SUBJECT: Labs on development and reproduction
DATE: 6/96
Help, I'm looking for a good lab on Animal development and another on
Systematics that doesn't completely bore students to death. I have to come
up with it by next week - any ideas? My budget is non-existant by the way.
=======================
Alison Morrison-Shetlar
Dept. of Biology
Landrum Box 8042
Georgia Southern University
Statesboro GA 30460
There are two "real" development labs that my students love. Unfortunately,
it's too late to set up one by next week, and the other is expensive. But
for future reference, here goes:
1. CHICK DEVELOPMENT: I order fertilized chick eggs from Carolina Biological,
and incubate for various times so that on the lab day, we have many eggs
3
days "old" [incubated for 3 days], and a few 5, 7, 9... 17 days
old. Students
crack open all but the 3 day into dishes, and draw, describe, measure, and
weigh the embryos. I toss in a few parrafin whole mounts from Carolina
from 24, 48, 72, and 96 hour embryos for them to draw as well.
With the 3 day, we do "chick in a cup". Drape untouched saran
wrap over
a styrofoam cup, use somehting sterile to push part of it down into the
cup,
making an indentation large enough to hold the contents of an egg. Wipe
a 3
day egg down with Betadine; crack it into the cup without breaking the yolk.
Add antibiotics; cover with a sterile petri dish cover. Incubate at 38 degrees
C. You can see development occuring in the cup, and watch progression for
about
10 days before the embryos die. GREAT lab! A FEW students object to killing
all those embryos; but most love it.
2. Sea urchin fertilization: In any developmental lab manual, you can find
protocol for getting sea urchins to shed gametes; fertilize in a dish, and
view
early development. Can even induce "parthenogenesis" with a number
of procedures;
the one that works best for me is the calcium ionophore A23187. Unfertilized
eggs go through cleavage divisions, sometimes to blastula. Also a great
lab,
but you need a salt water tank, and an inverted microscope helps. The urchins
can be expensive; I get them from Gulf Specimen in Florida; including next
day shipping they go for about $60/dozen.
-Bob Moss
Wofford College
MOSSRE@WOFFORD.EDU
In a recent posting, Alison Morrison requested some ideas for good (and
cheap!) labs in the area of animal development. Here are a couple of ideas:
1) planaria regeneration
These animals can be collected (free!) from local streams, then the
students can cut them up and observe how the regenerate. For a reference,
check out Johnson and Volpe's "Patterns & Experiments in Developmental
Biology" 2nd ed, by Leland G. Johnson, published by WmCBrown. Chapter
16
gives directions for observing regeneration in protists and animals,
including planaria. Essentially, you just need a supply of spring water
to
culture them in (works better than Ringer's) and small ice cubes (ice
frozen in small pill boxes will work well) to anesthetize them while the
cuts are made (with sterile scalpel blades). You should see results within
a week, depending on the size of the fragments.
2) temperature and development in fruit flies
Again, this is a cheap lab focusing on development. Have the students
separate out fruit flies at different stages (eggs, first instar, third
instar, early pupae, etc.) Transfer about 10 of each stage to separate
vials (have 3 vials with 10 eggs, 3 vials with 10 pupae, etc.) Place the
vials at different temperatures (18, 25, 29) and observe the effects on
the
speed of metamorphosis. At those temperatures, the flies should all be
viable, but the 18 degree eggs may take over a month to eclose. You could
also look at the effects of short-term exposure to higher temperatures.
Try
heat-shocking pupae at different stages. Place pupae in sealed test tubes
and immerse them in a hot (40 degree) bath for 35 minutes. Observe flies
for survival and any phenotypic changes (phenocopies). For a reference,
read Mitchell and Petersen's article "Developmental Abnormalities in
Drosophila Induced by Heat Shock" in Developmental Genetics 3:91-102,
1982.
Good luck!
---------------------------------------------------------------------------
Lisa A. Lambert |e-mail: lambert@chatham.edu | snail-mail:
Associate Professor | phone: (412) 365-1217 | Chatham College
Dept. of Biology | fax: (412) 365-1505 | Woodland Road
Chatham College | | Pittsburgh, PA 15232
To the BioLab net:
We have for some years done a
lab that uses Sea Urchins in the first half of the lab and chicken embryos
in
the last half of the lab. While the lab is warm and fuzzy and gives the
students a chance to see beating chick embryo hearts and possibly seeing
fertilization and maybe one or two cleavages, not much else happens.
We are working on the following and ask the BioLab net if anyone has some
experience or information.
1. Sea Urchin sperm. How do the sperm behave in different pH solutions?
How
do the sperm behave in different viscosity situations? How do the sperm
behave in a weak electric field? All of this would be done in depression
well
slides. Any suggestions for perturbing the sperm????
