Making Model Embryos: by: Jewel Reuter, LA Virtual School Donald Cronkite, Hope College Attachment

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Making Model Embryosby Jewel Reuter, LA
Virtual SchoolDonald Cronkite, Hope College
Attachment 5
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The Medaka (A Fish)
Start with an orange and a lump of modeling clay
This will be the part with the nucleus
This will be the yolk of the egg
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A Question
One part of the egg will divide to form many
cells. The other part will not divide, but
provides nourishment for the embryo. Which part
of our model do you think is which?
Which part will be the part of the model that
divides? ?
Which part will be the models yolk?
?
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The Answer
One part of the egg will divide to form many
cells. The other part will not divide, but
provides nourishment for the embryo. Did you come
up with the answer?
Which part will be the models yolk?
?
Which part will be the part of the model that
divides? ?
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The one-cell stage
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To Make More Stages
Study the pictures of development before you
begin so that you can make accurate models of the
stages.
Break your clay into equal sized bits, thus
making two cells, break each of those in half to
form four cells and so on until you reach 32
cells. Lay them down on the orange each time as
shown on the diagrams.
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Making the fishs yolk sac
After many divisions, when the cells have divided
to produce very small cells. The whole layer of
cells moves down to form a yolk sac around the
yolk,. Then the embryo can get nutrients from
the yolk Consult the pictures of fish embryos to
see how your model should look.
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Making the fishs yolk sac
Make a pancake of your clay and put it on the
orange to look like the stage when the cells move
down over the yolk. Then make a ridge along the
center of your developing yolk sac to represent
the early formation of the embryo.
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Making the fishs yolk sac
The ridge that will become the fish. The
growing yolk sac. The yolk.
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A Model of a Human Embryo
Human embryos have only a tiny amount of yolk.
The whole egg cell, which is very small divides
again and again to form a little ball of cells.
Study the pictures of early human embryos and
make each cell division for the first 5
divisions. How many cells are produced in 5
divisions?
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The fertilized eggs journey
The egg is fertilized at the very top of the
oviduct. Then it divides as it moves down the
tube,taking about 7 days for the journey.
1 Week
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The Blastocyst
When the dividing egg reaches the bottom of the
oviduct, it enters the uterus where it will live
for another 35 weeks attached to the mother.
Study the pictures of blastocysts and then figure
out how to make one with clay.
When the embryo reaches the uterus it is a
blastocyst, a hollow ball with a lump of cells
at one end.
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Attached
Make a flat piece of clay to represent the wall
of the uterus and then attach the embryo by the
thin membrane.