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 the process in which the zygote undergoes mitotic cell division.

• Cleavage

Observe what is happening to the size of the cells as cleavage occurs.

Cleavage in Clam embryonic developmentObserve what is happening to the size of the cells as cleavage occurs.

Are the cells growing?- NO CELL GROWTH

1

2 3

54

Identify the numbers that represent cleavage.

3. Identify the structure that forms as a result of cleavage.

• Morula

Occurs 3 days after fertilization.

4. Describe a morula.

• Solid ball of cells

Consists of 16 cells

5. Identify the structure that forms AFTER the morula and describe its structure.

• Blastula• Hollow ball of cells

Identify the blastula. Support your answer.

In humans, blastulation takes approximately 4-5 days.

1

2 3

54

1. Identify the morula.2. Identify the blastula.

Morula Blastula

http://www.youtube.com/watch?v=6lnr4HWiz9M

This takes about 6–7 days

1. Identify the zygote.2. Where is cleavage occurring?3. Identify the photo showing the blastula.

Zygote Cleavge Cleavage

Blastula

6. Identify the structure that the blastula attaches to.

• Endometrium (lining of uterus)

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 periodso Pelvic paino Pain with urination or bowel

movements (often during monthly periods)

o Trouble getting pregnant

7. Identify the structure that the forms after the blastula.

• Gastrula

Describe the difference between structure of the blastula and gastrula.

8. Identify the three layers that make up the gastrula.

• Endoderm• Mesoderm• Ectoderm

A

B

C

Look at the prefix of each word to help you identify each layer.

•Endoderm•Mesoderm•Ectoderm

1. Endoderm = inner layer2. Mesoderm = middle layer3. Ectoderm = outer layer

A

B

C

Mesoderm

Ectoderm

Endoderm

http://www.youtube.com/watch?v=Lgb4wMsZwZA&feature=related

Gastrulation

Do any of the cells that make up these structures have a function?

What are these cells called?

9. Identify and describe the process that occurs to the three germ layers that make up the gastrula.

• Differentiation• Layers start to develop into

different cells and eventually different structures

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