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Activity
1: Getting to Know The Basics of Embryonic Development – From One,
Many
Read the following to help you get prepared for the lesson by
introducing you to important vocabulary and overall concepts.
You and I and all the other humans started out as gametes –
an egg and a sperm. Those gametes fused to form a zygote – each
of us were once this single cell. Then the zygote divided into two cells
by a process called mitosis. The cells divided, and the resulting
four cells divided until eventually we were many cells. Those cells
continued to divide by mitosis, but some of the cells began to change, differentiate,
to become all the cells of the human body, more than a trillion cells in
more than 200 different forms.
Fish, too, start out as gametes that fuse to form a zygote that
divides to produce many cells by mitosis. These cells change,
differentiate, to become a large number of different types of cells.
There are differences in detail from the process in humans, but they are
enough alike that many biologists study fish embryos to learn about
humans. The fish are a "model system." Human embryos are
unobtainable and subject to ethical concerns. Some fish embryos are
large (for embryos), easy to obtain, and less subject to ethical
questions.
The lesson is centered around you helping a student understand how
embryonic development could help his grandfather who is sick with
Parkinson's Disease. This lesson begins with the study of mitosis and
then explores the model system of Medaka fish embryos. You will
look at movies, make clay models and use a microscope to watch the
development of real embryos. You will get to write a Web Page that helps
to tie together the ethical concerns of cloning and the use of stem cell
in treating disease.
Activity 2: Can Embryological Studies Cure Diseases? An Introductory
Story
Read Can Embryology Studies Help Cure Diseases (Attachment #2 or
http://www.classtech2000.com/biolvhs/embryo/App1c.htm)
This is a story about a student's grandfather who has Parkinson’s
disease. This story will help you get interested in the study of
embryology and will end with the question, "How can the illness of
an old man relate to the early development of embryos?" This
activity will help you understand the importance of learning embryology.
Activity 3: From One to Many Cells-
Viewing Mitosis Web Movies and Singing the Mitosis Song
Part A: Read the following:
Cells divide to form more cells. At such times a special process called
mitosis assures that the two new cells have exactly the same chromosomes
as the original cell. You will watched animations
of mitosis in the next
exercise using the Web pages. Mitosis is very important because it is
the process that assures that each cell will receive a complete set of
chromosomes from the cell that divided to form them. Mitosis is a little
complicated, so people have come up with all sorts of methods for
remembering what happens. Here, for instance, is a song to help you
remember mitosis. Sing or read the song while watching one of the
animated illustrations. (Attachment #3 or
http://www.classtech2000.com/biolvhs/embryo/App2c.htm)
Part B: Study about cell division by studying the following Web
sites, which are images and animations of mitosis.
Learn to recognize the stages of mitosis from the animated Web Site,
The Cell Cycle and Mitosis Tutorial: Mitosis. Go to: http://www.biology.arizona.edu/cell_bio/tutorials/cell_cycle/cells3.html
1) Look at the images and read the captions.
2) Look at the movie, Mitosis Animation. The link to this
movie is at the bottom left side of the page.
Part C: Sing The Mitosis Song
(Attachment # 3 or
http://www.classtech2000.com/biolvhs/embryo/App2c.htm)
It will help you remember the names of the steps of mitosis and the
features of each step. Now review the movies of mitosis while reading
the Mitosis Song.
Part D. Mitosis Movies and Images
Look at more mitosis movies.
Animal Cell Mitosis at
http://www.cellsalive.com/mitosis.htm
Mitosis at
http://tidepool.st.usm.edu/crswr/mitosismov.html
Three Web sites are
provided so that you can see different animations and also to ensure
that you will see an animation. If you are having difficulty loading a
movie from a Web site, do not worry as long as you see at least one.
Part E. Complete the Mitosis Placemat
This placemat will help you review mitosis in a fun way. (Attachment
#4 or http://www.classtech2000.com/biolvhs/embryo/mitomat.htm
)
Activity 4: A Model System to Help Us See How Cells Become Different
Part A: Read the following:
Fish are a "model system" for understanding humans. A model
system is an organism with characteristics that make it easier to study
than humans. You will be using Medaka, the Japanese rice fish,
which is a very good model system.
