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

Answer: C

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

Answer: D

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

Answer: C

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

Answer: B

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

Answer: B

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

Answer: C

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

Answer: D

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

Answer: D

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

Answer: A

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) A
B) B
C) C
D) D

Answer: C

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

Answer: D

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.

Answer: B

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

Answer: D

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

Answer: D

19) Against which hard structure do the circular and longitudinal muscles of annelids work?
A) cuticle
B) shell
C) endoskeleton
D) hydrostatic skeleton

Answer: D

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

Answer: B

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

Answer: C

22) The nematocysts most likely reach the skin of sea slugs through branches of the _____.
A) intestine
B) excurrent siphon
C) nephridium
D) pseudocoelom

Answer: A

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

Answer: A

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.

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

Answer: C

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

Answer: D

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

Answer: A

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

Answer: C

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.

28) If the teacher wanted to show the students what a lophophore is and how it works, the teacher would point out a feeding _____.
A) hydra
B) sponge
C) gastropod
D) ectoproct

Answer: D

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.

29) The teacher was unaware of the difference between suspension feeding and predation. The teacher thought that providing live copepods (2 mm long) and feeder fish (2 cm long) would satisfy the dietary needs of all of the organisms. Consequently, which two organisms would have been among the first to starve to death (assuming they lack photosynthetic endosymbionts)?
A) sponges and corals
B) sea stars and sponges
C) shrimp and bivalves
D) bivalves and sponges

Answer: D

30) 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 population of the intermediate snail host
C) avoid contact with rodent droppings
D) carefully wash all raw fruits and vegetables

Answer: B

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.

31) 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) spring and summer

Answer: A

32) 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

Answer: A

33) Which one of these mollusk groups can be classified as suspension feeders?
A) bivalves
B) gastropods
C) chitons
D) cephalopods

Answer: A

34) Which characteristic is shared by cnidarians and flatworms?
A) dorsoventrally flattened bodies
B) radial symmetry
C) a digestive system with a single opening
D) a distinct head

Answer: C

35) If a lung were to be found in a mollusc, where would it be located?
A) mantle cavity
B) incurrent siphon
C) visceral mass
D) excurrent siphon

Answer: A

36) Parasitism is one of the most widespread life strategies ever to evolve. Which of the following is consistent with this finding?
A) Parasites almost always predigest their hosts' tissues and, therefore, spend less energy and require fewer structural adaptations.
B) Parasites, unlike predators, feed on almost all the tissues of their host.
C) Parasites do not generally kill their hosts; thus they can feed on the same host throughout the host's normal life span and do not have competition from decomposers.
D) Parasites generally kill their host and can feed for a very long time because they are much smaller than their host.

Answer: C

37) Nematodes and arthropods both _____.
A) develop an anus from the blastopore (pore) formed in the gastrula stage
B) are suspension feeders
C) grow by shedding their exoskeleton
D) have ciliated larvae

Answer: C

38) Arthropod exoskeletons and mollusk shells both _____.
A) completely replace the hydrostatic skeleton
B) are secreted by the mantle
C) help retain moisture in terrestrial habitats
D) are comprised of the polysaccharide chitin

Answer: C

39) You find a multi-legged animal in your garden and want to determine if it is a centipede or a millipede. You take the animal to a university where a myriapodologist quickly tells you that you have found a centipede. Which of the following may have allowed her to make this distinction?
A) segmentation
B) poisonous fangs
C) egg-laying
D) molting

Answer: B

40) Whiteflies are common pest insects found on cotton, tomato, poinsettia, and many other plants. Nymphs are translucent and mostly sessile, feeding on their host plants' phloem (sap) from the undersides of leaves. They undergo incomplete metamorphosis into winged adults. Because whitefly nymphs cannot escape predation by moving, you hypothesize that their translucent bodies make them hard to spot by predators. How could you directly test this hypothesis?
A) Compare rates of predation on whitefly nymphs on plant leaves of different colors (for example, red vs. green poinsettia leaves).
B) Compare rates of predation on whitefly nymphs coated with a nontoxic dye vs. undyed whitefly nymphs.
C) Compare rates of predation on whitefly nymphs vs. whitefly adults.
D) Compare rates of predation on whitefly nymphs by predators that are translucent vs. predators that are not translucent.

