1.
The
recent reassessment of animal classification is the result of comparisons of
DNA and rRNA among different taxa.
2.
An
acoelomate is an animal that has neither a coelom nor a pseudocoelom.
3.
Germ
layers are embryonic layers with different developmental potentials.
4.
During
the Cambrian Explosion, the evolution of Hox genes is thought to have
assisted rapid speciation because simple changes in the expression of Hox
genes lead to large variation among certain important morphological
traits.
5.
If you could travel in a time machine back to
the Cambrian Explosion, which animals would you expect to see most commonly?
sponges, arthropods, flatworms
6.
Animal classification based on morphology.
§
Animals
collectively known as the Eumetazoa possess specialized tissues.
§
The
Eumetazoa are divided into the Radiata and the Bilateria; this division is
based upon each group’s unique symmetry.
§
The
Bilateria are, in turn, divided into three major classifications based upon the
structure of the body cavity.
§
This
feature is important because it allows for organs to be cushioned by fluid
that is relatively incompressible.
§
Lastly,
animals can be classified by the way their zygotes subsequently divide to form
a multicellular individual; the embryological pathway can proceed by either radial
or spiral cleavage.
7.
Bilateria are characterized by a plane of
symmetry that forms mirror images around a vertical plane in the midline.
8.
Triploblastic are animals that have three
germ layers.
9.
Check the phyla that are considered to be
lophotrochozoans: Platyhelminthes, Mollusca, Annelida, Rotifera
10. Coelomates
are animals that have a true coelom
11. You
are presented with a newly discovered invertebrate species. As you
observe it in your lab, you note that the animals shed their skin. Which
designation might this lead you to consider? Ecdysozoa
12. The
development of segmentation in animals has led to several adaptive
advantages.
§ Locomotion
is more efficient in segmented animals because individual segments can move
semi-independently. True
§
Partitions isolate each segment so each must
contract or expand in unison. false
§ In
segmented animals like earthworms (phylum Annelida), each segment may develop a
nearly complete set of adult organ systems. True
§ Redundancy
in segmented animals is not an advantage. False
13. Select
the reasons why choanoflagellates are thought to be the closest living
relatives to animals.
§
Molecular comparisons between choanoflagellates
and simple animals are similar
§
They are similar to the cells of simple animals
14. All
animal species have general characteristics in common. Check all of the
characteristics that would apply to members of this kingdom
§
Most animals have a muscle system that allows
for active movement
§
Most animals undergo sexual reproduction where a
small motile sperm cell unites with a larger egg cell to produce a zygote
§
All animals are heterotrophs
15. Attribute
one of these statements to the blastopore: It occurs in both
protostomes and deuterostomes
16. An
organism in your lab has issues with a malformed central nervous system that
can be traced all the way back to the embryonic stage. To further
investigate this issue, which germ layer would you want to examine closely to
get an idea of exactly how the malformation occurred? Ectoderm
17. When
division of the zygote reaches the eight-cell stage and the planes of cleavage
of the upper four cells line up with those of the bottom four cells so that two
tiers of cells result, one directly above the other, the type of cleavage is
called radial cleavage
18. Cephalization
is concentration of the sensory organs on the anterior end of the body
19. Stem
cells have determinate cleavage; False
20. The
animal kingdom is a monophyletic grouping;True
21. A
hydrostatic skeleton has no bones or cartilage;True
22. Which
characteristics are included in the Lophotrochozoan grouping? a crown of
tentacles,
|
trochophore
larvae
|
23. Which
of the following correctly describes the fate of the embryonic germ layers?
|
The
endoderm forms the gut, the ectoderm forms the epidermis and parts of the
nervous system, and the mesoderm forms muscles and most internal organs
|
24. You
are given a new animal species to study. You note that it possesses
segmentation. Knowing only that it is segmented, which would be possible
phyla for this species? Arthropoda, Chordata, Annelida
25. If
you conducted an experiment in which you took a complete animal that had no
germ layers and strained it through a fine-mesh cloth so that all its cells
separated, then you placed all the cells together and they reunited to form a
new animal, to which phylum would that animal likely belong? Porifera
26. What
is a characteristic of most animals? They have Hox genes
27. You
are given an embryo with eight cells and you carefully separate them and allow
them to develop in separate containers. Each of the cells forms a complete
embryo that develops normally into an adult animal. How would you categorize
your animal?
|
It
has indeterminate cleavage
|
28. Compare a
pseudocoelom to a coelom.
|
A
coelom is completely enclosed by mesoderm whereas a pseudocoelom has an outer
covering of mesoderm and an inner one of endoderm
|
29. Forelimbs
form at the junction of the neck and thoracic vertebrae, the position of which
is controlled by HoxC-6 genes. Several kinds of vertebrates from
different classes are limbless, including limbless lizards, and amphibians
known as caecilians. All descended from limbed forms. On the basis of recent
research in genetics, what would you conclude about the functioning of their HoxC-6
genes? The site of expression of their HoxC-6 genes may have moved
anteriorly until the level of expression has eliminated the neck region
30. Choanoflagellates
are similar to the choanocytes that corals possess;False
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