CHAPTER 31—ANIMAL PHYLOGENY, ACOELOMATES, AND PROTOSTOMES
MULTIPLE CHOICE
1. The Burgess Shale formation in western Canada, with fossils dating to about ____ years ago, includes
a wide variety of animal fossils such as Hallucingenia and Opabinia.
a.
4 billion
b.
8,000
c.
530 million
d.
1.2 billion
e.
78 million
2. Zoologists have described nearly ____ living species of animals.
a.
20,000
b.
2 million
c.
47,000
d.
100,000
e.
1 million
3. Which of the following statements about Kingdom Animalia is/are FALSE?
a.
Diversification of animals is due in large part to motility.
b.
Diversification of animals is due in large part to predator prey interactions.
c.
Diversification of animals is marked by the evolution of specialized tissues and organ
systems as well as complex behaviors.
d.
Vertebrates encompass only a small fraction of total animal diversity.
e.
All of these are true statements.
4. Which of the following statements about kingdom Animalia is FALSE?
a.
All adult animals are motile.
b.
All animals are eukaryotes.
c.
All adult animals are multicellular.
d.
Animal cells lack cell walls.
e.
All animals are heterotrophs.
5. An organism that is unable to move on its own power is said to be
a.
sessile.
b.
a zygote.
c.
sedentary.
d.
a larva.
e.
a gamete.
6. Which of the following is NOT a line of evidence that Kingdom Animalia is a monophyletic group?
a.
The ribosomal RNA of animals is more similar to that of other animals than it is to any
other form of life.
b.
Animals share unique similarities in their cell-to-cell junctions.
c.
All animals have the same genetic code.
d.
Animals share similarities in the molecules in their extracellular matrices.
e.
All animals have bilateral symmetry.
7. Most biologists agree that the most recent common ancestor of all animals was probably a ____, an
idea first proposed by Ernst Haeckel in 1874.
a.
jellyfish
b.
ciliated protozoan
c.
sessile sponge
d.
chytrid
e.
colonial, flagellated protist
8. Groups of cells that share a common structure and function are considered to be
a.
organs.
b.
mesenteries.
c.
colonies.
d.
tissues.
e.
organ systems.
9. In most eumetazoans the innermost tissue layer during development is the
a.
mesoderm.
b.
epiderm.
c.
mesoglea.
d.
endoderm.
e.
ectoderm.
10. In most eumetazoans the outermost tissue layer during development is the
a.
mesoderm.
b.
epiderm.
c.
mesoglea.
d.
endoderm.
e.
ectoderm.
11. In most eumetazoans the middle tissue layer during development is the
a.
mesoderm.
b.
epiderm.
c.
mesoglea.
d.
endoderm.
e.
ectoderm.
12. Which embryonic cell layer develops into the lining of the gut in most eumetazoans?
a.
mesoderm
b.
epiderm
c.
mesoglea
d.
endoderm
e.
ectoderm
13. The nervous system is derived mainly from which embryonic cell layer in most eumetazoans?
a.
mesoderm
b.
epiderm
c.
mesoglea
d.
endoderm
e.
ectoderm
14. The muscles of the body wall are derived mainly from which embryonic cell layer in most
eumetazoans?
a.
mesoderm
b.
epiderm
c.
mesoglea
d.
endoderm
e.
ectoderm
15. Members of the phylum ____ exhibit radial symmetry, with their body parts arranged regularly around
a central axis.
a.
Porifera
b.
Mollusca
c.
Cnidaria
d.
Platyhelminthes
e.
Chordata
16. Animals that do not have a body cavity that separates the gut from the muscles of the body wall are
said to be
a.
pseudocoelomate.
b.
mesenteries.
c.
acoelomate.
d.
indeterminate.
e.
coelomate.
17. Animals that have a fluid-filled cavity that separates the gut from the muscles of the body wall and
have that cavity completely lined by the peritoneum are said to be
a.
pseudocoelomate.
b.
mesenteries.
c.
acoelomate.
d.
indeterminate.
e.
coelomate.