1. The shell of its egg is transparent, so you can see it easily.
2. A single female will produce 5-10 eggs per day.
3. It is easy to set the time when eggs are produced by putting the fish
in an aquarium that is on a
cycle of light and dark each day. They lay eggs just after the light
comes on.
4. The eggs remain stuck to the female fish, so you can remove them with
a little brush.
5. Development is not too fast, so you can see each stage.
We will study the Medaka and then compare it to what happens
in humans.
Part B: Looking at Movies to See How Cells Become Different in Medaka
Embryos
Look at movies of development of fish and humans found on the sites
referenced below. Observe how the cells divide, change in appearance,
and move to form the embryo. These movies will help you make the clay
models in the next activity. Visit the following Web sites and make the
observations that are requested.
1) Go to Medakafish Developmental Stage Map
http://biol1.bio.nagoya-u.ac.jp:8000/stage-map.html
2) Look at the animation of Medaka development at the top of
the page. (It may take a few seconds for it to begin to play.
(Please be patient.) Observe how the cells divide, change in appearance,
and move during embryological development. Be sure to observe all of the
animations from stages 0 - 44.
3) Look at the following stages of development that are on the list
below. If you have time you can look at more stages. You will use
these diagrams to create your clay models in the next activity, Making
Clay Models of Fish Embryo Development.
Unfertilized
eggs, Activated
egg, Blastodisc
, 2
cell, 4
cell, 8
cell, 16
cell, 32
cell, Early
morula, Late
morula, Early
blastula, Late
blastula, Early
gastrula, Mid
gastrula, Late
gastrula, Early
neurula, Late
neurula, 4
somite, 18-19
somite, 35
somite, Heart
development, Hatching,
1st
fry, 3rd
fry, 2nd
young fish
4) Now go to
Development of the Japanese Medaka (Oryzias latipes) Quicktime
Movies at:
http://biog-101-104.bio.cornell.edu/BioG101_104/tutorials/Medaka_videos.html
You will see the living Medaka
embryo's heart beating in these movies. At 46 hours after fertilization,
you will see a strong heartbeat. As it matures you will see a better
heartbeat, and its dark pigmented eyes.
Look at the following movies on the list on that page, and if you have
time you can look at more of them at the end of the lesson.
5) Go to Heartbeat Stage 23 (46 hours post fertilization).
Watch this movie and be patient to see the heart beat.
http://biog-101-104.bio.cornell.edu/BioG101_104/tutorials/Medaka/Heart_stg23.html
6) Go to Heartbeat Stage 28 (72+hours post fertilization).
Notice that the embryo is more developed and has a stronger heartbeat.
http://biog-101-104.bio.cornell.edu/BioG101_104/tutorials/Medaka/Heart_stg28.html
7)
Now Watch Hatching Fish. Notice the gill movement and its
whipping tail as it swims.
http://biog-101-104.bio.cornell.edu/BioG101_104/tutorials/Medaka/Fry_move.html
Part C: Looking at Movies to See How Cells Become Different in Human
Embryos
1) Go to Human Development (1-cell to week 6). Watch the
animation and see how the cells move and how the human is similar and
different from fish embryos.
http://www.luc.edu/depts/biology/dev/humandev.htm
2)
Go to Humans 4- 7 Weeks. Watch the animation of a real
human embryo. Be patient so you see the entire video.
http://www.esb.utexas.edu/kalthoff/bio349/morph.mov
Activity 5: Making Clay Models to See How Cells Become Different
Part A: Read the following:
Background for Making Clay Models
Medaka eggs divide to form
a flat plate of cells on top of a ball of yolk. The cells keep dividing
and then begin to migrate to form the earliest version of the fish body.
Finally, the cells of the different parts of the fish body begin to
change and specialize to form the organs of the fish. This process can
be divided into three parts:
1) early cell divisions in which the cells get smaller at each division
and form a fluid-filled ball of cells called the blastula;
2) cell migration during gastrulation to form three overall layers of
the embryo (called ectoderm, endoderm, and mesoderm -- the "three
germ layers"), and
3) organ formation, with each organ and organ system coming from
particular germ layers. We can make clay models to study fish
development, which is very similar to human development. You will learn
about the first two parts of the process -- cell division and cell
migration -- by making clay models of key steps.
