Deck 32: Protostome Animals

Question 1

The evolution of a chitinous exoskeleton affected many aspects of arthropod evolution. The aspect that was least affected was the

A) division of labor among the body parts.
B) mode of locomotion.
C) pattern of growth.
D) system of gas exchange.
E) mode of digestion.

Answer 1

E

Question 2

Factors that may have contributed to the remarkable evolutionary success of insects include

A) the lack of any other similar organisms in the terrestrial environments colonized by insects.
B) the ability to fly.
C) complete metamorphosis.
D) a new mechanism for delivering oxygen to their internal tissues.
E) All of the above

Answer 2

E

Question 3

Which of the following animals have complete digestive tracts?

A) Flukes
B) Tapeworms
C) Horsehair worms
D) Annelids
E) None of the above

Answer 3

D

Question 4

Spiral cleavage is found in a subset of lophotrchozoans, including the ribbon worms, annelids, and

A) phoronids.
B) mollusks.
C) bryozoans.
D) rotifers.
E) flatworms.

Question 5

The firm exoskeleton of insects has protective and supportive advantages, but it poses which of the following problems?

A) The animal must consume large amounts of food to support the growth of the exoskeleton.
B) The exoskeleton prevents the animal from moving rapidly.
C) The exoskeleton cannot grow as the animal body inside it grows.
D) The exoskeleton attracts predators.
E) All of the above

Question 6

Which groups are arthropod relatives with unjointed legs?

A) Trilobites and onychophorans
B) Onychophorans and tardigrades
C) Trilobites and tardigrades
D) Onychophorans and chelicerates
E) Tardigrades and chelicerates

Question 7

The outer covering of ecdysozoans

A) is always hard and rigid.
B) is always thin and flexible.
C) is hard and rigid in larvae but thin in adults.
D) ranges from very thin to hard and rigid depending on the species.
E) grows throughout life to accommodate a growing body.

Question 8

The arthropod exoskeleton is composed of a

A) mixture of several kinds of polysaccharides.
B) mixture of several kinds of proteins.
C) single complex polysaccharide called chitin.
D) single complex protein called arthropodin.
E) mixture of layers of proteins and a polysaccharide called chitin.

Question 9

Which of the following is not one of the traits that unite the protostomes?

A) Dorsal nervous system
B) Anterior brain
C) Bilaterally symmetrical body plan
D) Development of a mouth from a blastopore (in many species)
E) All of the above

Question 10

Animals with thin cuticles are generally restricted to moist habitats because

A) the thin cuticle causes water to be lost across the body surface.
B) there are fewer predators in these habitats.
C) these animals rely on flowing water to bring them food.
D) All of the above
E) None of the above

Question 11

The body plan of insects is composed of which of the three following regions?

A) Head, abdomen, and trachea
B) Head, abdomen, and cephalothorax
C) Cephalothorax, abdomen, and trachea
D) Head, thorax, and abdomen
E) Abdomen, trachea, and mantle

Question 12

Members of which groups have lophophores?

A) Phoronids, brachiopods, and nematodes
B) Phoronids, brachiopods, and bryozoans
C) Brachiopods, bryozoans, and flatworms
D) Phoronids, rotifers, and bryozoans
E) Rotifers, bryozoans, and brachiopods

Question 13

Which of the following taxa does not contain wormlike organisms?

A) Nematodes
B) Clitellates
C) Annelids
D) Polychaetes
E) Bryozoans

Question 14

Many lineages of lophotrochozoans have a type of free-living larva known as a

A) polyp.
B) planula.
C) trochophore.
D) nauplius.
E) None of the above

Question 15

Nematodes are abundant and diverse because

A) they are both parasitic and free-living and eat a wide variety of foods.
B) they are able to molt their exoskeleton.
C) their thick cuticle enables them to move in complex ways.
D) their body cavity is a pseudocoelom.
E) their segmented body enables them to live in many different places.

Question 16

Insects whose hatchlings are sufficiently similar in form to adults to be recognizable are said to have

A) instars.
B) neopterous development.
C) accelerated development.
D) incomplete metamorphosis.
E) complete metamorphosis.

Question 17

Which of the following is not part of the molluscan body plan?

A) Mantle
B) Foot
C) Radula
D) Visceral mass
E) Jointed skeleton

Question 18

Nautiluses control their buoyancy by

A) adjusting salt concentrations in their blood.
B) forcibly expelling water from the mantle.
C) pumping water and gases in and out of internal chambers.
D) using the complex sensory organs in their heads.
E) swimming rapidly.

Question 19

Which of the following has not been a major feature of protostome evolution?

