Deck 33: An Introduction to Invertebrates

Question 1

Which chemical is synthesized by some sponges and acts as an antibiotic?

A) streptomycin
B) spongin
C) calcium carbonate
D) silica
E) cribrostatin

Answer 1

E

Question 2

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

Answer 2

B

Question 3

A brachiopod can be distinguished from a bivalve by the presence of

A) two hinged shells.
B) a digestive system with separate mouth and anus.
C) a lophophore.
D) suspension feeding.
E) a distinct head.

Answer 3

C

Question 4

A sponge's structural materials (spicules, spongin)are manufactured by the

A) pore cells.
B) epidermal cells.
C) choanocytes.
D) amoebocytes.

Question 5

If a lung were to be found in a mollusc, where would it be located?

A) mantle cavity
B) coelom
C) incurrent siphon
D) visceral mass
E) excurrent siphon

Question 6

Which clade in the phylum Cnidaria includes "jellies" with rounded (as opposed to boxlike)medusae?

A) Hydrozoa
B) Scyphozoa
C) Anthozoa
D) Cubozoa

Question 7

The larvae of many common tapeworm species that infect humans are usually found

A) encysted in freshwater snails.
B) encysted in the muscles of an animal, such as a cow or pig.
C) crawling in the abdominal blood vessels of cows and pigs.
D) crawling in the intestines of cows and pigs.

Question 8

Which characteristic(s)is (are)shared by both cnidarians and flatworms?

A) dorsoventrally flattened bodies
B) true muscle
C) radial symmetry
D) a digestive system with a single opening
E) two of these

Question 9

The members of which clade in the phylum Cnidaria occur only as polyps?

A) Hydrozoa
B) Scyphozoa
C) Anthozoa
D) Cubozoa

Question 10

What would be the most effective method of reducing the incidence of blood flukes in a human population?

A) reduce the mosquito population
B) reduce the freshwater snail population
C) purify all drinking water
D) avoid contact with rodent droppings
E) carefully wash all raw fruits and vegetables

Question 11

The excretory organs of annelids are

A) protonephridia.
B) flame bulbs.
C) metanephridia.
D) skin gills.
E) malpighian tubules.

Question 12

Which of the following is true of members of the phylum Cnidaria?

A) They are not capable of locomotion because they lack true muscle tissue.
B) They are primarily filter feeders.
C) They have either, or both, of two body forms: mobile polyps and sessile medusae.
D) They may use a gastrovascular cavity as a hydrostatic skeleton.
E) They are the simplest organisms with a complete alimentary canal (two openings).

Question 13

The organ(s)of respiratory gas exchange in oligochaetes is (are)

A) parapodia.
B) gills.
C) the skin.
D) book lungs.
E) pairs of hollow bristles.

Question 14

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) chordate.
B) echinoderm.
C) mollusc.
D) nematode.
E) arthropod.

Question 15

Planarians lack dedicated respiratory and circulatory systems because

A) none of their cells are far removed from the gastrovascular cavity or from the external environment.
B) they lack mesoderm as embryos and, therefore, lack the adult tissues derived from mesoderm.
C) their flame bulbs can carry out respiratory and circulatory functions.
D) their body cavity, a pseudocoelom, carries out these functions.

Question 16

Against which hard structure do the circular and longitudinal muscles of annelids work?

A) bristles
B) cuticle
C) shell
D) endoskeleton
E) hydrostatic skeleton

Question 17

Sponges are most accurately described as

A) marine predators.
B) marine filter feeders.
C) freshwater scavengers.
D) aquatic filter feeders.
E) aquatic predators.

Question 18

Corals are most closely related to which group?

A) jellies
B) freshwater hydras
C) sea anemones
D) sponges
E) barnacles

Question 19

How many of the following can be observed in the mesohyl of various undisturbed sponges at one time or another?
1)amoebocytes
2)spicules
3)spongin
4)zygotes
5)choanocytes

A) one of these
B) two of these
C) three of these
D) four of these
E) five of these

Question 20

How many of the following are characteristics of at least some members of the phylum Cnidaria?
1)a gastrovascular cavity
2)a polyp stage
3)a medusa stage
4)cnidocytes
5)a pseudocoelom

A) one of these
B) two of these
C) three of these
D) four of these
E) five of these

Question 21

A radula is present in members of which clade(s)?