Part B: Read the following:
1) PowerPoint on Making Embryo Models. (Attachment #5 or
http://www.classtech2000.com/biolvhs/embryo/clay/frame.htm)
Look at this Making
Embryo Models PowerPoint Web page or
downloadable
MS PowerPoint File You
will make the embryo model in Part C below. This PowerPoint has
directions on how to make the clay embryo models.
2) For the details about how the cells are positioned in the model
use Medakafish
Developmental Stage Map
(http://biol1.bio.nagoya-u.ac.jp:8000/stage-map.html)
Web site. You should take
notes on and/or sketch the stages from zygote to the 32 cell stage while
looking at the Web site images. (You may want to review other detailed
images and movies of the previous lesson if you have time.) Be sure that
the PowerPoint Making Embryo Models and the Web site are viewed. More
details of making the Embryo Models are in Part C below.
Part C: Read the following:
The Actual Making of Clay Fish Embryo Models
Use The Fish Embryo Clay Model Table Worksheet (Attachment #6 or http://www.classtech2000.com/biolvhs/embryo/clay/clayws.htm)
to help you make the model. As you make the models you need to make
labeled diagrams on the worksheet. The worksheet and the information
below will help you make the models correctly. Embryo Clay Models and
Diagrams (Attachment 7 or http://www.classtech2000.com/biolvhs/embryo/clay/claydia.htm)
is a table of simple diagrams and pictures of the actual clay models and
may be provided to you by your teacher.
Each student or group of three students uses a ball of clay about the size
of a golf ball and an orange or grapefruit. Be sure you have studied
the pictures of the fish egg at the very beginning of development. At
this point the egg has been fertilized and is a single cell. Use the
fruit for the large ball of yolk and shape the clay to resemble the part
of the cell that will give rise to the embryo. Then follow the
development of the egg as it divides into two cells, four, eight and 16
cells. Notice the pattern of divisions. Notice also that only the clay
part divides. The clay part is the part that contains the nucleus.
Mitosis happens inside each cell when it divides. Finally, make a model
of the egg at early gastrulation when the layer of many cells begins to
surround the yolk. Be sure you follow the directions in Making Embryo
Models (Attachment #5 or
http://www.classtech2000.com/biolvhs/embryo/clay/frame.htm).
Save this last model until
tomorrow. (Be sure to show your teacher.) Notice the early pattern of
cell division and layer formation.
Part D: Read the following:
How can cells that are all the same become different?
You have just learned that
all the cells of the embryo arise from mitosis and that mitosis results
in all of the cells having the same chromosomes. Since the chromosomes
contain the genes, this means that all the cells have the same genes.
Yet they become different from each other fairly early, giving rise to
many hundreds of different cell types. How can cells become different if
they all have the same genes? This is one of the most important
questions of modern biology. What do you think the answer is? (Start
thinking about the answer. You will get to include the answer to this
question in your Web page.)
Activity 6: Making Models of Human Embryos (From Fish to People ---
Similar Process, Similar Questions)
Part A: Read the following background material.
Now you can apply the model system to understanding humans. Human
zygotes divide to form first a solid ball of cells and then a hollow
ball called a blastocyst. Because mammal embryos attach to the
wall of the mother's uterus for most of embryonic development, some
parts of the embryo contribute to this attachment while others
contribute to the embryo. At the stage when the embryo is ready to
attach to the uterus, it is called a "blastocyst"." The
outer layer is called the trophoblast -- it attaches the embryo
to the uterus -- and the inner layer that forms the embryo is called the
inner cell mass. As in fish, human embryos arise from cell divisions,
beginning with the division of the zygote. So once again, a group of
similar cells become all the different cells of the embryo and then the
adults. So there's that question again: How can cells with the same
genes become different?
Part B: Go to Human Development (1-cell to week 6)
http://www.luc.edu/depts/biology/dev/humandev.htm
Study the sketches of the
human embryo at early division and formation of the blastocyst.
Part C: Review Making Embryo Models PowerPoint Web Page
(Attachment #5 or
http://www.classtech2000.com/biolvhs/embryo/clay/frame.htm
) labels to the diagrams.
Part D: Making the model.
1) Make a clay model of a human embryo blastocyst. To make the
blastocyst make the clay into a cap shape and fold it together to make a
hollow ball. Then pinch together some of the clay at one end to make the
lump of cells at one end.