A) Parasitism and complex life cycles
B) Segmentation of the body cavity
C) Improved mechanisms of locomotion, including muscles (versus cilia) for body movement
D) Evolution of mechanisms for ingesting large prey
E) Evolution of hard external body parts (exoskeletons)

Question 20

Of the groups listed below, which is a descendant of the most recent common ancestor of lophotrochozoans?

A) Sponges
B) Vertebrates
C) Mollusks
D) Insects
E) Cnidarians

Question 21

Which of the following statements about bryozoans is false?

A) They are colonial.
B) They are wormlike in structure.
C) They are mainly marine.
D) They have a lophophore.
E) Individual colony members may have specialized functions.

Question 22

Which of the following taxa includes more than 10,000 species?

A) Bryozoans
B) Loriciferans
C) Flatworms
D) Rotifers
E) Monoplacophorans

Question 23

Flatworms differ from cnidarians in that flatworms

A) are radially symmetrical, whereas cnidarians are bilaterally symmetrical.
B) have more complex internal organs than cnidarians do.
C) are diploblastic, whereas cnidarians are triploblastic.
D) have two openings to the digestive cavity, whereas cnidarians have only one.
E) have an excretory system, whereas cnidarians do not.

Question 24

Which body part in a mollusk secretes the shell?

A) Mantle
B) Foot
C) Visceral mass
D) Radula
E) Spicules

Question 25

Which of the following is the most inclusive group that would include a segmented marine animal that develops through spiral cleavage and has parapodia?

A) Nematodes
B) Annelids
C) Brachiopods
D) Mollusks
E) Flatworms

Question 26

Which of the following is not associated with the rotifers?

A) A pseudocoelom
B) A complete gut
C) Conspicuous feeding organs
D) Radial symmetry
E) Movement by beating cilia

Question 27

Which of the following statements about oligochaetes is false?

A) They are hermaphroditic.
B) They have separate nerve centers called ganglia.
C) They have a segmented coelom.
D) They have serially repeated organs.
E) Their zygotes undergo radial cleavage.

Question 28

Brachiopods reached their peak abundance and diversity during the

A) Paleozoic.
B) Mesozoic.
C) Cenozoic.
D) Precambrian.
E) Both a and b

Question 29

Which of the following groups is not part of the annelid clade?

A) Bryozoans
B) Polychaetes
C) Oligochaetes
D) Clitellates
E) Leeches

Question 30

The large and remarkable pogonophoran annelids live near deep-ocean hydrothermal (volcanic) vents where food items are scarce. Many species are able to obtain enough nutrition because

A) they are able to conduct photosynthesis.
B) their tissues harbor endosymbiotic bacteria that fix carbon by oxidizing hydrogen sulfide and methane.
C) they fix carbon from the minerals found in the ocean's muddy floor.
D) they filter algae out of ocean water.
E) they feed on dead fish that sink to the ocean floor.

Question 31

Which of the following organisms are hermaphroditic?

A) Polychaetes
B) Oligochaetes
C) Squids
D) Gastropods
E) All of the above

Question 32

Flatworms are often parasitic. Which of the following is an adaptation found in flatworms that is associated with a parasitic lifestyle?

A) Large size
B) A highly branched gastrovascular cavity
C) An oxygen transport system
D) Absorption of nutrients through the body surface
E) None of the above

Question 33

Which of the following statements about the flatworms is false?

A) Some are parasitic.
B) They possess a mouth but no anus.
C) They are diploblastic.
D) They possess some degree of cephalization.
E) Some possess complex life cycles.

Question 34

Which of the features below does not describe the phoronids?

A) Fewer than 100 species
B) Active forager and carnivorous
C) Secretion of chitinous tubes
D) Possession of a lophophore
E) Length ranging from 5 to 25 cm

Question 35

The molluscan body plan includes three unique, shared, derived characteristics that support the monophyly of the group: the _______, the _______, and the _______.

A) foot; radula; mantle
B) foot; mantle; shell
C) visceral mass; radula; mantle
D) visceral mass; mantle; shell
E) foot; visceral mass; mantle

Question 36

Which of the following is not associated with a parasitic lifestyle as seen in tapeworms and flukes?

A) Complex digestive systems
B) Flattened body
C) Life cycles with several larval stages
D) Life cycles with multiple hosts
E) Reduced gastrovascular cavity

Question 37

In free-living flatworms, which of the following functions occurs by simple diffusion?

A) Respiration
B) Absorption of nutrients
C) Excretion
D) Distribution of nutrients within the body
E) All of the above

Question 38

Which of the following groups includes animals with segmented coeloms?

A) Bryozoans
B) Mollusks
C) Annelids
D) Flatworms
E) Nematodes

Question 39

Which of the following groups includes the fewest species?

