2. –If both parents replicated cells using mitosis, a child would receive 46 chromosomes from dad & 46 from mom given a grand total of…? –92! (Way too many) –So…if dad could give 23 + 23 from mom = 46! (Bingo!)

4.  Binary Fission  Budding  Fragmentation

5. Better when the environment is not favorable or becomes unstable

6. Meiosis

7. Def: 2 successive cell divisions that produce gametes What does that mean? –Successive  one right after the other –Gametes  a haploid reproductive cell, either an egg or a sperm –Haploid  containing only 1 of every chromosomes (n) –Diploid  containing 2 of every chromosome (2n)

8. Some More Vocabulary Body Cells –AKA  somatic cells –Ex  skins cells, nerve cells, blood cells pairs –Diploid  46 chromosomes (23 pairs) Sex Cells –AKA  germ cells –Ex  egg & sperm single –Haploid  23 chromosomes (all single) Q: A mutation in which type of cell would be worse?

9. Chromosome Number in Mitosis

10. Meiosis = 2 Mitosis P 1 M 1 A 1 T 1  P 2 M 2 A 2 T 2 With a few slight differences!

11. Prophase I Metaphase I Anaphase I Telophase I Meiosis = 1 st Division Prophase 1  Crossing Over Metaphase 1  chromosomes line up randomly 2 by 2 forming a tetrad (4 across)tetrad Anaphase 1  homologous chromosomes are pulled to opposite poles (sister chromatids do not separate!)

12. Crossing Over

13. Single Chromosomes line up Sister Chromatids are pulled apart Prophase 2Metaphase 2 Anaphase 2Telophase 2 Meiosis II 2nd Division

14.  Cells divide twice! (Mitosis divide only once)  End result is 4 different cells instead of 2 genetically identical cells!  Chromosome number is cut in half! › 2n (diploid)  n (haploid) = Meiosis › 2n  2n = Mitosis  Crossing Over!

15. The purpose of meiosis is…? To produce gametes which are necessary for sexual reproduction. Allows for new mixtures of combinations  called genetic recombination VARIATION!