2) Make a flat plate of cells to represent the wall of the uterus, and
attach the embryo to it by its trophoblast.
3) Make labels for the uterus and the blastocyst out of small pieces
of paper. Attach these labels to the model.
4) Keep the model with labels and show your teacher the model.
Activity 7: Viewing Live Medaka Embryos
1) Use Observing and Caring for Medaka Embryo in the Classroom
(Attachment #8 or
http://www.classtech2000.com/biolvhs/embryo/carec.htm
)
for diagrams and more details
on how to observe and care for the embryos to do this activity.
2) Each team receives a few embryos in solution in a small Pitre dish
so that they can look at the embryos under a microscope.
3) The embryos are in rearing solution. Transfer an embryo to a concave
slide with a transfer pipette or look at the embryos while in the Petri
dish under the microscope. Be sure there is some solution with the
embryo, but not so much as to overflow the plate or well in the slide.
4) The eggs are relatively large, so the lower power of the microscope
– a 4X or 5X objective lens – should be all that is needed to view
the embryos. However, you may want to look under higher power.
5) It is important to gently move the embryo with the pipette or some
blunt object so you can have the embryo in a position that allows you to
see the cells and that the yolk is not in the way of viewing the cells.
6) You may also have to adjust the amount of light with the diaphragm or
light aperture control. Look for the heart and pigmented eyes as the
embryo matures. Remember that you might have to gently move the embryo
with the edge of a pipet to get it into a good viewing position.
7) Determine the stage of the eggs by comparing what you see by looking
at the embryo to the diagrams. Make a simple diagram of the embryo. Record
your observations on the Live Medaka Embryo Observation Table
(Attachment #9 or
http://www.classtech2000.com/biolvhs/embryo/medakatc.htm)
. Take a picture of the
embryos if possible.
8) Repeat every 2 days until the embryo hatch. When the fish
hatch transfer them to a tank of dechlorinate water begin to feed them
small amounts of fry food. When they become about 1/4 inch long begin to
aerate them with an air pump and air stone.
Activity 8: Play the Differentiation Game
Play the Differentiation Game
Attachment #10 or http://www.classtech2000.com/biolvhs/embryo/diffgamec2.htm
This game will help to see if you understand cell differentiation.
Activity 9: Stem Cells and Cloning -- Practical Applications of Our
Knowledge of Embryos
Part A: Read From One Cell to
Many Different Cells: A Transition Story (Attachment
# 11 or http://www.classtech2000.com/biolvhs/embryo/diffgamec2.htm).
Read this story to help
you learn more about Parkinson's Disease and the need to learn more
about cloning.
Part B: Background Information about Cloning
Read the following to help you get ready for the cloning activity.
Cloning: Just a few short years ago, a group of scientists in
Scotland succeeded in cloning a sheep. What is cloning? Biologists use
that term to mean all the asexual descendents of a single cell or
organism. A broth culture of a bacterium in which the culture was begun
with a single cell is a clone. A clump of aspen trees, all of which came
up from the roots of one aspen tree, is a clone. Actually, since our
bodies developed from a single cell by mitotic divisions, our bodies are
each a clone too. The sheep that was cloned began with a single cell.
The scientists obtained a sheep egg and removed or destroyed its
nucleus. Then they replaced its nucleus with the nucleus of another
cell. Then this combination of an egg cell and another nucleus was put
into a mother sheep where it developed into a baby sheep. When it was
the right age, it was born just as any other sheep. Even though its
nucleus was from a differentiated cell of an adult sheep, it gave rise
to all the parts of a normal sheep. This is convincing evidence that the
sheep cell that was used had all the genes of a sheep. Otherwise it
could not have given rise to a whole sheep.
Stem Cells: When a blastocyst arrives at the uterus, the
inner cell mass has a fairly small number of cells. In order to make a
complete embryo, each of those cells of the inner cell mass will have to
become several different kinds of cells. When cells give rise to several
different kinds of cells, we call them "stem cells." Stem
cells have become very interesting lately because of their special
property of becoming several cell types. Some people see possible health
benefits from stem cells. Perhaps we will be able to culture cells of a
particular type to replace that kind of cell in people with certain
diseases. Other people are concerned that embryos would be grown for the
purpose of harvesting their organs. They want to stop further research
before that happens.
