Name
BIOLOGY 406 COMPARATIVE VERTEBRATE ANATOMY, SPRING 2004
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 Vertebrata? (i.e., NOT
found in Cephalochordata and/or Urochordata.)
a.
b.
c.
d.
e.
endostyle/thyroid
myotomes
notochord
pharyngeal basket/openings
None of the above. (None are synapomorphies of Vertebrata.)
2. Which of the following is derived from
ectoderm?
a. brain
b. dermis
c. digestive tract lining
d. vertebrae
e. None of the above.
3. Which of the following is derived from
mesoderm?
a. epidermis
b. ganglionic nerves
c. kidney tubules (nephrons)
d. melanocytes (pigment cells)
e. None of the above
4. Which of the following is derived from
endoderm?
a. hair
b. musculature of limbs
c. spinal cord
d. stomach lining
e. None of the above
5. Which of the following best describes
mammalian teeth?
a. acrodont, diphyodont, heterodont
b. acrodont, diphyodont, homodont
c. pleurodont, polyphyodont, homodont
d. thecodont, diphyodont, heterodont
e. thecodont, polyphyodont, heterodont
6. Which of the following explains why
ectopic (extra) nipples in humans form in
predictable places?
a. human ectopic nipples form where
stimulation from suckling occurs
b. mammalian nipples develop along
identifiable milk/mammary lines
c. mammalian nipples form only in
regions surrounded by apocrine
sweat glands
d. neural crest cells induce nipple
formation early in their superficial
migration
7. Which of the following is a characteristic
of all three subclasses of mammals?
a. form a placenta
b. have nipples
c. meroblastic cleavage
d. primitive streak gastrulation.
e. None of the above (None are
characteristics of ALL mammals.)
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 caecillian belong?
a. Actinopterygii
b. Chondrichthys
c. Lissamphibia
d. Mammalia
e. Reptilia
10. Which of the following organisms could
be correctly called a lepidosaur?
a. bird
b. gar
c. snake
d. turtle
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 skin section below to answer the
following
2. Label the indicated substances, layers,
and structures in the skin section at left.
(5.5%)
A
C
A (substance) dentin(e)
B
D
B (substance) enamel
C (structure) placoid scale
D (layer) epidermis
E (layer) stratum basale/basal layer
F (structure) mucus cell/mucus gland
F
H
E
I
1. From what kind of organism was this
section drawn and (briefly) how did you
know this? (2.5%)
G
G (layer) dermis
H (layer) stratum laxum
I (layer) stratum compactum
Chondrichthys/shark – has placoid
scales (not a tetrapod bc/ it lacks
a stratum corneum)
DEFINITIONS.For the following words or phrases define them as accurately and concisely as
possible. (20%, 4% each)
1. Basal Cell Carcinoma:
cancer derived from a cell from the epidermal stratum basale.
2. Homology (modern comprehensive definition):
similarity due to continuity of biological information or instruction
3. Secondary Neurulation:
formation of the neural tube by sinking in of solid ectoderm that cavitates
4. Somitomeres:
poorly differentiated mesodermal blocks (somites) in the posterior head
5. Splanchnic Mesoderm:
lateral plate mesoderm that lines the viscera (deep lateral plate mesoderm)
Name
BIOLOGY 406 COMPARATIVE VERTEBRATE ANATOMY, SPRING 2004
EXAMINATION #1 (PART 2)
Date
SHORT ANSWER.Address each question in as concise and lucid a manner as possible. Do NOT
exceed the space provided.
1. Explain how the mammalian (i.e., human) skin develops. Be certain to identify the three (3)
important tissues that contribute to the developing skin and identify the “germ layer” origin
of these tissues. Include the typical glands and structures of the mammalian skin but do not
include the mammary glands. (Feel free, but do not feel obliged, to use labeled sketches for
your answer.) (15%)
1. The (generalized) ectoderm forms the epidermis, the dermotomal component of the
mesodermal somite forms the dermis, and neural crest cells migrate between these two
layers entering both of them forming pigment cells and contributing to other structures.
2. A simple (i.e., one-layered) epithelial epidermis differentiates into a two layers, a
superficial periderm and a deep stratum basale attached to the basement membrane. The
stratum basale continues to divide forming a stratifiued epidermis with a keratinized
surface layer known as the stratum corneum. The periderm is eventually lost.
3. The dermis begins as a region of highly ordered collagen fibers immediately deep to the
epidermal basement membrane. This ordered layer separates from the basement
membrane sinking deeper as a less ordered layer of dermis forms superficially. This process
(delamination) forms the layers of the dermis, the superficial stratum laxum and the deep
stratum compactum.
4. The hair follicles with associated sebaceous glands and sweat glands form when a small
region of epidermis extends as a column of cells deep into the dermis. These columns of
cells then cavitate to form the ducts for the glands to the surface of the skin. The base of
the hair follicle cups a dermal papilla. This is the area from which the hair grows.
2. BRIEFLY explain how and why an outgroup is used in a phylogenetic analysis? (5%)
The outgroup allows the ancestral characteristic to be inferred for a group. (In fancy
systematics language, this polarizes the character transformation.) This makes it possible
to use the inferred evolutionary change as evidence, NOT general similarity which can be
positively misleading, when reconstructing phylogenies.
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
cleavage
holoblastic
gastrulation
“typical” (involution) primitive streak
(ingression)
primitive streak
(ingression)
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
(this part not
required for full
credit)
meroblastic
holoblastic
4. Compare and contrast the integuments (paying special attention to any specialized structures
such as scales or glands) of a lancelet, a shark, a gar, a frog, and a lizard. Be sure to
identify basic similarities and obvious differences. (Feel free, but do not feel obliged, to use a
table.) (15%)
lancelet
shark
gar
frog
lizard
epidermal
layers
simple
stratified
stratified
stratified
stratified
dermal layers
only stratum
compactum
strata laxum &
compactum
strata laxum &
compactum
strata laxum &
compactum
strata laxum &
compactum
scales
none
placoid
ganoid
none
[epidermal
enamel & dermal
dentin(e)]
(epidermal
enamel & dermal
lamellar bone)
epidermal
(keratin)
glands
unicellular
(mucus)
unicellular
(mucus)
unicellular
(mucus)
multicellular
(mucus &
poison)
multicellular
mucus coat
present
present
present
present
absent