A) Mollusks
B) Bryozoans
C) Arthropods
D) Nematodes
E) Lophotrochozoans

Question 40

You discover a new organism with the following characteristics: the body is wormlike and has a fluid-filled cavity, the feeding organ looks like a proboscis, and there is a complete digestive tract. The organism is probably a(n)

A) annelid.
B) flatworm.
C) nematode.
D) ribbon worm.
E) horsehair worm.

Question 41

Which of the following groups contains the largest number of species?

A) Rotifers
B) Arthropods
C) Annelids
D) Phoronids
E) Polychaetes

Question 42

Trichinella spiralis, the causative agent of the disease trichinosis, is a

A) ribbon worm.
B) flatworm.
C) nematode.
D) rotifer.
E) annelid.

Question 43

An animal with bilateral symmetry, a pseudocoelom, a tubular digestive system, and a thick, multilayer cuticle is most likely

A) an arrow worm.
B) a flatworm.
C) a nematode.
D) a polychaete.
E) an annelid.

Question 44

Which taxa have an open circulatory system, a complete digestive tract, and a reduction of the coelom?

A) Rotifers
B) Annelids
C) Mollusks
D) Nematodes
E) Flatworms

Question 45

Some cephalopods have modified their excurrent siphon and mantle to allow them to

A) ingest large prey.
B) alter their buoyancy.
C) move rapidly through the water.
D) attach to a substrate.
E) become parasitic.

Question 46

Which of the following statements concerning the mantle of mollusks is false?

A) It is present in all groups of mollusks except the octopuses.
B) In terrestrial gastropods, it is modified into a lung.
C) It is part of a filtering device used for feeding in bivalves.
D) It is used as the basis of jet propulsion by cephalopods.
E) It secretes the shell that provides external protection in most molluscan groups.

Question 47

Which of the following statements concerning nematodes is false?

A) Parasitic nematodes infect many animal species, including humans and many domestic animals.
B) Parasitic nematodes infect many crop plants.
C) No nematode species is beneficial to humans.
D) Free-living nematodes are often extremely abundant.
E) The diet of nematodes is varied.

Question 48

Organisms of which group are probably most similar to ancestral arthropods?

A) Chelicerates
B) Nematodes
C) Crustaceans
D) Onychophorans
E) Trilobites

Question 49

Which of the following ecdysozoan groups contains fewer than 100 species?

A) Copepods
B) Arthropods
C) Priapulids
D) Insects
E) Nematodes

Question 50

Which of the following groups does not have a circulatory system?

A) Nematodes
B) Chelicerates
C) Crustaceans
D) Horsehair worms
E) Both a and d

Question 51

An animal that has a hemocoel, a chitinous exo-skeleton, and a complete digestive tract would most likely be

A) a nematode.
B) an annelid.
C) an arthropod.
D) a mollusk.
E) an arrow worm.

Question 52

The centipedes and millipedes belong to which group?

A) Hexapods
B) Arachnids
C) Myriapods
D) Annelids
E) Chelicerates

Question 53

The sister group of the kinorhynchs and loriciferans are the

A) nematodes.
B) crustaceans.
C) priapulids.
D) chelicerates.
E) tardigrades.

Question 54

Nautiluses are unique among living cephalopods in that they have

A) an excurrent siphon.
B) eyes comparable to vertebrates.
C) an incurrent siphon.
D) a chambered shell.
E) All of the above

Question 55

Which of the following statements describes locomotion in nematodes?

A) Rhythmically beating cilia move the animal forward.
B) Circular and longitudinal muscles work against each other and the pseudocoelom to change the shape of the animal, moving it forward.
C) Longitudinal muscles contract.
D) A series of hairs that project backward engage the substrate; back-and-forth movements propel the animal forward.
E) Water expelled through special ducts moves the animal forward.

Question 56

Members of which of the following groups have a pseudocoel?

A) Arrow worms and horsehair worms
B) Horsehair worms and nematodes
C) Horsehair worms, nematodes, and arrow worms
D) Nematoda, chelicerates, and arrow worms
E) Horsehair worms, nematodes, and hexapods

Question 57

A lophotrochozoan with eight overlapping calcareous plates and a feeding structure called a radula belongs to which group?

A) Slugs
B) Bivalves
C) Chitons
D) Gastropods
E) Monoplacophorans

Question 58

A very small animal (about 0.3 mm in length) with fleshy, unjointed legs and living in marine sand is most likely a(n)

A) tardigrade.
B) onychophoran.
C) chelicerate.
D) crustacean.
E) hexapod.

Question 59

Some mollusks have a rasping feeding structure known as the

A) proboscis.
B) rhynchocoel.
C) radula.
D) corona.
E) mastax.

