Test 3 testbank Flashcards
Which of the following terms or structures is properly associated only with animals?
Hox genes
The number of legs an insect has, the number of vertebrae in a vertebral column, or the
number of joints in a digit (such as a finger) are all strongly influenced by
Hox genes.
The last common ancestor of all animals was probably a
E) flagellated protist.
Almost all of the major animal body plans seen today appeared in the fossil record over 500
million years ago at the beginning of the
A) Cambrian period.
Which statement is most consistent with the hypothesis that the Cambrian explosion was
caused by the rise of predator-prey relationships?
E) increased incidence of hard parts in the fossil record
Which of the following was the least likely factor causing the Cambrian explosion?
C) the movement of animals onto land
11) Evidence of which structure or characteristic would be most surprising to find among
fossils of the Ediacaran fauna?
B) hard parts
Which of these genetic processes may be most helpful in accounting for the Cambrian
D) gene duplication
Organisms showing radial symmetry would likely
C) move from place to place relatively slowly, if at all.
During metamorphosis, echinoderms undergo a transformation from motile larvae to a
sedentary (or sometimes sessile) existence as adults. What differentiates echinoderm adults,
but not their larvae? Adults should
B) have radial symmetry, or something close to it.
An adult animal that possesses bilateral symmetry is most certainly also
A) triploblastic.
You are trying to identify an organism. It is an animal, but it does not have nerve or muscle
tissue. It is neither diploblastic nor triploblastic. It is probably a
D) sponge.
Some researchers claim that sponge genomes have homeotic genes, but no Hox genes. If
true, this finding would
C) confirm the identity of sponges as ʺbasal animals.ʺ
The distinction between sponges and other animal phyla is based mainly on the absence
versus the presence of
D) true tissues.
Which cells in a sponge are primarily responsible for trapping and removing food particles
from circulating water?
A) choanocytes
A spongeʹs structural materials (spicules, spongin) are manufactured by the
amoebocytes.
Which chemical is synthesized by some sponges and acts as an antibiotic?
E) cribrostatin
In terms of food capture, which sponge cell is most similar to the cnidocyte of a Cnidarian?
B) choanocyte
Which group contains diploblastic organisms?
A) I
Which group consists of deuterostomes?
B) II
The blastopore is a structure that first becomes evident during
B) gastrulation.
Which of the following is descriptive of protostomes?
B) spiral and determinate cleavage, blastopore becomes mouth
Protostomes that have an open circulatory system and an exoskeleton of chitin are part of
which phylum?
D) Arthropoda
Protostomes with a unique drape of tissue that may secrete a shell are part of which
phylum?
C) Mollusca
Which of the following organisms are deuterostomes?
C) echinoderms
D) chordates
E) both C and D
Deuterostomes that have an endoskeleton are part of which phylum?
E) Echinodermata
What is characteristic of all ecdysozoans?
B) some kind of exoskeleton, or hard outer covering
Which of the following was the least likely factor causing the Cambrian explosion?
the movement of animals onto land
Which cells in a sponge are primarily responsible for trapping and removing food particles
from circulating water?
A) choanocytes
In terms of food capture, which sponge cell is most similar to the cnidocyte of a Cnidarian?
B) choanocyte
A radially symmetrical animal that has two embryonic tissue layers probably belongs to
which phylum?
B) Cnidaria
9) Which of the following are characteristics of the phylum Cnidaria?
1. a gastrovascular cavity
2. a polyp stage
3. a medusa stage
4. cnidocytes
5. a pseudocoelom
D) 1, 2, 3, and 4
Which of the following is true of members of the phylum Cnidaria?
D) They may use a gastrovascular cavity as a hydrostatic skeleton.
The members of which class of the phylum Cnidaria occur only as polyps?
C) Anthozoa
Which class of the phylum Cnidaria includes ʺjelliesʺ with rounded (as opposed to boxlike) medusae?
B) Scyphozoa
Which characteristic is shared by both cnidarians and flatworms?
D) a digestive system with a single opening
A stalked, sessile marine organism has several feathery feeding structures surrounding an
opening through which food enters. The organism could potentially be a cnidarian, a
lophophorate, a tube-dwelling worm, a crustacean, or an echinoderm. Finding which of the
following in this organism would allow the greatest certainty of identification?
D) a water vascular system
Which of the following is a diploblastic phylum of aquatic predators?
A) Cnidaria
Generally, members of which flatworm class(es) are nonparasitic?
A) Turbellaria
While vacationing in a country that lacks adequate meat inspection, a student ate
undercooked ground beef. Sometime later the student became easily fatigued, and lost
body weight. At about the same time, whitish, flattened, rectangular objects full of small
white spheres started appearing in his feces. Administration of niclosamide cured the
problem. The student had probably been infected by a
D) tapeworm.
20) Which of the following correctly characterizes the phylum Rotifera?
C) parthenogenic reproduction
While sampling marine plankton in a lab, a student encounters large numbers of fertilized
eggs. The studentrears some of the eggs in the laboratory forfurther study and finds that
the blastopore becomes the mouth. The embryo develops into a trochophore larva and
eventually has a true coelom. These eggs probably belonged to a(n)
C) mollusc.
A radula is present in members of which class(es)?
C) gastropods
An organism is able to extend its feeding structure(s) through a hole in its body wall. If the
organism were a sea star, it would extend its
A) stomach.