A) chitons
B) bivalves
C) gastropods
D) cephalopods
E) both chitons and gastropods

Question 22

How many of the following are characteristics of arthropods?
1)protostome development
2)bilateral symmetry
3)a pseudocoelom
4)three embryonic germ layers
5)a closed circulatory system

A) one of these
B) two of these
C) three of these
D) four of these
E) five of these

Question 23

A terrestrial animal species is discovered with the following larval characteristics: exoskeleton, system of tubes for gas exchange, and modified segmentation. A knowledgeable zoologist should predict that the adults of this species would also feature

A) eight legs.
B) two pairs of antennae.
C) a sessile lifestyle.
D) an open circulatory system.
E) parapodia.

Question 24

Nematode worms and annelid worms share which of the following features?

A) use of fluid in the body cavity as a hydrostatic skeleton
B) ecdysis
C) presence of a circulatory system
D) presence of segmentation
E) absence of species with parasitic lifestyles

Question 25

What distinguishes complete metamorphosis from incomplete metamorphosis in insects?

A) the presence of wings in the adult, but not in earlier life stages
B) the presence of sex organs in the adult, but not in earlier life stages
C) the radically different appearance between adults and earlier life stages
D) Three of these responses are correct.
E) Two of these responses are correct.

Question 26

One should expect to find the "9 + 2 pattern" of microtubules in association with the feeding apparatus of which of the following?

A) annelids
B) coral animals
C) tapeworms
D) sponges
E) terrestrial insects

Question 27

How many of the following can be used to distinguish a nematode worm from an annelid worm?
1)type of body cavity
2)number of muscle layers in the body wall
3)presence of segmentation
4)number of embryonic tissue layers
5)shape of worm in cross-sectional view

A) one of these
B) two of these
C) three of these
D) four of these
E) five of these

Question 28

Infection with which parasite might cause excessive elasticity in human skeletal muscles?

A) trichinella worms
B) tapeworms
C) copepods
D) blood flukes
E) rotifers

Question 29

Which of the following is found only among annelids?

A) a hydrostatic skeleton
B) segmentation
C) a clitellum
D) a closed circulatory system
E) a cuticle made of chitin

Question 30

Among the invertebrate phyla, phylum Arthropoda is unique in possessing members that have

A) a cuticle.
B) a ventral nerve cord.
C) open circulation.
D) wings.
E) segmented bodies.

Question 31

The possession of two pairs of antennae is a characteristic of

A) spiders.
B) insects.
C) centipedes.
D) millipedes.
E) crustaceans.

Question 32

Which of the following are entirely, or partly, composed of calcium carbonate?

A) spicules of siliceous sponges
B) coral animals' exoskeletons
C) molluscs' mantles
D) insects' cuticles
E) nematodes' cuticles

Question 33

Which mollusc clade includes members that undergo embryonic torsion?

A) chitons
B) bivalves
C) gastropods
D) cephalopods

Question 34

The heartworms that can accumulate within the hearts of dogs and other mammals have a pseudocoelom, an alimentary canal, and an outer covering that is occasionally shed. To which phylum does the heartworm belong?

A) Platyhelminthes
B) Arthropoda
C) Nematoda
D) Acoela
E) Annelida

Question 35

You find a small animal with eight legs crawling up your bedroom wall. Closer examination will probably reveal that this animal has

A) simple, but not compound, eyes.
B) two pairs of antennae.
C) a head, thorax, and abdomen.
D) tracheae and spiracles.
E) more than one of these.

Question 36

A shared derived characteristic for members of the arthropod subgroup that includes spiders would be the presence of

A) chelicerae.
B) an open circulatory system.
C) an exoskeleton.
D) a cuticle.
E) a cephalothorax.

Question 37

A student observes a wormlike organism crawling about on dead organic matter. Later, the organism sheds its outer covering. One possibility is that the organism is a larval insect (like a maggot). However, it might be a member of the phylum ________, and one way to distinguish between the two possibilities is by looking for ________.

A) Platyhelminthes; a cuticle of chitin
B) Nematoda; an alimentary canal
C) Annelida; a body cavity
D) Nematoda; a circulatory system
E) Annelida; muscle in the body wall

Question 38

Humans most frequently acquire trichinosis by

A) having sexual contact with an infected partner.
B) eating undercooked pork.
C) inhaling the eggs of worms.
D) eating undercooked beef.
E) being bitten by tsetse flies.

