6-3 Meiosis

- Sexual Reproduction allows genetic inforrmation to be swapped from different individuals from generation to generation in order for the best genes to succeed in a particular environment.

- Meiosis allows genes to cross-over from oone chromosome to another in order to increase genetic variation.

- Meiosis consists of two nuclear divisionss with eight stages

- Meiosis I

1. ) Prophase I - similar to prophase in Mitosis except portions of a chromatid on homologous chromosome are exchanged with the corresponding portions of a chromatid on another homologous chromosome.
   
   
2. ) Metaphase I - similar to metaphase in Mitosis
   
   
3. ) Anaphase I - Chromatids do not separate as in Mitosis, instead homologous pairs of chromosomes are separated.
   
   
4. ) Telophase I - since the pairs of homologous chromosomes were separated the new nuclear envelopes now contain only one set (haploid) of chromosomes.

- Meiosis II - the stages of meiosis II are the same as Mitosis except the cells have only one set of chromosomes (haploid)

1. ) Prophase II - Nuclear envelope breaks down, spindle fibers form
   
   
2. ) Metaphase II - chromosomes line up
   
   
3. ) Anaphase II - chromatids are pulled towards opposite sides.
   
   
4. ) Telephase II - new nuclear envelopes form