Topic: Reproduction
Aim: Describe the stages of embryonic development.
Do Now:
1. Describe the process of fertilization.
2. Describe the types of organisms that use external
fertilization.
3. Describe the types of organisms that use internal
fertilization.
HW: Work on your science fair board.
CL Mitosis and Asexual Repro due Tuesday,
February 24th
1. How
does a
zygote
move
through
the
oviduct?
• Smooth muscle contractions
• Cilia lining the oviduct
2. Identify • Cleavage
the
process in
which the
zygote
undergoes
mitotic cell
division.
Observe what is happening to the size of the cells
as cleavage occurs.
Cleavage in Clam embryonic development
Observe what is happening to the size of the cells
as cleavage occurs.
Are the cells growing?
- NO CELL GROWTH
1
2
4
3
5
Identify the numbers that
represent cleavage.
3. Identify • Morula
the
structure
that forms
as a result
of
cleavage.
Occurs 3 days after fertilization.
4.
Describe a
morula.
• Solid ball of cells
Consists of 16 cells
5. Identify • Blastula
the
• Hollow ball of cells
structure
that forms
AFTER the
morula and
describe
its
structure.
Identify the blastula. Support
your answer.
In humans, blastulation takes approximately
4-5 days.
1
2
4
Morula
1. Identify the morula.
2. Identify the blastula.
3
5
Blastula
Zygote
Cleavge
Cleavage
Blastula
http://www.youtube.com/watch?v=6lnr4HWiz9M
1. Identify the zygote.
2. Where is cleavage occurring?
3. Identify the photo showing the blastula.
This
takes
about
6–7
days
• Endometrium
6. Identify
(lining of uterus)
the
structure
that the
blastula
attaches
to.
Occurs 9 – 10 days after
conception.
• Endometriosis occurs when
tissue normally found in a
woman’s uterus grows outside
of the uterus.
• Each month, this displaced
tissue goes through the normal
menstrual process, thickening
and then shedding through
bleeding. However, since it has
no way to exit the body, it
becomes trapped and can
irritate the areas around it,
causing pain, scarring, infertility
and other issues.
• The cause of endometriosis is
not known. Symptoms include:
o Painful periods
o Pelvic pain
o Pain with urination or bowel
movements (often during
monthly periods)
o Trouble getting pregnant
7. Identify • Gastrula
the
structure
that the
forms
after the
blastula.
Describe the difference between
structure of the blastula and
gastrula.
8. Identify • Endoderm
the three • Mesoderm
layers that • Ectoderm
make up
the
gastrula.
A
B
C
Look at the
prefix of each
word to help
you identify
each layer.
• Endoderm
• Mesoderm
• Ectoderm
1. Endoderm = inner layer
2. Mesoderm = middle layer
3. Ectoderm = outer layer
A
Mesoderm
B Ectoderm
C Endoderm
Gastrulation
http://www.youtube.com/watch?v=Lgb4wMsZwZ
A&feature=related
Do any of
the cells
that make
up these
structures
have a
function?
What are
these cells
called?
9. Identify • Differentiation
• Layers start to develop into
and
different cells and
describe
eventually different
the
structures
process
that occurs
to the
three germ
layers that
make up
the
gastrula.
1. Identify
what the
cells of the
ectoderm
differentiate
into.
2. Identify
what the
cells of the
mesoderm
differentiate
into.
3. Identify
what the
cells of the
endoderm
differentiate
into.
10. Identify the process represented by
process 1.
Fertilization
11. Identify the name of structure 2 how
many chromosomes it contains (in
humans).
46
12. Identify the process occurring in
structure 3 and 4.
Cleavage
13. Identify structure 5.
Morula
14. Identify structure 6.
Blastula
15. Identify structure 7 and the three
layers that make up this structure.
• Gastrula
• Endoderm, mesoderm and ectoderm
16. Identify the process that occurs after
structure 7 is formed.
Differentiation