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BIOLOGY 406 COMPARATIVE VERTEBRATE ANATOMY, SPRING 2006
EXAMINATION #1 (PART 1) - KEY
Date
MULTIPLE CHOICE.For the following multiple choice questions circle the letter in front of the
response that best answers the question or completes the sentence. (20%, 2% each)
1. Which of the following is a synapomorphy of the group Chordata? (i.e., found
in ALL Chordates but NOT found in Hemichordates
and/or Echinoderms)
a.
b.
c.
d.
e.
brain
cranium
jaws
paired appendages
None of the above. (None are synapomorphies of Chordata.)
2. Which of the following is derived from
ectoderm?
a. digestive tract lining
b. kidneys
c. limb muscles
d. melanocytes (pigment cells)
e. None of the above.
3. Which of the following is derived from
mesoderm?
a. epidermis
b. ganglionic nerves
c. melanocytes (pigment cells)
d. pancreas
e. None of the above
4. Which of the following is derived from
endoderm?
a. epidermis
b. kidneys
c. lungs
d. melanocytes (pigment cells)
e. None of the above
5. Which of the following developmental
tissues will eventually form vertebrae?
a. intermediate mesoderm
b. somite
c. somatic mesoderm
d. splanchnic mesoderm
e. None of the above
6. The book Mutants describes certain birth
defects associated with early development
such as siromelia, cyclopia, and double
faces. Clearly vertebrates can produce
these diverse anatomies. Why don’t we see
these morphologies as the norm in some
living vertebrate groups?
a. Because they only occur in humans.
b. Because they only can be produced
in the laboratory.
c. Because they’re purely
environmental and not genetic.
d. Because they’re usually fatal or
dysfunctional.
7. To which of the following groups of
living organisms are the “fin-backed”
pelecosaurs most closely related?
a. Aves
b. Lepidosauria
c. Lissamphibia
d. Mammalia
e. Testudinea
8. Which of the following vertebrate classes
includes the most species?
a. Actinopterygii
b. Chondrichthys
c. Lissamphibia
d. Mammalia
e. Reptilia
9. To which of the following vertebrate
classes does a bird belong?
a. Actinopterygii
b. Chondrichthys
c. Lissamphibia
d. Mammalia
e. Reptilia
10. Which of the following organisms could
be correctly called a eutherian?
a. alligator
b. kangaroo
c. platypus
d. snake
e. None of the above
FILL-IN-THE-BLANK/LABEL.For the following exercises write the appropriate word or words
in the available space. (10%)
Use the diagram below to fill in the
indicated structures to the right.
1. Label the indicated substances in the
diagram at left. (9%)
A salivary gland* (submand. or sublingual)
B
esophagus
C
stomach (or fundus)
D
pancreas
E large intestine (or descending colon)
F appendix (or cecum or cecum/appendix)
G small intestine (or jejunoileum)
H
I
gallbladder
liver
2. Use an asterisk (*) to indicate which
structure above is an ectodermal
derivative. (1%)
DEFINITIONS.For the following words or phrases define them as accurately and concisely as
possible. For the terms identified by an asterisk (*) also indicate the taxonomic group of
vertebrates in which it is found or occurs. (20%, 4% each)
1. Cleft Palate:
when fusion of the secondary palate does not occur along the midline (of mammals)
resulting in a space in the roof of the mouth connecting the oral and nasal cavities
2. Coelomic (pleuroperitoneal) fold*:
embryonic transverse fold across the coelomic cavity that will separate the pleural and
peritoneal cavities of mammals
3. Homology (modern comprehensive definition):
similarity due to continuity of biological information or instruction
4. Mesothelium:
simple squamous epithelium lining the coelom (derived from lateral plate mesoderm)
5. Proctodeum:
developmental ectodermal invagination (inpouching) that forms the cloaca and rectum
BIOLOGY 406 COMPARATIVE VERTEBRATE ANATOMY, SPRING 2006
EXAMINATION #1 (PART 2) - KEY
Date
Name
SHORT ANSWER.Address each question in as concise and lucid a manner as possible. Do NOT
exceed the space provided.