2. Sea Urchin eggs. How do the eggs behave in different pH solutions? How
do
the eggs behave in a chelated environment? How would the eggs behave if
administered an electric shock??? Any suggestions?
Of course all of this is a prelude to the actual fertilization event. An
event
where most students get the concentration of sperm to egg wrong and often
don't
know what to look for when it happens. By handling the sperm and egg before
hand, the student will have gained experience before looking at fertilization.
3. If we were to add EDTA and change the ionic conditions, could we get
poly-
spermy? What stains and/or microscopy tricks could we employ to see syngamy
better? Remember we have $1500 student microscopes and first year students.
Now to the chick embryo. If the lab sections were to collect the weight
of the
embryos for each day of incubation, we could get a large data set that would
let the students determine if growth is exponential. They could curve fit
a
model. They might be able to look for a logistic curve as well when growth
moves out of the exponential period. They could graph the weight data to
semi-
log paper and look for a straight line and discuss what this means. They
could
compare embryo weight to that of egg weight and determine if there is a
correlation. And so forth.
We are trying to get away from the straight "look I think that is fertilization
" and "look at the beating heart" to the point where students
really ask
some questions about the living material.
Comments, extensions, what if's, your'e nuts, whatever. Thanks for considering
this long request.
Blystone in Texas
**********************
ROBERT V. BLYSTONE PHONE:(210)736-7243
DEPARTMENT OF BIOLOGY FAX:(210)736-7229
Trinity University E-Mail:RBlyston@Trinity.edu
715 Stadium Drive
San Antonio, TX, 78212
"Blystone in Texas" wrote"
>>We are trying to get away from the straight "look I think that
is
>>fertilization " and "look at the beating heart" to
the point where
>>students really ask some questions about the living material.
This is our goal too, but it's difficult to do in large labs.
When we have given students the opportunity to
devise their own questions, we are always impressed by their
imagination and exuberance in carrying out the experiments.
WRT the chick embryo lab, we follow the procedure presented at an
early ABLE meeting by Rithanne Pitkin. The students actually dissect
out the heart and put it into culture. They measure the beat rate
during the different stages in the procedure. If they successfully
excise a whole heart, they do a second heart on which they dissect the
three parts of the heart from each other and note the change in beat
rates of each section.
Students are somewhat intimidated by the difficulty of the
microdissection, but for those that perservere they usually achieve some
success.
Best regards, Graham Kent
Smith College
One addition we used with great success was, as students finished with the
"regular" parts of the lab, we had available a variety of "human
spermicidal products" such as jellies, foams, creams, etc. which they
could put into the sperm solution for a few seconds, and *then* add the
sperm to unfertilized eggs and watch to see if the rate of fertilization
decreases, and by how much. Some students would also use salt, hot water
in 10 degree increments, Coca Cola (amazing how many students through this
century have believed that this, shaken, is an effective spermicidal
douche; many of them are parents), and so on. This lab had a salutatory
effect on student personal behaviours as well as being an interesting
quantitative addition to a mostly qualitative lab.
On the other hand, explaining to the store clerk *why* you're buying all
these interesting items in bulk, plus explaining to the department
secretary how to write up the invoice, do make for a strange day... ;-)
JodyLee Estrada Duek jduek@u.arizona.edu
Faculty Development Specialist 520/626-2203
Division of Academic Resources 520/626-6707
U. of Arizona School of Medicine 520/626-4879 (fax)
1501 N. Campbell Avenue
Tucson, Arizona 85724-5120
Graham Kent's comments on dissecting out the heart of a frog brings to
mind my own experience with this. My first experience was one of
amazement that a heart would still beat after it had been removed from the
rest of the animal. I no longer do this exercise because of the animal
rights problems, but for those of who who are still doing it, I offer a
suggestion. Use this experience as a basis for discussing some medical
issues. When my Mother had a heart attack, she was revived 15 minutes
after her heart had stopped. She was kept alive on a machine until after
I arrived, but she was brain-dead. When we talked to the minister, he had
trouble dealing with the concept that we considered her to be dead until
I
explained the frog story to him. I told him that the frog's brain had
been killed and that the heart continued to
beat, even though it ws removed from the body and asked him if he
considered the frog to be alive. Then he understood why I could consider
my mother to be dead even though her heart beat. It may help the students
when they have to deal with similar questions some day.
I am inclined to favor one demonstration of this, with a diseased
frog that will die in a few days anyway. I find it hard to justify to
myself or my students otherwise. I think the beating heart is
sufficiently unusual to the students that they will remember it without
doing it themselves, but each should get a good close look.
Janice
***********************************
Janice M. Glime, Professor
Department of Biological Sciences
Michigan Technological University
Houghton, MI 49931-1295
jmglime@mtu.edu
906-487-2546
FAX 906-487-3167