Part C: How is cloning done?
Watch the movie about The Cloning of Dolly at http://www.luc.edu/depts/biology/dev/shclone.htm.
Notice how one nucleus is removed and another is inserted in the egg
cell. Be sure to look at the 6 steps of cloning on this Web page.
Part D: Making a Model of Cloning
This activity may be done as a demonstration or as a student activity.
Follow the directions given by your teacher.
We will use the following materials and what you learned from the Dolly
Movie to model cloning:
Materials:
2 Small bowls of pre-made Jell-O of light color or 2 small bowls of
thick hair setting gel
1 green grape or green marble
1 red grape or red marble
1 Forceps (tweezers)
Procedure:
1) Place a green grape or green marble in one cup of Jell-O or hair
setting gel using your forceps and this will serve as a model cell.
2) Then place a red grape or red marble in the other cup of Jell-O or
hair setting gel using your forceps, and this cell will represent a cell
from a different animal, an adult donor.
3) Now, using your forceps remove the green grape or marble from the
cell model and dispose of it.
4) Then remove the red grape or marble, nucleus, from the adult donor
cell, and insert into the cell that is missing its nucleus.
Now you have the first cell of the adult donor that you want to clone,
and it will grow and differentiate to form a "clone."
Activity 10: Communicate and Share Your Findings by Making A Web Page
Part A: Study the Embryological Development and Stem Cells PowerPoint
(Attachment #12 or
http://www.classtech2000.com/biolvhs/embryo/stems/frame.htm)
.
Study it so that you can better understand stem cells and their use
in treating illnesses.
Part B: Read Casey Smiles Again: The Concluding Web Story (Attachment
#13 or http://www.classtech2000.com/biolvhs/embryo/App5c.htm)
Read this story so that you
can better understand what it is like to live with a person who is ill
and needs treatment.
Part C: Read the following Web pages:
1) Donor Embryos Fuel Stem Cell Controversy
http://fyi.cnn.com/2001/fyi/news/07/12/stem.cell/index.html
2) Dr. Sanjay Gupta: Understanding stem cell research
http://fyi.cnn.com/2001/HEALTH/07/11/gupta.debrief.otsc/index.html
3) Man’s Own Brain Cells Help Treat Parkinson’s-Study
http://abcnews.go.com/wire/Living/reuters20020408_380.html
Part D: Write a Web Page Using Project Poster. The How to Make
a Poster on Project Poster (Attachment #14 or
http://www.classtech2000.com/biolvhs/embryo/pposterc.htm),
which is directions for
using Project Poster, will give you the Internet address for Project
Poster. Please study the direction on how to use Project Poster.
What Your Web Page Must Contain:
Pretend you are a journalist writing a Web page on new treatment for
Parkinson's disease and you are using Casey's grandfather and family as
human interest to the story. Write a Web page that addresses the
following:
1) Refer back to the stories about Casey's grandfather, select something
that makes it urgent that a cure for Parkinson's disease be found
immediately and include this information at the beginning of the article
as an attention grabber.
2) Answer the question, "How can the illness of an old man
relate to the early development of embryos?"
3) Briefly explain the cause or symptoms of Parkinson's Disease.
4) Briefly explain how stem cells could be used to treat Parkinson's
Disease.
5) Do you agree or disagree with the use of stem cells and why.
6) Include an image that makes sense with your article. If it is from
a Web site or any publication, be sure to cite the reference with the
Internet address or publishing information. If possible use an image
that you or a classmate took while doing the laboratory.
7) Include at least one Internet link that supports or extends your
article.
8) Have a title that reflects the content of your article.
9) Use proper grammar and organization.
10) The article should not exceed 250 - 300 words.
11) Print your Web page and show the edits that you made as a result of
the peer review process of Activities E and F below.
Part E: Peer review your classmates' poster Web pages by seeing if
they included the required components and score them on each from 0-9 (0
being the worst and 9 being the best) and complete the Web page
Evaluation form (Attachment # 15 or
http://www.classtech2000.com/biolvhs/embryo/pposterc.htm)
Include an
explanation about why you gave points for each component as feedback.
Part F: Edit poster Web pages to reflect suggestion from peer review
process.
Use the suggestions in Part E. above to edit the Web pages.
Attachment #1
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