1
Campbell Biology: Concepts and Connections, 8e (Reece et al.)
Chapter 18 The Evolution of Invertebrate Diversity
18.1 Multiple-Choice Questions
1) All animals
A) are prokaryotic.
B) are heterotrophic.
C) have cell walls made of chitin.
D) obtain food by absorption.
2) Typical animal embryos have ________, or external cell layer, and ________, which lines the
digestive tract.
A) an ectoderm; a blastula
B) an ectoderm; an endoderm
C) an endoderm; an ectoderm
D) a mesoderm; a gastrula
3) Which of the following statements is true of a typical animal?
A) Homeotic genes play important roles in the development of the organism from zygote to
adult.
B) The organism requires carbon dioxide as an essential nutrient.
C) The cell walls are diverse in structure but are composed of chitin.
D) The haploid larvae develop into diploid adults.
4) Animals directly evolved from
A) plants.
B) protists.
C) fungi.
D) bacteria.
5) During the Cambrian explosion approximately 535 to 525 million years ago,
A) all modern species of animals suddenly appeared.
B) animals rapidly diversified in the oceans.
C) a massive volcanic eruption nearly wiped out life on Earth.
D) great forests produced peat layers that were later transformed into coal.
6) Which of the following is considered a likely explanation for the events of the Cambrian
explosion?
A) Complex predator-prey relationships and increased atmospheric oxygen levels promoted
animal diversification.
B) A great surge of volcanic activity was triggered by significant movements of the continental
plates and possibly by an asteroid impact.
C) Solar flares led to increased UV radiation intensity, which in turn promoted a high rate of
mutation. This led to rapid diversification of animals.
D) The massive growth of swamp vegetation depleted the atmosphere’s carbon dioxide and
eventually cooled the Earth’s climate.
7) Most of the animals alive today
A) are vertebrates.
B) are invertebrates.
C) are choanoflagellates.
D) are really colonies of protist cells.
8) Which of the following animals displays radial symmetry?
A) a worm
B) a sea anemone
C) a fish
D) a lobster
9) Which of the following items demonstrates radial symmetry?
A) a glove
B) a tennis racket
C) a pair of sunglasses
D) an apple pie
10) Organisms with true radial symmetry
A) have their sense organs, mouth, and brain clustered in the head.
B) tend to be highly mobile.
C) do not have a distinct head region and tend to be sedentary or passive drifters.
D) can be divided into two matching halves along only one plane.
11) Which of the following statements is true?
A) Arthropods have an open circulatory system, while annelids have a closed circulatory system.
B) Vertebrates have an open circulatory system, while annelids have a closed circulatory system.
C) Vertebrates have an open circulatory system, while arthropods have a closed circulatory
system.
D) Annelids have an open circulatory system, while molluscs have a closed circulatory system.
12) The locomotive behavior of earthworms is enabled by contraction of their longitudinal and
circular muscles; this is seen through their typical burrowing behavior. Nematodes, however,
contract their longitudinal muscles against the pressure of fluid in their bodies to produce a
whiplike motion that enables them to move. Suppose you place an earthworm and a nematode in
a watery solution. Which do you think would be able to move more easily, and why?
A) the earthworm, because it uses two sets of muscles to help it move through the watery
solution
B) the nematode, because its whiplike motion will easily propel it through the watery solution
C) the earthworm, because it can contract and expand its muscles to burrow down through the
watery solution
D) the nematode, because it can move its paddle-like appendages on its segments to help it move
through the watery solution
13) A dog’s head is at its ________ end, and its belly is its ________ surface.
A) posterior; dorsal
B) anterior; dorsal
C) posterior; ventral
D) anterior; ventral
14) In protostomes,
A) the opening formed during gastrulation becomes the mouth.
B) the opening formed during gastrulation becomes the anus.
C) there is no body cavity.
D) there is no endoderm.
15) Which of the following statements about deuterostomes is true?
A) Deuterostomes lack true tissues.
B) Deuterostomes have only two tissue layers.
C) The opening that forms during deuterostome gastrulation becomes the anus.
D) The opening that forms during deuterostome gastrulation becomes the mouth.
16) Which of the following are not included among the eumetazoans that have true tissues?
A) sea stars (Echinodermata)
B) earthworms (Annelida)
C) sea anemones (Cnidaria)
D) sponges (Porifera)
17) Which of the following are not included among the bilateria, a clade of animals with bilateral
symmetry at some stage of development?
A) sea stars (Echinodermata)
B) earthworms (Annelida)
C) sea anemones (Cnidaria)
D) octopus (Mollusca)
18) The ________ is a flagellated cell that sweeps water through a sponge’s body.
A) choanocyte
B) amoebocyte
C) spicule
D) spongin
19) A typical sponge is best described as
A) a slow-moving suspension feeder with a true coelom.
B) a sessile suspension feeder with bilateral symmetry.
C) a slow-moving carnivore with no true tissues or symmetry.
D) a sessile suspension feeder with no true tissues or body symmetry.
20) How do sponges transport nutrients within their bodies?
A) They have simple digestive and circulatory systems composed of spongin.
B) They rely on diffusion to move nutrients between their cells.
C) Their mobile amoebocytes transport food molecules from cell to cell.
D) They are not able to transport nutrients within their bodies but must independently absorb all
necessary nutrients from the surrounding water.
21) Which of the following statements regarding cnidarians is true?
A) Cnidarians have three true tissue layers.
B) The digestive and circulatory compartment of cnidarians is called the gastrovascular cavity.
C) The more stationary cnidarian body form, which is cylindrical with a ring of tentacles, is the
medusa.
D) Cnidarians are herbivores and can be destructive grazers on seaweeds.
22) Coral reefs are
A) shells of Mollusca that have been converted to rock by geological processes.
