1. Chapter 7 Meiosis and Sexual Reproduction
Know last chapter and the steps of mitosis, this will help tremendously with this chapter!!!
Section 1-Meiosis
Meiosis- A form of cell division that halves the number of chromosomes when forming specialized reproductive cells. As you know they are called gametes.

2. Meiosis-Starts with homologous chromosomes
Crossing-over-Occurs when portions of a chromatid on one homologous chromosomes are broken and exchanged with the corresponding chromatid portions of the other homologous chromosomes. During prophase I!!!!

3. Steps in meiosis!!!
Prophase 1-Chromosomes condense and nuclear envelop breaks down.
Metaphase 1-Pairs of homologous chromosomes are moved by the spindle fiber to the middle(or equator).
Anaphase 1-Homologous chromosomes separate. The chromatids do not separate at their centromeres. Still two chromatids. You will draw this later!!

4. Telophase 1-Individual chromosomes gather at each of the poles
Telophase 1-Individual chromosomes gather at each of the poles. Chromosomes do not replicate between meiosis I and meiosis II!!
Prophase 2-A new spindle forms around the chromosomes
Metaphase 2-Chromosome line up in the middle.
Anaphase 2-The centromeres divide, and the chromatids move to opposite poles
Telophase 2-Nuclear envelope forms around each set of chromosomes.

7. Meiosis and Gamete Formation
Spermatogenesis-The process by which sperm are produced in male animals.
Sperm-The four haploid cells change in form and develop a tail to become males gametes.
Oogenesis-The process by which gametes are produced in female animals.
Let’s look at Figure 3 in your book. Note the polar bodies in Oogenesis will more than likely die.
END OF SECTION 1, YEAH!!!
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8. Sexual Reproduction
Asexual reproduction-A single parent passes copies of all of its genes to its offspring. There is no fusion of haploid cells.
Clone-An organism that is genetically identical to its parent.
Sexual reproduction-Two parents form reproductive cells that have one-half the number of chromosomes.
The offspring have traits of both parents, but are not exactly like either parent.

9. Types of Asexual Reproduction, Genetic Diversity, Evolution of Sexual Reproduction
Fission-Amoebas reproduce by fission.
Budding and Fragmentation-

10. Genetic Diversity
Asexual reproduction is the simplest and most primitive method of reproduction, but sexual reproduction provides a powerful means of quickly making different combinations of genes.
Only diploid cells can repair certain kinds of chromosome damage, such as breaks in the DNA.

11. Sexual Life Cycles in Eukaryotes
Life cycle-The entire span in the life of an organism from one generation to the next.
Types of sexual life style
Haploid, diploid, or alteration of generations
Haploid life cycle-The zygote is the only diploid cell, and it undergoes meiosis immediately after it is formed.

12. Diploid Life Cycle
Adult individuals are diploid, each individual inheriting chromosomes from two parents.
Fertilization-The gametes (sperm and egg cells) join in this process. Results are diploid zygote.

13. Alteration of Generation
Sporophyte-The diploid phase in a life cycle that produces spores.
Spore-A haploid reproductive cell produced by meiosis that is capable of becoming an adult without fusing with another cell.
Gametophyte-The haploid phase that produces gametes by mitosis.

15. End of section 2