CHAPTER 31

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 rotifer B) a mollusk C) an annelid D) an arthropod E) a platyhelminth

E) a platyhelminth

Arthropods invaded land about 100 million years before vertebrates did so. This most clearly implies that ________. A) arthropods evolved before vertebrates did B) extant terrestrial arthropods are better adapted to terrestrial life than are extant terrestrial vertebrates C) ancestral arthropods must have been poorly adapted to aquatic life and thus experienced a selective pressure to invade land D) vertebrates evolved from arthropods E) arthropods have had more time to coevolve with land plants than have vertebrates

E) arthropods have had more time to coevolve with land plants than have vertebrates

The possession of two pairs of antennae is a characteristic of ________. A) spiders B) insects C) centipedes D) millipedes E) crustaceans

E) crustaceans

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 more closely related to an arthropod than a mollusk D) is motile E) is a suspension feeder

E) is a suspension feeder

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

E) sex organs

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) eating D) seeing E) smelling

E) smelling

What is the only group of Mollusca that does NOT have a radula? A) Bivalves B) Gastropods C) Chitons D) Cephalopods E) All mollusk have a radula.

A) Bivalves

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. 43) 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.

A) They are larval dragonflies, destined to undergo incomplete metamorphosis.

In your laboratory, you examine a vial of freshwater from a local pond. You notice several unfamiliar small (less than 1 millimeter in length) animals and decide to study them. You observe that the animals have a coelom, eat microscopic food particles, reproduce by parthenogenesis, and have offspring that do not undergo any larval stages. What else would you expect to observe about this organism? A) a corona B) a lophophore C) a scolex D) chaetae E) a mantle

A) a corona

Nematode worms and annelid worms share which of the following features? A) a digestive tract with two openings (a mouth and an anus) B) molting C) presence of a circulatory system D) presence of segmentation E) absence of species with parasitic lifestyles

A) a digestive tract with two openings (a mouth and an anus)

A land snail, a clam, and an octopus all have ________. A) a mantle B) a radula C) gills D) embryonic torsion E) distinct cephalization

A) a mantle

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

A) a mantle

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

A) bivalves

You find a wormlike animal while scuba diving and want to determine whether it is a nudibranch, a polychaete, or a flatworm. Finding which of the following traits would best help you classify the mystery animal? A) bristle-like structures on tiny appendages B) a coelom C) the ability to swim D) bright coloration E) sexual reproduction

A) bristle-like structures on tiny appendages

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

A) chelicerae

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

A) gills

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

A) mantle cavity

In adult arthropods, the hemocoel ________. A) provides space for the internal organs to grow and function B) forms a cavity to protect the visceral mass of organs C) acts as a hydrostatic skeleton for mobility D) secretes the exoskeleton

A) provides space for the internal organs to grow and function

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

A) rhinophores

You find a small animal with eight legs crawling up your bedroom wall. Closer examination will probably reveal that this animal also has ________. A) simple, but not compound, eyes B) two pairs of antennae C) a head, thorax, and abdomen D) tracheae and spiracles

A) simple, but not compound, eyes

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. E) Compare rates of predation on whitefly nymphs feeding on poisonous plants vs. those feeding on nonpoisonous plants.

B) Compare rates of predation on whitefly nymphs coated with a nontoxic dye vs. undyed whitefly nymphs

Adaptations to terrestrial environments evolved independently in arthropods, mollusks, nematodes, and annelids. What logical conclusion would you make from this statement? A) All these groups have a coelom. B) The common ancestor of all these groups was probably aquatic. C) All these groups have the same type of body plan. D) All these groups lost their coelom after moving to land.

B) The common ancestor of all these groups was probably aquatic.

Upon close inspection of movement in annelids and nematodes, you would notice an obvious difference. Nematodes tend to wriggle back and forth, while annelids tend to contract along their length as their girth swells and then thin out as they stretch. What anatomical feature explains this type of movement? A) The annelids possess longitudinal muscle fibers that the nematodes lack. B) The nematodes lack circular muscle fibers. C) Nematodes lack a coelom. D) Annelids have a highly specialized nervous system capable of more complex movements.

