Embryology:
BIO SCI 1480
S. Shostak
Fall 2004
First hour exam
Please feel free to spend the entire period (50 minutes but not a
moment longer!) writing your essay. Good answers are usually about 7
double-spaced pages and take about 50 minutes to write.
The rules: Please! (1)write your name and the date on the cover page;
(2) write on every other line and leave wide margins if you would like
me to comment on your paper; (3) include your copy of the exam with
your blue book.
You are to write one (1: only one and no more than one) essay, but you
have a wide choice of topics! What you write will be graded on the
basis of correct specifics with a sharp decline in grade for errors.
Spelling does not count, but it helps, and you might pay attention to
grammar, especially agreement, since this is a writing course!
The rationale: Embryology seems to make sense when you think about
events at one stage of development anticipating events at another
stage—as if something happens earlier in order for something else to
happen later. Development proceeds, after all, through early stages
which might not seem to make sense except as preliminaries to later
stages. On the other hand, scientists think in terms of causes: one
thing causes another, and something happens later because something
else happened before.
Your job here is to illustrate how development happens progressively.
In other words, you must (1) describe an event that happens early in
development, (2) describe how that event is connect to a later event,
and (3) describe the later event.
The exam
The first thing I want you to do is draw a circle around one event from
an early stage of development (see column A other side) and another
circle around one event from a late stage of development (see column B
other side) and then draw a line connecting the two circles. You must
include your copy of the exam with these circles and line when you turn
in your blue book.
Then, I want you to write separate paragraphs describing (1) the event
enclosed by your first circle, (2) the line connecting the two events,
and (3) the event enclosed by your second circle. I would hope that,
collectively, the three parts of your essay will demonstrate how the
event circled in column A is causally related to the event circled in
column B.
Hint: you might use the phrase, “because of” when describing how the
event in column B is caused by the event in column A.
column A
A1. Oogenesis
and/or spermatogenesis
A2. Fertilization
A3. Cleavage
A4. Blastocyst
formation
A5. Implantation
A6.
Extraembryonic gastrulation
A7. Cavitation
A8. Formation
embryoblast
A9. Body folding
A10. Gastrulation and germ layer
formation
A11. Neural crest formation
column B
B1. Induction
anterior-posterior axis and dorsal-ventral asymmetry
B2. Formation
extraembryonic membranes
B3. Blood-cell
differentiation
B4. Induction
central nervous system
B5. Formation
body cavities
B6. Neurogenesis
CNS and PNS
B7. Somitogenesis
and formation axial skeleton
B8.
Vasculogenesis and heart formation
B9. Foregut,
midgut and hindgut formation
B10. Pharyngeal pouch deveopment
Embryology: BIO SCI 1480
S. Shostak
Fall 2003
First
hour exam
Please
feel free
to spend the entire period or leave when you want to, but good answers
are
usually about 8 double-spaced pages and take about 50 minutes to write.
Write your name and the
date ONLY
on the cover page. Please write on every other line and leave wide
margins if
you would like me to comment on your paper.
You may write one,
two or three
essays (but no more) which will
be evaluated
equally. Answers will be graded
on the
basis of accuracy with a sharp decline in grades for errors. Spelling
does not
count, but it helps, and you might pay attention to grammar, especially
agreement, since this is a
writing course!
Prolegomena
Embryology seems to
make sense
when you think about events at one stage of development anticipating
events at
another stage—as if something happens earlier in order to allow something else to happen later.
Development
proceeds, after all, through stages which might not seem to make sense
except
as preliminaries to further development. On the other hand, as
scientists, we
know that one thing leads to another and something happens later because
of things happening earlier.
Your job here is to
illustrate how
development both seems to anticipate (i.e., happens “in order to”)
and causes (i.e., happens “because of”) events at progressively
later times. In other words, you must show me how complexity increases
through
interactions that leap across time from one stage to another.
Exam
What I want you to do for this exam is
illustrate these
complementary concepts of development (“in order to” and
“because of”) by taking one or more events from an early stage of
development and show how it or they both anticipate and affect
events at a late stage.
Please begin by matching an event in column A with
one in
column B (i.e., connect items in the respective columns with a line).
Then,
write an essay in your blue book describing how the (or each) pair of
events
you have matched illustrates both anticipation (“in order to”) and
causation (“because of”).
List of Events and Stages
A1.
Oogenesis and/or spermatogenesis
A2.
Fertilization
A3.
Cleavage
A4.
Blastocyst formation
A5.
Implantation
A6.
Extraembryonic gastrulation
A7.
Cavitation
A8.
Formation embryoblast
A9.
Body folding
A10.
Gastrulation
and germ layer formation
A11.
Neural
crest formation
B1.
Induction anterior-posterior axis and
dorsal-ventral asymmetry
B2.
Formation extraembryonic membranes
B3.
Blood-cell differentiation
B4.
Induction central nervous system
B5.
Formation body cavities
B6.
Neurogenesis CNS and PNS
B7.
Somitogenesis and formation axial skeleton
B8.
Vasculogenesis and heart formation
B9.
Foregut, midgut and hindgut formation
B10.
Pharyngeal pouch deveopment
B11.
Limb induction and signal pathways