1. Meiosis and Sexual Reproduction
Chapter 7

2. Chapter 7 Vocab 7. Ovum- mature egg cell. 8. Homologous 9. haploid
1. Meiosis
2. Crossing-over
3 independent assortment
4. Spermatogenesis- special cell division in males that results in 4 haploid gametes.
5. Sperm
6. oogenesis- a special type of cell division in females that results in creation of a single ovum.
7. Ovum- mature egg cell.
8. Homologous
9. haploid
10. Fertilization
11. diploid

3. Meiosis
A. meiosis- a form of cell division that reduces the chromosome number by half, forming specialized cells (egg & sperm)

4. b. The nucleus divides twice!
1. Meiosis I and Meiosis II- each goes through the following stages:
A. prophase
B. metaphase
C. anaphase
D. telophase- includes cytokinesis
The result is 4 haploid cells

5. Review Questions 1. How is meiosis different from mitosis?
2. How many times does the cell divide in meiosis?
3. How many cells are made from meiosis?
4. Are the new cells haploid or diploid?
5. Where in your body does meiosis occur?

6. Meiosis Contributes to Genetic Variation
1. Chromosomes pairs separate independently
A. independent assortment- random distribution of chromosomes during meiosis
B. 23 pairs of chromosomes give 223 (about 8 million) different gamete combinations are possible

7. Crossing-over and random fertilization
A. Crossing-over: the exchange of DNA segments between homologous chromosomes.
B. this makes genetic combinations unlimited
C. fertilization of gametes is random- 64 trillion possibilities.

8. The Importance of Genetic Variation
A. genetic variation is essential to evolution.
B. the greater the variation the faster evolution occurs.
C. evolutionary change must be favored by natural selection.

9. Review Questions 6. How are chromosome pairs separated during meiosis?
7. What is crossing-over?
8. Why is genetic variation so important?

10. Gamete Formation in Male and Female Animals involves Meiosis
1. Meiosis in males-spermatogenesis
A. Occurs in testes
B. produces four haploid sperm

11. Meiosis in females-Oogenesis
A. occurs in ovary
B. at the end of meiosis I, the cytoplasm divides unequally
1. Larger of the two cells becomes the egg.
2. Smaller cell is called a polar body
C. the larger cell undergoes meiosis II which results in unequal cell division
1. The larger cell is called the ovum
2. The smaller cell is a polar body.

13. Review Questions 9. How many sperm are produced from spermatogenesis?
10. How many eggs are produced from oogenesis?
11. What is a polar body?

14. Types of Asexual Reproduction
Budding
- unequal division
Ex. yeast

15. Budding - Hydra

16. Binary Fission-equal division of cytoplasm-paramecium and bacteria

17. What is this??

18. Spore formation- asexual in fungus. Ex : Bread mold

20. Regeneration- ability to grow back body parts

21. Regeneration Planarian California Black Worm
               
Planarian
California Black Worm

22. Asexual Reproduction: advantages and disadvantages
1. Produces many offspring in a short period of time.
2. Don’t need to waste time and energy finding a mate.
3. In a changing environment, they lack the ability to adapt.

23. Sexual Reproduction: advantages and disadvantages
1. Provides genetic variation.
2. More able to survive in a changing environment-evolution.
3. Need to find a mate.
4. Requires more time and energy

24. Sexual Selection

25. Why does the male peacock have a long, heavy tail?
Sexual Selection
Why does the male peacock have a long, heavy tail?

26. Sexual Selection
Humans select for certain traits too!

27. Review Question
12. Name three different types of asexual reproduction.
13. What are the advantages of asexual reproduction?
14. What are the advantages of sexual reproduction?