B) The nematodes lack circular muscle fibers.

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 E) not benefit the centipede at all

B) allow the centipede to retain more moisture in its tissues

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

B) dorsal plummules

You find a multilegged 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) the total number of legs D) egg-laying E) molting

B) poisonous fangs

Which adaptation is unique to insects among all protostomes? A) the ability to move via jointed limbs B) the ability to move by flying C) the ability to consume terrestrial plants D) the ability to parasitize other organisms E) the ability to metamorphose

B) the ability to move by flying

Among protostomes, which morphological trait has shown the most variation? A) type of symmetry (bilateral vs. radial vs. none) B) type of body cavity (coelom vs. pseudocoelom vs. no coelom) C) number of embryonic tissue types (diploblasty vs. triploblasty) D) type of development (protostome vs. deuterostome)

B) type of body cavity (coelom vs. pseudocoelom vs. no coelom)

Which 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) 1 B) 1 and 2 C) 1, 2, and 4 D) 2, 3, 4, and 5 E) 2 and 3

C) 1, 2, and 4

All arthropods ________. 1. undergo complete metamorphosis 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, and 5 D) 1, 4, and 5 E) 1, 2, and 3

C) 2, 3, 4, and 5

The protostome developmental sequence arose just once in evolutionary history, resulting in two main subgroups-Lophotrochozoa and Ecdysozoa. What does this finding suggest? A) These two subgroups have a common ancestor that was a deuterostome. B) The protostomes are a polyphyletic group. C) Division of these two groups occurred after the protostome developmental sequence appeared. D) The lophotrochozoans are monophyletic.

C) Division of these two groups occurred after the protostome developmental sequence appeared.

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 has a cuticle that it sheds to grow. B) It is a suspension feeder. C) It has no coelom. D) It is shaped like a worm. E) It has a mouth and an anus.

C) It has no coelom.

Which one of the following is a lophotrochozoan? A) Crustaceans B) Arthropods C) Mollusks D) Chelicerata E) Nematoda

C) Mollusks

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

C) Nematoda

The body cavity type for arthropods and mollusks can best be described as ________. A) a coelom B) a pseudocoelom C) a reduced coelom D) no coelom

C) a reduced coelom

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

C) cerata

Which mollusk group can be described as having several calcium carbonate plates along their dorsal side? A) bivalves B) gastropods C) chitons D) cephalopods

C) chitons

A cephalopod's tentacles are modified from its ________. A) mantle B) visceral mass C) foot D) shell E) radula

C) foot

A terrestrial mollusk without a shell belongs to which clade? A) chitons B) bivalves C) gastropods D) cephalopods

C) gastropods

Which mollusk clade includes members that undergo embryonic torsion? A) chitons B) bivalves C) gastropods D) cephalopods

C) gastropods

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) are lophotrochozoans E) have ciliated larvae

C) grow by shedding their exoskeleton

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

C) help retain moisture in terrestrial habitats

A(n) ________ has a crown of ciliated tentacles that function in feeding. A) trochophore B) lophotrochozoan C) lophophore D) cuticle E) ecdysozoan

C) lophophore

When considering the wormlike phyla within the protostomes, which feature is most useful in distinguishing groups? A) the presence of a mouth B) the presence or absence of a complete digestive system C) molting as they grow larger D) presence of a hydrostatic skeleton

C) molting as they grow larger

On which body segment are arthropod wings attached? A) head B) abdomen C) thorax D) evenly split between the abdomen and thorax

C) thorax

Compare the graphs in the accompanying figure 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.

D) C. morsitans lives in a drier habitat than does S. weberi.

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 the presence or absence of ________. 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

D) Nematoda; a circulatory system

The common ancestor of the protostomes had a coelom. What does this suggest? A) All lophotrochozoans have a coelom. B) There are no pseudocoelomates within the protostomes. C) There are no acoelomates within the protostomes. D) The body cavity evolved before the lophophore.

D) The body cavity evolved before the lophophore.

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

D) an open circulatory system

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

D) number of shell plates

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

D) wings