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.
Answer: C
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.
Answer: A
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.
Answer: C
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.
Answer: B
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.
Answer: A
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.
Answer: A
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.
Answer: B
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.
Answer: C
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.
Answer: B
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.
Answer: C
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.
Answer: A
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.
Answer: C
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.
Answer: A
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
Answer: D
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.
Answer: D
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
Answer: C
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
Answer: B