18. Which of the following is found most often for protostomes?
a.
spiral, indeterminate cleavage
b.
radial, indeterminate cleavage
c.
spiral, determinate cleavage
d.
radial, determinate cleavage
e.
radial cleavage in juveniles, determinant cleavage in adults
19. Which of the following is found most often for deuterostomes?
a.
spiral, indeterminate cleavage
b.
radial, indeterminate cleavage
c.
spiral, determinate cleavage
d.
radial, determinate cleavage
e.
radial cleavage in juveniles, determinant cleavage in adults
20. The ____ is the initial opening between the developing gut and the outside environment for most
animal embryos.
a.
schizocoelom
b.
mesoglea
c.
archenteron
d.
enterocoelom
e.
blastopore
21. The ____ is the developing gut for most animal embryos.
a.
schizocoelom
b.
mesoglea
c.
archenteron
d.
enterocoelom
e.
blastopore
22. The ____ is the developmental origin of the body cavity between the gut and muscles of the body wall
for most protostomes.
a.
schizocoelom
b.
mesoglea
c.
archenteron
d.
enterocoelom
e.
blastopore
23. Ringlike patterns on an earthworm and “six-pack abs” in humans are evidence of ____ in an animal’s
body plan.
a.
cephalization
b.
segmentation
c.
radial symmetry
d.
mesenteries
e.
cleavage
24. Which of the following statements about the advantages of segmentation is FALSE?
a.
Each segment in an animal may include a complete set of organs.
b.
Segmentation allows for flexibility in movement.
c.
Segmentation allows for control over movement.
d.
Segmentation allows for the animal to have a body cavity.
e.
A segmented animal may survive damage to organs in one segment because of redundancy
in another segment.
25. Based on molecular analysis, which of the following appears to be least meaningful for inferring
animal phylogenic relationships?
a.
presence or absence of tissues
b.
mitochondrial DNA sequences
c.
radial symmetry in the Radiata
d.
body cavity differences
e.
Hox gene sequences
26. Which animal taxon is named for the cuticle or external skeleton that its members secrete and
periodically molt?
a.
Deuterostomia
b.
Ecdysozoa
c.
Reptilia
d.
Lophotrochozoa
e.
Protostomia
27. Based on modern molecular phylogeny, which of the following is a derived condition within
Lophotrochozoa?
a.
acoelomate species
b.
bilateral symmetry
c.
tissues
d.
multicellularity
e.
schizocoelom
28. Based on modern molecular phylogeny, which of the following animal taxons does NOT have any
members with segmentation as a derived condition?
a.
Deuterostomia
b.
Ecdysozoa
c.
Lophotrochozoa
d.
Protostomia
e.
Radiata
29. Many sponges are hermaphroditic, which means that
a.
both males and females are filter feeders.
b.
both males and females produce sperm.
c.
a single individual produces both sperm and eggs.
d.
only males have flagellae.
e.
both males and females produce gemmules.
30. Which of the following phyla is a member of the Parazoa?
a.
Nemertea
b.
Porifera
c.
Rotifera
d.
Ctenophora
e.
Echinodermata
31. Asymmetry, choanocytes, filter feeding, osculum, and spicules are all terms associated with which
phylum?
a.
Nematoda
b.
Ctenophora
c.
Nemertea
d.
Porifera
e.
Cnidaria
32. The beating flagellae of ____ maintain a constant flow of water through sponges.
a.
amoeboid cells
b.
choanocytes
c.
sperm
d.
porocytes
e.
pinacoderm
33. Spicules are secreted by
a.
amoeboid cells.
b.
choanocytes.
c.
sperm.
d.
porocytes.
e.
pinacoderm.
34. Spicules are ____ that are found in sponges.
a.
fibrous skeletal proteins
b.
specialized digestive cells
c.
complicated pore openings and passageways
d.
needlelike skeletal structures made up of silica or calcium carbonate
e.
feeding cells with a flagellum surrounded by a collar
35. Which of the following phyla is a member of the Radiata?
a.
Nemertea
b.
Porifera
c.
Rotifera
d.
Ctenophora
e.
Echinodermata
36. Members of this phylum have radial symmetry and nematocysts; they may have polyp or medusa
forms (or both) as adults.
a.
Nematoda
b.
Cnidaria
c.
Porifera
d.
Rotifera
e.
Ctenophora
37. Like other members of their phylum, jellyfishes have specialized stinging cells called ____ as part of
their epidermis, which they use to paralyze small prey.
a.
choanocytes
b.
polyps
c.
cnidocytes
d.
flame cells
e.
tentacles
38. Most members of this lineage of Cnidarians have both polyp and medusa stages in their life cycles,
with the polyp stage typically forming a colony. Species of Obelia are members of this lineage.
a.
