Chapter 32 Quiz: An Introduction to Animal Diversity
1. A body plan is:
a) a path in which zoologists use organize species into separate phylogenetic trees
b) a classification of animal species that share the same level of organizational complexity
c) the set of morphological and developmental traits that classify a grade
d) a map that outlines the path of closely related animals
e) an analysis of a ancestral patterns of a group of species under the same clade
2. Most animals undergo cleavage to form a:
a) blastocoel
b) blastula
c) coelom
d) gastrula
e) zygote
3. Which of the following hypotheses about the Cambrian explosion is false?
a) The evolution of the Hox gene provided the developmental flexibility that resulted in
morphological variations.
b) Predators acquired new forms of locomotion that helped catch prey, while prey adapted
new defence mechanisms
c) An increase in CO2 provided plants and other organisms to take new forms and undergo
diversification
d) An increase in O2 favoured animals with higher metabolic rates and larger body size
e) none of the above
4. Cephalization is:
a) a process that occurs with radial symmetrical animals
b) the developmental stage that transforms a larva into its adult form
c) the formation of concentric germ layers and various tissues in the embryo
d) the formation of the body cavity when the mesoderm buds from the wall of the archenteron
in deuterostomes
e) an evolutionary trend in which the concentration of sensory equipment are at one end of an
organism
5. _____________________ are triploblastic animals that have a fully functional body cavity formed from
the blastocoel.
a) Coelomates
b) Pseudocoelomates
c) Acoelomates
d) Anchenteron
e) Acoelopseudomates
6. Possessing a coelom is advantageous because it:
a) provides specialized nutrients to the body
b) is vital to the lining of the digestive tract and archenteron
c) allows triploblastic animals to develop the third embryonic germ layer
d) enables internal organs to develop and move independently of the outer body wall
e) all of the above
7. A type of development in which the anus develops from the blastopore and the mouth forms from
a secondary opening and is characterized by radial, indeterminate cleavage.
a) deuterostome development
b) protostome development
c) schizocoelous development
d) a) and c)
e) none of the above
8. Identical twins are possible because of which of the following:
a) Radial cleavage
b) Spiral cleavage
c) Determinate cleavage
d) Mediate cleavage
e) Indeterminate cleavage
9. Which of the following is not a characteristic of protostomes?
a) the blastopore forms from the mouth
b) Spiral cleavage
c) Enterocoelous development
d) has two taxa: ecdysozoans and the lophotrochozoans
e) b) and d)
10. Which of the following is not a points of agreement between the two phylogenetic trees:
a) Both trees show that the animal kingdom represents the Metazoa clade. If one traced all
extant lineages to their origin, the animal lineages would converge on a common ancestor.
b) Most animals belong to the clade "Radiata", and the Cambrian explosion increased the
diversification of Radiatians.
c) The deuterostome clade includes vertebrates and some other phyla.
d) All animals except sponges belong in eumetazoa and the members of this clade acquire true
tissues.
e) Sponges are under the Porifera phylum and are basal animals that exhibit a parazoan grade
of organization.
Answers:
1. C
2. B
3. C
4. E
5. B
6. D
7. A
8. E
9. C
10. B
Short Answer:
Compare and contrast the differences between protostomes and deuterostomes
Protostomes
 undergo spiral cleavage and determinate
cleavage
 the fate of the blastopore: the
blastopore becomes the mouth and an
opposite opening of the gastrula
becomes the anus
 forms a coelom through schizocoelous
development
 there are more protostome species than
deuterostomes
 Examples: insects, earthworms, and
clams
Deuterostomes
 undergo radial cleavage and
indeterminate cleavage
 the fate of the blastopore: the
blastopore becomes the anus and the
mouth forms from a secondary opening
 forms a coelom through enterocoelous
development
 Examples: humans, snakes, and sea
urchins