Question 60

Which of the following statements about exoskeletons is true?

A) They are a highly efficient means of anchoring muscles, thereby providing more efficient movement.
B) They provide protection from predators.
C) They must be shed for the animal to grow, and during the shedding period the animal is vulnerable to predators.
D) They provide support for walking on dry land.
E) All of the above

Question 61

Wings evolved _______ in protostomes.

A) once
B) twice
C) three times
D) four times
E) many times, independently

Question 62

The wingless insects belong to which of the following groups?

A) Apterygotes
B) Pterygotes
C) Myriapods
D) Arachnids
E) Chelicerates

Question 63

Which of the following statements concerning the tracheal system in insects is false?

A) Tracheae are air sacs and tubular channels.
B) Tracheae penetrate virtually every part of an insect's body.
C) Tracheae extend through a single tube to an insect's mouth.
D) Tracheae provide oxygen to the insects' tissues.
E) Tracheae extend from external openings inward to tissues throughout the body.

Question 64

Which of the following statements about insect wings is false?

A) The insect wing may have evolved from an ancestral appendage similar to that of modern crustaceans.
B) Development of the insect wing is governed by the expression of the same gene that governs the crayfish appendage.
C) Development of the insect wing and development of the crayfish appendage are controlled by the pdm gene.
D) The pdm gene is expressed in both the wings and legs of insects.
E) Appendages of ancestral crustaceans and wings of ancestral insects expressed the same gene (pdm).

Question 65

Flatworms, nematodes, rotifers, annelids, and arthropods all display _______ symmetry.

Question 66

Which one of the following arthropod groups includes the dragonflies?

A) Myriapods
B) Trilobites
C) Chelicerates
D) Crustaceans
E) Hexapods

Question 67

Butterflies belong to which order of winged insects?

A) Lepidoptera
B) Coleoptera
C) Diptera
D) Trichoptera
E) Isoptera

Question 68

Which of the following groups of crustaceans bears a superficial resemblance to mollusks?

A) Barnacles
B) Copepods
C) Isopods
D) Decapods
E) Water fleas

Question 69

Which of the following are so numerous that they are thought to be the most abundant of all marine arthropods?

A) Crustaceans
B) Millipedes
C) Nematomorphs
D) Barnacles
E) Apterygotes

Question 70

Which of the following is not one of the major recognized groups of winged insects?

A) Insects that cannot fold their wings back against the body
B) Insects that can fold their wings and undergo incomplete metamorphosis
C) Insects that do not undergo metamorphosis
D) Insects that can fold their wings and undergo complete metamorphosis
E) All of the above are major recognized groups.

Question 71

A typical crustacean larva is called a

A) trochophore.
B) nauplius.
C) planula.
D) pupa.
E) caterpillar.

Question 72

Which of the following statements about spider webs and threads is false?

A) The webs can function as a home.
B) The threads are produced by modified abdominal appendages connected to internal secretory glands.
C) The threads are composed primarily of carbohydrates.
D) The webs function as a snare for catching prey.
E) The threads provide safety lines for climbing.

Question 73

The _______ have bodies that are divided into two parts: a head region that bears two pairs of appendages modified to form mouthparts, and a trunk region with typically four pairs of walking legs.

A) chelicerates
B) crustaceans
C) hexapods
D) nematodes
E) myriapods

Question 74

Which group of arthropods flourished in the Cambrian and Ordovician but went extinct about 251 mya?

A) Onchyphorans
B) Tardigrades
C) Trilobites
D) Myriapods
E) Chelicerates

Question 75

Some lophotrochozoans have a circular or U-shaped ring of tentacles around the mouth called a _______.

Question 76

The most diverse (specious) group of insects consists of the

A) grasshoppers and crickets.
B) ants, bees, and wasps.
C) lice.
D) beetles.
E) thrips.

Question 77

_______ can survive for at least 10 years in a dormant, dehydrated state.

A) Myriapods
B) Onychophorans
C) Pycnogonids
D) Tardigrades
E) Trilobites

Question 78

Insects are different from other hexapods in that they possess

A) a pair of antennae.
B) a motion-sensitive receptor called Johnston's organ.
C) a dorsal nerve cord.
D) six pairs of appendages.
E) an exoskeleton.

Question 79

The diversification of insects about 450 million years ago corresponds with

A) the appearance of the first land plants.
B) the evolution of cartilaginous fish.
C) the extinction of dinosaurs.
D) changes in the CO₂ concentration of the atmosphere.
E) None of the above

Question 80

Which of the following is not a characteristic of most insect species?

A) The ability to fly
B) Three basic body segments
C) A complex respiratory system, including lungs
D) Excretory organs
E) A digestive system