Question 39

Which of the following is a characteristic of nematodes?

A) All species can be characterized as scavengers.
B) They have only longitudinal muscles.
C) They have a true coelom.
D) They have a gastrovascular cavity.
E) Many species are diploblastic.

Question 40

A terrestrial mollusc without a shell belongs to which clade?

A) chitons
B) bivalves
C) gastropods
D) cephalopods

Question 41

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.

Question 42

Percent of sea slug respiratory carbon demand provided by indwelling dinoflagellates.
According to the graph, during which season(s)of the year is the relationship between the sea slug and its dinoflagellates closest to being commensal?

A) winter
B) spring
C) summer
D) fall
E) spring and fall

Question 43

Which of the following describe(s)echinoderms?

A) They have an exoskeleton of hard calcareous plates.
B) Tubefeet provide motility in most species.
C) Digestion occurs completely outside of the organism.
D) Hemolymph circulates in the water vascular system.
E) They are found in both freshwater and saltwater environments.

Question 44

In a tide pool, a student encounters an organism with a hard outer covering that contains much calcium carbonate, an open circulatory system, and gills. The organism could potentially be a crab, a shrimp, a barnacle, or a bivalve. The presence of which of the following structures would allow for the most certain identification of the organism?

A) a mantle
B) a heart
C) a body cavity
D) a filter-feeding apparatus
E) eyes

Question 45

Which of the following animal groups is entirely aquatic?

A) Mollusca
B) Crustacea
C) Echinodermata
D) Nematoda
E) Platyhelminthes

Question 46

Nudibranchs, a type of predatory sea slug, can have various protuberances (i.e., 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.
The feet of certain insects, notably of female butterflies, have a function most similar to that of

A) rhinophores.
B) dorsal plummules.
C) cerata.
D) more than one of these.

Question 47

The sea slug, Pteraeolidia 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.
If 100,000 sea slug cells together contain 1.0 mg of protein, then what is the minimum number of dinoflagellates per sea slug cell that constitutes a "high," and therefore beneficial, population?

A) 1 cell
B) 5 cells
C) 10 cells
D) 50 cells
E) 100 cells

Question 48

Which of the following is a characteristic of adult echinoderms?

A) bilateral symmetry
B) spiral cleavage
C) gastrovascular cavity
D) exoskeleton
E) lophophore

Question 49

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.
Sea slugs can obtain nematocysts by preying on sea

A) anemones.
B) urchins.
C) daisies.
D) cucumbers.
E) lilies.

Question 50

A stalked, sessile marine organism has several feathery feeding structures surrounding an opening through which food enters. The organism could potentially be a cnidarian, a lophophorate, a tube-dwelling worm, a crustacean, or an echinoderm. Which of the following traits, if found in this organism, would allow the greatest certainty of identification?

A) the presence of what seems to be radial symmetry
B) a hard covering made partly of calcium carbonate
C) a digestive system with mouth and anus separate from each other
D) a water vascular system
E) a nervous system

Question 51

Nudibranchs, a type of predatory sea slug, can have various protuberances (i.e., 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.
The claws on the foremost trunk segment of centipedes have a function most similar to that of

A) rhinophores.
B) dorsal plummules.
C) cerata.
D) more than one of these.

Question 52

Percent of sea slug respiratory carbon demand provided by indwelling dinoflagellates.
If we assume that carbon is the sole nutrient needed by sea slugs to drive their cellular respiration, then based on the graph, during which season(s)is it least necessary for P. ianthina to act as a chemoheterotroph?

A) winter
B) spring
C) summer
D) fall
E) spring and fall

Question 53

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.
By which structures are nematocysts most likely to reach the skin of sea slugs?

A) the closed circulatory system
B) branches of the intestine
C) branches of the excurrent siphon
D) branches of the nephridium
E) branches of the pseudocoelom

Question 54

Which of the following factors, when used to label the horizontal axis of the previous graph, would account most directly for the shape of the plot?

A) spongin concentration (gm/unit volume)
B) rate of cribrostatin synthesis (molecules/unit time)
C) number of pores per sponge
D) number of spicules per sponge
E) number of choanocytes per sponge

Question 55

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 CO₂
2)provide Elysia with fixed N₂
3)provide Elysia with protective coloration

A) 1 only
B) 2 only
C) 3 only
D) 1 and 3
E) 1, 2, and 3

Question 56

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.
Which structure do sea slugs use to feed on their prey?