Hydrozoa
b.
Scyphozoa
c.
Trematoda
d.
Cubozoa
e.
Anthozoa
39. Adult members of this lineage of Cnidarians are predominately medusae. They are the true jellyfishes,
and are not active swimmers.
a.
Hydrozoa
b.
Scyphozoa
c.
Trematoda
d.
Cubozoa
e.
Anthozoa
40. Members of this lineage of Cnidarians exist primarily as cube-shaped medusae. They are active
swimmers, and they produce one of the deadliest toxins made by animals.
a.
Hydrozoa
b.
Scyphozoa
c.
Trematoda
d.
Cubozoa
e.
Anthozoa
41. The members of this lineage of Cnidarians exist only as polyps as adults. Many build calcium
carbonate exoskeletons and have a mutualistic relationship with photosynthetic protists.
a.
Hydrozoa
b.
Scyphozoa
c.
Trematoda
d.
Cubozoa
e.
Anthozoa
42. Members of this phylum have radial symmetry, and use their two tentacles to capture prey. They have
eight longitudinal plates of cilia that they use for movement, making them the largest animals to use
cilia as their primary means of locomotion.
a.
Nematoda
b.
Cnidaria
c.
Porifera
d.
Rotifera
e.
Ctenophora
43. Members of the phyla Ectoprocta, Brachipoda, and Phoronida all possess a lophophore, which is
a.
a cluster of pores along the aboral surface, used for expelling wastes from the digestive
tract.
b.
a hard shell made of calcium carbonate.
c.
an outpocket of the digestive tract, where metabolic wastes are processed before emptying
into the digestive tract for expulsion.
d.
a circular fold with one or two rows of hollow, ciliated tentacles.
e.
an extra body cavity surrounding the digestive tract filled with muscles used for
locomotion.
44. Members of this Lophotrochozoan phylum are acoelomate and dorsoventrally flattened. They do not
have circulatory or respiratory systems.
a.
Rotifera
b.
Mollusca
c.
Platyhelminthes
d.
Annelida
e.
Nemertea
45. Flatworms have specialized cells called ____ that serve as a simple excretory system.
a.
choanocytes
b.
polyps
c.
cnidocytes
d.
flame cells
e.
tentacles
46. Members of this lineage of flatworms are free-living and are found mostly in marine environments.
Most acquire food with a muscular pharynx and are hermaphroditic.
a.
Trematoda
b.
Turbellaria
c.
Polychaeta
d.
Cestoda
e.
Hirudinea
47. Members of this lineage of flatworms are parasites of vertebrates. They have a head modified into a
scolex with hooks and suckers for attaching to places like the intestinal wall of hosts. Most of their
body is a series of reproductive units called proglottids.
a.
Trematoda
b.
Turbellaria
c.
Polychaeta
d.
Cestoda
e.
Hirudinea
48. Found mostly in freshwater, members of this Lophotrochozoan phylum have a wheel-like, ciliated
food-gathering organ around their head called a corona. Some members of this phylum make extensive
use of parthenogenesis for reproduction.
a.
Rotifera
b.
Mollusca
c.
Platyhelminthes
d.
Annelida
e.
Nemertea
49. Found mostly in marine environments, members of this Lophotrochozoan phylum are called ribbon
worms or proboscis worms. They have a muscular, mucus-covered tube that they can turn inside out to
capture prey.
a.
Rotifera
b.
Mollusca
c.
Platyhelminthes
d.
Annelida
e.
Nemertea
50. This is the Lophotrochozoan phylum with the most species, having about 100,000 described living
species.
a.
Rotifera
b.
Mollusca
c.
Platyhelminthes
d.
Annelida
e.
Nemertea
51. Species in this Lophotrochozoan phylum have a body divided into three regions: visceral mass, head-
foot, and mantle.
a.
Rotifera
b.
Mollusca
c.
Platyhelminthes
d.
Annelida
e.
Nemertea
52. Polyplacophora, Gastropoda, Bivalvia, and Cephalopoda are all lineages within the phylum
a.
Rotifera.
b.
Mollusca.
c.
Platyhelminthes.
d.
Annelida.
e.
Nemertea.