1. Use the following data matrix to reconstruct the phylogenetic relationships among the
organisms included below. Be certain to show the synapomorphic characteristics on the tree.
Identify any homoplastic characteristics. (14%)
human
rat
dolphin
hippo
cow
opossum outgroup
1
0
0
1
1
1
0
2
1
1
1
1
1
0
3
0
0
1
1
1
0
4
0
0
1
1
0
0
5
1
1
0
0
0
0
6
1
0
1
1
0
0
4-1 (or aquatic);
6-1* (or reduced hair*)
1-0 – 1 stomach chamber, 1-1 – 4 stomach chambers
2-0 – short gestation; 2-1 – long gestation
3-0 – short skull; 3-1 – elongate skull
4-0 – terrestrial; 4-1 – aquatic
5-0 – diffuse placenta; 5-1 – discoidal placenta
6-0 – hairy body; 6-1 – reduced body hair
dolphin
1-1 (or 4 stomach chambers);
3-1 (or elongate skull)
hippo
cow
2-1 (or long gestation)
rat
5-1 (or discoidal placenta)
6-1* (or reduced hair*)
* indicates homoplastic characteristic.
human
[acceptable if outgroup is depicted or not]
2. Based on your reading of the book Mutants, BRIEFLY, from an embryological perspective,
explain how human conjoined twins form. At which developmental stage does the process
that forms conjoined twins begin? (6%)
Conjoined twins can form when two primitive streaks (regions of gastrulation) occur
somewhat closely together in the same human embryo. They occur on the same
blastodisc (flattened region of blastula around disc shaped blastocoel). [Indicating that
two Hensen’s nodes or regions of SHH expression are also acceptable correct answers.]
3. Compare and contrast the early development (up to and including the formation of the central
nervous system) of a frog, a chicken, and a human. Be sure to identify basic similarities and
obvious differences. (Feel free, but do not feel obliged, to use a table and/or labeled sketches for your answer.)
(15%)
frog
chicken
human
holoblastic
meroblastic
holoblastic
gastrulation
“typical”
primitive streak
primitive streak
neurulation
primary anteriorly;
secondary posteriorly
primary anteriorly;
secondary posteriorly
primary anteriorly;
secondary posteriorly
fertilization etc.
external fertilization
(ova released by
female)
internal fertilization; internal fertilization;
packaged embryo laid embryo implants
forming placenta;
by female
mature embryo
(baby) “laid” by
female
cleavage
(this part not
required for full
credit)
4. Identify the extraembryonic membranes of a typical amniote and indicate the physical
relationship of each membrane to the embryo (what does it enclose? Where does it attach?),
which developmental tissues compose each membrane, and the typical function of each
membrane. (Feel free but do not feel obliged to use a labeled sketch for your answer.) (15%)
physical relationship
composition
“function”
chorion
surrounds entire embryo, and
contains everything
-ectoderm
-somatic mesoderm
surrounds and protects entire
embryo
amnion
surrounds the embryo proper
(& amniotic cavity)
-ectoderm
-somatic mesoderm
surrounds and protects
embryo proper
allantois
extends from and contains an
extension of the hindgut
-endoderm
- splanchnic mesoderm
storage or transfer of wastes;
gas exchange; +nutrient
exchange in therians
yolk sac
extends from and contains an
extension of the midgut (incl.
the yolk mass)
-endoderm
-splanchnic mesoderm
transfer of nutrients (no real
function in therians)
yolk sacendoderm; splanchnic mesodermnutrient transfer -
-amnion
-ectoderm; somatic mesoderm
-surround and protect embryo proper
chorionectoderm; somatic mesodermcontains embryo-
-allantois
-endoderm; splanchnic mesoderm
-gas exchange; waste storage/exchange