A) nematocysts
B) a sharp beak
C) an incurrent siphon
D) a radula
E) a mantle cavity

Question 57

Nudibranchs, a type of predatory sea slug, can have various protuberances (i.e., 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.
The stingers of honeybees have a function most similar to that of

A) rhinophores.
B) dorsal plummules.
C) cerata.
D) more than one of these.

Question 58

If the dinoflagellate-containing sea slug, P. ianthina, otherwise 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.

Question 59

Aside from the density of dinoflagellates in P. ianthina skin, how many of the following factors can affect whether or not the endosymbiotic dinoflagellates promote the sea slug's survival (assuming latitudes above or below Earth's equator)?
1)day length
2)height of sun above the horizon
3)cloud cover
4)depth at which P. ianthina lives
5)water clarity

A) two of these
B) three of these
C) four of these
D) five of these

Question 60

Which of the following is a diploblastic phylum of aquatic predators?

A) Cnidaria
B) Annelida
C) Mollusca
D) Arthropoda
E) Echinodermata

Question 61

A farm pond, usually dry during winter, has plenty of water and aquatic pond life during the summer. One summer, Sarah returns to the family farm from college. Observing the pond, she is fascinated by some six-legged organisms that can crawl about on submerged surfaces or, when disturbed, seemingly "jet" through the water. Watching further, she is able to conclude that the "mystery organisms" are ambush predators, and their prey includes everything from insects to small fish and tadpoles.
Sarah had learned that ancestral (Carboniferous era)dragonfly species were much larger than extant dragonfly species are, with wingspans of 70 cm. This struck her as odd, because she had also learned that one of the things that keeps insects small is their relatively inefficient respiratory system. Which two hypotheses might help account for the large size of ancestral dragonflies?
1)If the atmosphere during the Carboniferous era had featured a higher oxygen content than the modern atmosphere, then the tracheae might have been a sufficient means for oxygen delivery to the interior tissues.
2)If large size was a drawback, then the large dragonflies underwent extinction, which explains why all extant dragonflies are smaller.
3)If the ancestral dragonflies had possessed muscles that permitted effective ventilation of the tracheae, then the tracheae might have been a sufficient means for oxygen delivery to the interior tissues.
4)If ancestral dragonflies existed during greenhouse conditions, then they must have survived by decreasing their activity levels, such as no longer capturing prey in flight. Thus, for them, an ineffective respiratory system was sufficient.

A) 1 and 2
B) 1 and 3
C) 1 and 4
D) 2 and 3
E) 2 and 4

Question 62

A farm pond, usually dry during winter, has plenty of water and aquatic pond life during the summer. One summer, Sarah returns to the family farm from college. Observing the pond, she is fascinated by some six-legged organisms that can crawl about on submerged surfaces or, when disturbed, seemingly "jet" through the water. Watching further, she is able to conclude that the "mystery organisms" are ambush predators, and their prey includes everything from insects to small fish and tadpoles.
Sarah observed that the mystery pond organisms never come up to the pond's surface. If she catches one of these organisms and observes closely, perhaps dissecting the organism, she should find

A) gills.
B) spiracles.
C) tracheae.
D) book lungs.

Question 63

Nudibranchs, a type of predatory sea slug, can have various protuberances (i.e., 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.
The spines of sea stars have a function most similar to that of

A) rhinophores.
B) dorsal plummules.
C) cerata.
D) more than one of these.

Question 64

The reason their exoskeletons cannot protect the corals from sea stars is that the sea star

A) is immune to the toxin of the nematocysts.
B) thorns are sharp and toxic.
C) tubefeet act as tiny syringes that suck the corals out of their exoskeletons.
D) stomach can be everted, and can release digestive juices directly onto the corals.

Question 65

Nudibranchs, a type of predatory sea slug, can have various protuberances (i.e., 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.
The small, thin extensions of the skin on the aboral surfaces of sea stars have a function most similar to that of

A) rhinophores.
B) dorsal plummules.
C) cerata.
D) more than one of these.

Question 66

Nudibranchs, a type of predatory sea slug, can have various protuberances (i.e., 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.
The antennae of insects have a function most similar to that of

A) rhinophores.
B) dorsal plummules.
C) cerata.
D) more than one of these.

