasp-like feeding structure
C) production of eggs
D) number of shell plates
18) Which of the following organisms would you expect to have the largest surface-area-to–
volume ratio? Assume that all of the following are the same total length.
A) a mollusk
B) an annelid
C) an arthropod
D) a platyhelminth
19) Against which hard structure do the circular and longitudinal muscles of annelids work?
A) cuticle
B) shell
C) endoskeleton
D) hydrostatic skeleton
20) While sampling marine plankton in a lab, a student encounters large numbers of fertilized
eggs. The student rears some of the eggs in the laboratory for further study and finds that the
blastopore becomes the mouth. The embryo develops into a trochophore larva and eventually has
a true coelom. These eggs probably belonged to a(n) _____.
A) echinoderm
B) mollusc
C) nematode
D) arthropod
This nudibranch, a type of sea slug, has many reddish cerata on its dorsal surface, as well as two
white-tipped rhinophores located on the head.
The nontaxonomic term sea slug encompasses a wide variety of marine gastropods. One feature
they share as adults is the lack of a shell. We might think, therefore, that they represent
defenseless morsels for predators. In fact, sea slugs have multiple defenses. Some sea slugs prey
on sponges and concentrate sponge toxins in their tissues. Others feed on cnidarians, digesting
everything except the nematocysts, which they then transfer to their own skins. Whereas the
most brightly colored sea slugs are often highly toxic, others are nontoxic and mimic the
coloration of the toxic species. Their colors are mostly derived from pigments in their prey.
There are also sea slugs that use their coloration to blend into their environments.
21) Which structure do sea slugs use to feed on their prey?
A) nematocysts
B) an incurrent siphon
C) a radula
D) a mantle cavity
22) The nematocysts most likely reach the skin of sea slugs through branches of the _____.
A) intestine
B) excurrent siphon
C) nephridium
D) pseudocoelom
23) The nematocysts of sea slugs should be most effective at protecting individual sea slugs from
predation if the predators _____.
A) remove small bites of flesh from sea slugs and have long-term memory
B) remove small bites of flesh from sea slugs and have no long-term memory
C) consume entire sea slugs in one gulp and have no long-term memory
D) consume entire sea slugs in one gulp and have long-term memory
Use the following information and figure to answer the question(s) below.
The sea slug Pteraeolidia ianthina (P. ianthina) can harbor living dinoflagellates (photosynthetic
protists) in its skin. These endosymbiotic dinoflagellates reproduce quickly enough to maintain
their populations. Low populations do not affect the sea slugs very much, but high populations (>
5 x 105 cells/mg of sea slug protein) can promote sea slug survival.
Percent of sea slug respiratory carbon demand provided by indwelling dinoflagellates.
24) If the dinoflagellate-containing sea slug P. ianthina preys on coral animals, then it would be
LEAST surprising to find that _____.
A) P. ianthina has no tolerance to the toxin in the nematocysts of its prey
B) P. ianthina can locate its coral prey by chemicals released into the water by corals
C) the coral prey harbor dinoflagellates in their tissues
D) the coral prey transform themselves into medusas to flee from approaching P. ianthina
25) The sea slug Elysia chorotica has no nematocysts or dinoflagellates but, rather, has “naked”
chloroplasts in its skin. The chloroplasts are all that remain of the seaweed (Vaucheria sp.) that
Elysia feeds upon. The chloroplasts are transferred to the skin; consequently, this slug is green. It
spends most of its time basking in shallow water on the surface of seaweeds. How should we
expect its chloroplasts to benefit the Elysia sea slug?
1. provide Elysia with fixed carbon dioxide
2. provide Elysia with fixed nitrogen
3. provide Elysia with protective coloration
A) 1 only
B) 2 only
C) 3 only
D) 1 and 3
Use the following information to answer the question(s) below.
Nudibranchs, a type of predatory sea slug, can have various protuberances (that is, extensions)
on their dorsal surfaces. Rhinophores are paired structures, located close to the head, which bear
many chemoreceptors. Dorsal plummules, usually located posteriorly, perform respiratory gas
exchange. Cerata usually cover much of the dorsal surface and contain nematocysts at their tips.
26) Nudibranchs usually have two rhinophores. However, if they had a single rhinophore, it
could still carry out the function of two rhinophores, and with similar effectiveness, if this single
rhinophore _____.
A) had two branches, one directed to the left, the other to the right
B) was located within the mantle cavity
C) was as long as two rhinophores placed end to end
D) had cilia whose power strokes directed water away from the surface of the slug
27) A natural predator of the crown-of-thorns sea star is a mollusc called the Giant Triton,
Charonia tritonis. If the triton uses a radula to saw into the sea star, then to which clade should
the triton belong?
A) chitons
B) bivalves
C) gastropods
D) cephalopods