Many young animals are _____, a sexually immature form that is morphologically distinct from the adult stage. These young animals undergo _____ to become _____, which resemble adults but are not yet sexually mature.
A)larvae; metamorphosis; juveniles
B)larvae; metamorphosis; adults
C)juvenile; metamorphosis; adults
D)juvenile; gastrulation; adults
E)larvae; gastrulation; juveniles

A)larvae; metamorphosis; juveniles

Which of the following correctly lists the embryonic stages in the order that they develop?
A)zygote, blastula, gastrula, larva
B)blastula, zygote, gastrula, larva
C)zygote, larva, gastrula, blastula
D)zygote, gastrula, blastula, larva
E)zygote, blastula, larva, gastrula

A)zygote, blastula, gastrula, larva

Which example below is a current hypothesis regarding the Cambrian explosion?
A)An increase in atmospheric CO2 led to an explosion of plants and life-forms that fed on plants.
B)Predator-prey relationships decreased diversity through natural selection.
C)A rise in atmospheric nitrogen led to success of large animals with higher metabolic rates.
D)Evolution of the Hox gene complex provided developmental flexibility.
E)all of the above

D)Evolution of the Hox gene complex provided developmental flexibility.

Which of the following occurred during the Mesozoic era?
A)Marine reptiles disappeared.
B)Large mammalian herbivores and carnivores arose.
C)Flight evolved in pterosaurs and birds.
D)Fishes emerged as top predators in marine food webs.
E)A great diversity of new body plans emerged among animals.

C)Flight evolved in pterosaurs and birds.

Symmetry is one of the most basic characteristics of animals. The group that has a different symmetry from the other four groups listed here is the _____.
A)arthropods
B)chordates
C)molluscs
D)jellies
E)annelids

D)jellies

Which of the following is associated with bilateral symmetry?
A)a sessile lifestyle
B)a lack of true tissues
C)sponges
D)no mesoderm
E)cephalization

E)cephalization

"Cephalization" refers to having _____.
A)radial symmetry
B)a right and a left side
C)a head
D)a dorsal and a ventral surface
E)ectoderm

C)a head

Unlike other animals, sponges _____.
A)are unicellular
B)possess cell walls
C)lack true tissues
D)exhibit bilateral symmetry
E)are prokaryotic

C)lack true tissues

Which of the following is a characteristic of cnidarians?
A)triploblastic bodies
B)mesoderm
C)ectoderm and endoderm
D)a lack of true tissues
E)bilateral symmetry

C)ectoderm and endoderm

In the embryo of shark, ectoderm gives rise to _____; mesoderm gives rise to _____; endoderm gives rise to _____.
A)muscle; the outer covering of the animal; the central nervous system
B)the lining of the digestive tract; muscle; the outer covering of the animal
C)the central nervous system; the outer covering of the animal; the lining of the digestive tube
D)muscle; the outer covering of the animal; the lining of the digestive tube
E)the central nervous system; muscle; the lining of the digestive tube

E)the central nervous system; muscle; the lining of the digestive tube

All animals with bilateral symmetry have _____ germ layer(s).
A)one
B)two
C)three
D)four

C)three

A true coelom is _____.
A)a body cavity lined with tissues derived from the endoderm
B)a body cavity lined with endoderm and mesoderm
C)a body cavity lined with mesoderm
D)a thoracic body cavity
E)an abdominal body cavity

C)a body cavity lined with mesoderm

One of the primary developmental/anatomical characteristics distinguishing the major animal phyla is the condition of the body cavity. A pseudocoelomate animal is one in which the body cavity is _____.
A)bounded completely by mesoderm
B)filled by a solid mass of mesoderm
C)bounded completely by endoderm
D)bounded partly by ectoderm
E)formed from mesoderm and endoderm

E)formed from mesoderm and endoderm

The presence of a coelom is advantageous because _____.
A)it allows for a third embryonic germ layer
B)it permits the development of an open circulatory system
C)it allows room for the development and movement of internal organs
D)it is necessary for a complete digestive tract
E)all of the above

C)it allows room for the development and movement of internal organs

Indeterminate cleavage is a process that produces embryonic cells that _____.
A)retain the capacity to develop into a complete embryo
B)form eggs or sperm
C)engage in photosynthesis
D)form ectoderm but not endoderm or mesoderm
E)form mesoderm but not endoderm or ectoderm

A)retain the capacity to develop into a complete embryo

The zygotes of many protostomes undergo _____ cleavage and _____ cleavage.
A)spiral; radial
B)determinate; indeterminate
C)radial; indeterminate
D)radial; determinate
E)determinate; spiral

E)determinate; spiral

An animal with a true coelom that has _____ cleavage must be a _____.
A)radial; protostome
B)radial; deuterostome
C)spiral; deuterostome
D)spiral; endostome
E)all of the above

B)radial; deuterostome

Which of the following is a trait shared by protostomes and deuterostomes?
A)a body cavity
B)spiral cleavage
C)determinate cleavage
D)radial cleavage
E)indeterminate cleavage

A)a body cavity

Which one of the following is characteristic of protostomes?
A)The blastopore forms the anus.
B)Ectoderm forms the muscles.
C)The digestive tract is incomplete.
D)Cell fate is determined early during embryonic development.
E)Mesoderm forms appendages.

D)Cell fate is determined early during embryonic development.

The text describes two phylogenetic hypotheses regarding the relationships of the animal phyla. The tree that is based on molecular evidence differs from the tree based on morphological evidence in that it _____.
A)depicts sponges as basal animals
B)depicts cnidarians as basal eumetazoans
C)suggests that the animal clade is polyphyletic
D)divides protostomes into two taxa
E)all of the above

D)divides protostomes into two taxa

Which of the following is the defining characteristic of the clade Ecdysozoa for which this group is named?
A)a horseshoe-shaped crown of ciliated tentacles
B)a trochophore larva
C)the secretion of stiff external skeletons that must be shed to permit growth
D)segmented bodies
E)lack of true tissues

C)the secretion of stiff external skeletons that must be shed to permit growth