Question 67

A farm pond, usually dry during winter, has plenty of water and aquatic pond life during the summer. One summer, Sarah returns to the family farm from college. Observing the pond, she is fascinated by some six-legged organisms that can crawl about on submerged surfaces or, when disturbed, seemingly "jet" through the water. Watching further, she is able to conclude that the "mystery organisms" are ambush predators, and their prey includes everything from insects to small fish and tadpoles.
If the pond organisms are larvae, rather than adults, Sarah should expect them to have all of the following structures, except

A) antennae.
B) an open circulatory system.
C) an exoskeleton of chitin.
D) complex eyes.
E) sex organs.

Question 68

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.

Question 69

A farm pond, usually dry during winter, has plenty of water and aquatic pond life during the summer. One summer, Sarah returns to the family farm from college. Observing the pond, she is fascinated by some six-legged organisms that can crawl about on submerged surfaces or, when disturbed, seemingly "jet" through the water. Watching further, she is able to conclude that the "mystery organisms" are ambush predators, and their prey includes everything from insects to small fish and tadpoles.
From this description, one can conclude that the organisms that have caught Sarah's attention are

A) insects.
B) crustaceans.
C) aquatic spiders.
D) myriapods.
E) eurypterids.

Question 70

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) had two branches, one directed toward the head, the other directed toward the tail.
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.
E) was located within the mantle cavity.

Question 71

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) medusas; silica
B) exoskeleton; silica
C) exoskeleton; calcium carbonate
D) polyps; calcium carbonate
E) polyps; silica

Question 72

The crown-of-thorns sea star, Acanthaster planci, preys on the flesh of live coral. At times, these sea stars undergo poorly understood population explosions. What impact should such explosions have on those sea slugs that bear cerata (cerata contain nematocysts)? Population explosions of this sea star should

A) benefit sea slugs by distracting their prey.
B) benefit sea slugs by helping subdue their prey.
C) harm sea slugs by competing with them for food.
D) harm sea slugs by consuming them as food.
E) harm sea slugs by fouling the water with their feces.

Question 73

Nudibranchs, a type of predatory sea slug, can have various protuberances (i.e., 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.
The spiracles and tracheae of insects have a function most similar to that of

A) rhinophores.
B) dorsal plummules.
C) cerata.
D) more than one of these.

Question 74

A farm pond, usually dry during winter, has plenty of water and aquatic pond life during the summer. One summer, Sarah returns to the family farm from college. Observing the pond, she is fascinated by some six-legged organisms that can crawl about on submerged surfaces or, when disturbed, seemingly "jet" through the water. Watching further, she is able to conclude that the "mystery organisms" are ambush predators, and their prey includes everything from insects to small fish and tadpoles.
Sarah noticed the presence of many empty exoskeletons attached to emergent vegetation. These exoskeletons looked exactly like those of the largest of the "mystery organisms" she had seen in the pond. They also looked similar to the bodies of the dragonflies that patrolled the surface of the pond. If Sarah had learned a lot from her college biology class, what should she have concluded about the mysterious pond organisms?

A) They are larval dragonflies, destined to undergo incomplete metamorphosis.
B) They are larval dragonflies, destined to undergo complete metamorphosis.
C) They are adult dragonflies, so old that they can no longer fly, have fallen into the pond, but have not yet drowned.
D) They are adult dragonflies that must, like many amphibian species, return to water in order to mate.

Question 75

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.
One day, little Tommy (a student in an undersupervised class of 40 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.
E) a radula.

Question 76

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

Question 77

Nudibranchs, a type of predatory sea slug, can have various protuberances (i.e., 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.
The lateral flaps of planaria heads have a function most similar to that of

A) rhinophores.
B) dorsal plummules.
C) cerata.
D) more than one of these.

Question 78

Which human profession is most analogous to the lifestyle of the sea slugs described in this scenario?

A) physician
B) pirate
C) pharmacist
D) plumber
E) painter

Question 79

Nudibranchs, a type of predatory sea slug, can have various protuberances (i.e., 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.
The parapodia of polychaetes have a function most similar to that of

A) rhinophores.
B) dorsal plummules.
C) cerata.
D) more than one of these.

Question 80

If nudibranch rhinophores are located at the anteriors of these sea slugs, then they contribute to the sea slugs'

A) segmentation.
B) lack of torsion.
C) cephalization.
D) identity as lophotrochozoans.
E) ability to successfully carry out a sessile lifestyle.