B) hard external skeletons secreted by coral animals (Cnidaria).
C) marine rocks that often are used as attachment places by Cnidaria.
D) hardened sugars that are secreted by algae.
7
23) While wading in the ocean, you look down into the water and notice an umbrella-shaped,
translucent animal. It swims by pulsing its body, and long tentacles trail behind it. One of them
brushes your leg. Ouch! You feel a burning sensation where it touched you. To what phylum
does this creature probably belong?
A) Porifera
B) Cnidaria
C) Platyhelminthes
D) Mollusca
24) Flatworms (Platyhelminthes) are ________ and typically have ________.
A) radially symmetrical; no digestive system
B) bilaterally symmetrical; a gastrovascular cavity with one opening
C) bilaterally symmetrical; a complete digestive tract with a mouth and anus
D) all parasites; no digestive system
25) Tapeworms are similar to fungi in that
A) they have cell walls made of chitin.
B) they are sessile autotrophs.
C) they feed by absorption.
D) they inhabit marine, damp terrestrial, and freshwater habitats.
26) A bilaterally symmetrical, wormlike animal that has a complete digestive tract and a cuticle
could be a member of which of the following phyla?
A) Cnidaria
B) Annelida
C) Nematoda
D) Chordata
27) The digestive tract of a nematode is most like which of the following?
A) a sock
B) a soda straw
C) a cup
D) a baseball
28) Which of the following is a typical characteristic of molluscs?
A) a gastrovascular cavity with only one opening
B) a sessile lifestyle
C) an internal skeleton and segmented body plan
D) a rasping organ called the radula
29) Which mollusc group includes primarily sedentary animals that use mucus-coated gills to
trap fine food particles?
A) cephalopods
B) gastropods
C) chitons
D) bivalves
30) You inflate a balloon and let it go. It shoots away as air exits forcefully through the balloon’s
narrow opening. This most closely resembles the mode of movement seen in
A) sea anemones.
B) snails.
C) squid.
D) nematodes.
9
31) Which adaptation is a key characteristic of annelids that greatly increases their flexibility and
mobility?
A) complete digestive tract
B) exoskeleton
C) segmentation
D) three true tissue layers
32) ________ are soil-dwellers; ________ are mostly marine; and ________ mostly inhabit fresh
water.
A) Earthworms; leeches; annelids
B) Earthworms; leeches; polychaetes
C) Earthworms; polychaetes; leeches
D) Polychaetes; earthworms; leeches
33) You find a wormlike, soft-bodied adult animal in a mudflat. It is bilaterally symmetrical, is
segmented, has a true coelom, and has a complete digestive tract. Based on these characteristics,
what phylum does the animal represent?
A) Cnidaria
B) Platyhelminthes
C) Nematoda
D) Annelida
34) Animals that are segmented and have jointed appendages and an exoskeleton are members of
the phylum
A) Platyhelminthes.
B) Annelida.
C) Cnidaria.
D) Arthropoda.
35) The most numerous, diverse, and widespread animals are the
A) Arthropoda.
B) Mollusca.
C) Annelida.
D) Chordata.
36) While walking in your basement, you hear a crunching noise and notice that you have
stepped on an organism. You look closely and see part of a segmented body and a few jointed
appendages. What phylum does this animal represent?
A) Echinodermata
B) Annelida
C) Arthropoda
D) Chordata
37) Which of the following groups has a series of similar segments that make up most of the
body?
A) millipedes
B) crustaceans
C) scorpions
D) insects
38) Which of the following groups includes both spiders and horseshoe crabs?
A) millipedes
B) crustaceans
C) chelicerates
D) insects
39) Most adult insects have three major body parts or sections. They are the
A) head, body, and legs.
B) head, thorax, and abdomen.
C) antennae, head, and abdomen.
D) legs, wings, and body.
40) An organism that can fly and has an exoskeleton must be
A) a member of the Chordata.
B) an echinoderm.
C) an insect.
D) a polychaete.
41) The traits that are unique to insects and have probably contributed to their diversity and
success include
A) small body size, an exoskeleton, and sexual reproduction.
B) flight, short generation times, and complex life cycles including complete metamorphosis.
C) the exoskeleton, an open circulatory system, and jointed appendages.
D) the presence of four or more pairs of legs, an exoskeleton, and a water-resistant cuticle.
42) Complete metamorphosis is considered to occur in a species
A) if the larva and adult have different diets.
B) if the larva and adult live in different habitats.
C) if a pupation stage separates the larval and adult stages.
D) if the adult has wings, but the larva does not.
43) The insect body plan includes many groups of serially repeated units. For example, there are
typically three pairs of legs, one on each of the three segments of the thorax. Which of the
following options best describes how these pairs of legs develop and evolve?
A) A single gene controls the development of all six legs. Thus within a species, all three pairs of
legs are identical.
B) The leg pairs all influence each other during development. Gene products move by diffusion
from one segment to the other. Therefore, it is impossible to alter the development and form of
one pair of legs without causing similar changes in the other two pairs of legs.
C) The body parts develop in a modular fashion. Therefore, a genetic change could alter the
development of one pair of limbs without noticeably changing the rest of the insect’s body plan.
D) The leg pairs grow under the control of an ancient set of highly conserved genes. Therefore,
all insects have more or less identical legs. Other parts of the insect body plan can evolve
somewhat more freely.
44) The symmetry of echinoderms generally includes
A) radially symmetrical larvae and adults.
B) bilaterally symmetrical larvae and adults.
C) bilaterally symmetrical larvae and radially symmetrical adults.
D) radially symmetrical larvae and bilaterally symmetrical adults.
45) Which of the following is a unique feature of echinoderms?
A) bilateral symmetry
B) a water vascular system
C) radial symmetry
D) a deuterostome pattern of development