Answer: B

41) All arthropods _____.
1) undergo complete metamorphose
2) have jointed appendages
3) molt
4) have segmented bodies
5) have an exoskeleton or cuticle
A) 1, 2, and 4
B) 3 and 5
C) 2, 3, 4, 5
D) 1, 4, 5

Answer: C

Many terrestrial arthropods exchange gases with their environments by using tracheae, tubes that lead from openings (called spiracles) in the animal's exoskeleton or cuticle directly to the animal's tissues. Some arthropods can control whether their spiracles are opened or closed; opening the spiracles allows the carbon dioxide produced in the tissues to travel down the tracheae and be released outside the animal. Klok et al. measured the carbon dioxide emitted over time (represented by
) by several species of centipedes. The figure below presents graphs of their results for two species, Cormocephalus morsitans and Scutigerina weberi. (C. J. Klok, R. D. Mercer, and S. L. Chown. 2002. Discontinuous gas-exchange in centipedes and its convergent evolution in tracheated arthropods. Journal of Experimental Biology 205:1019-29.) Copyright 2002 The Company of Biologists and the Journal of Experimental Biology.

42) Look at the graph for Cormocephalus morsitans in the figure above. What is the best interpretation of these results?
A) The centipede had its spiracles open the entire time.
B) The centipede had its spiracles closed the entire time.
C) The centipede had its spiracles open when carbon dioxide (CO2) emission peaked and closed when CO2 emission was low.
D) The centipede had its spiracles closed when carbon dioxide (CO2) emission peaked and open when CO2 emission was low.

Answer: C

43) Look at the graph for Scutigerina weberi (note the scale of the y-axis) in the figure above. What is the best interpretation of these results?
A) The centipede had its spiracles open the entire time.
B) The centipede had its spiracles closed the entire time.
C) The centipede had its spiracles open when carbon dioxide (CO2) emission peaked and closed when CO2 emission was low.
D) The centipede had its spiracles closed when carbon dioxide (CO2) emission peaked and open when CO2 emission was low.

Answer: A

44) How would a terrestrial centipede most likely benefit from the ability to close its spiracles? Closing spiracles would _____.
A) allow the centipede to move more quickly
B) allow the centipede to retain more moisture in its tissues
C) allow the centipede to stay warmer
D) allow more oxygen from the environment to reach the centipede's tissues

Answer: B

45) Compare the graphs in the figure above of carbon dioxide (CO2) emission for Cormocephalus morsitans and Scutigerina weberi. What hypothesis can you make about each centipede's habitat?
A) C. morsitans lives in a habitat that provides more carbon dioxide than does S. weberi.
B) C. morsitans lives in a habitat with more predators than does S. weberi.
C) C. morsitans lives in a colder habitat than does S. weberi.
D) C. morsitans lives in a drier habitat than does S. weberi.

Answer: D

46) What would be the most direct effect of removing or damaging an insect's antennae? The insect would have trouble _____.
A) hearing
B) mating
C) seeing
D) smelling

Answer: D

47) 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) Annelida

Answer: C

48) 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

Answer: D

49) 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

Answer: A

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.

50) The claws (fangs) on the foremost trunk segment of centipedes have a function most similar to that of _____.
A) rhinophores
B) dorsal plummules
C) cerata
D) chemoreceptors

Answer: C

51) The stingers of honeybees have a function most similar to that of _____.
A) rhinophores
B) dorsal plummules
C) cerata
D) chemoreceptors

Answer: C

52) The spiracles and tracheae of insects have a function most similar to that of _____.
A) rhinophores
B) dorsal plummules
C) cerata.
D) chemoreceptors

Answer: B

53) The antennae of insects have a function most similar to that of _____.
A) rhinophores
B) dorsal plummules
C) cerata
D) chemoreceptors

Answer: A

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.

54) 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) sex organs

Answer: D

55) 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

Answer: A

56) As you are walking along a beach, you find an animal and believe that it belongs to the class Asteroidea. Which of the following characteristics would support your hypothesis that the animal is a sea star and not another type of echinoderm?
A) It is pentaradially symmetric.
B) It feeds on other animals.
C) It has a hydrostatic skeleton, formed from its water vascular system.
D) Its central region is not well-delineated from its appendages.

Answer: D

57) The water vascular system of echinoderms _____.
A) functions as a circulatory system that distributes nutrients to body cells
B) functions in locomotion and feeding
C) is bilateral in organization, even though the adult animal is not bilaterally symmetrical
D) is analogous to the gastrovascular cavity of flatworms

Answer: B

58) Which of the following combinations correctly matches a phylum to its description?
A) Echinodermata — bilateral symmetry as a larva, water vascular system
B) Nematoda — segmented worms, closed circulatory system
C) Cnidaria — flatworms, gastrovascular cavity, acoelomate
D) Platyhelminthes — radial symmetry, polyp and medusa body forms

Answer: A

59) Which of the following animal groups is entirely aquatic?
A) Mollusca
B) Crustacea
C) Echinodermata
D) Nematoda

Answer: C

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.

60) The bivalves started to die one by one; only the undamaged shells remained. To keep the remaining bivalves alive, the teacher would most likely need to remove the _____.
A) sea anemones
B) sea star
C) gastropods
D) ectoprocts

Answer: B