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I need to know the stages of meiosis and why it's important to know them.

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3 Answers

Meiosis is very similar to mitosis, with a few exceptions:

1- Mitosis can occur in all cells that ARE NOT a sex cell (like egg or sperm), whereas meiosis ocurs only in sex cells

2- Meiosis Produces four cells from 1 instead of 2 (like mitosis)

3- Meiosis produces HAPLOID cells instead of DIPLOID cells

4- During PROPHASE I of meiosis, a unique process occurs called crossing over occurs, where homologous chromosomes may exchange portions of their chromatids and produce unique NEW genetic arrangements.

The 4 differences above are WHY the steps of Meiosis ARE IMPORTANT. The process produces sex cells, which are haploid and may also produce NEW UNIQUE genetic combinations.  These unique arrangement are one of the mechanisms of evolution.

The stages are 

1-Prophase I

2- Metaphase I

3- Anaphase I

4- Telophase I

5- Prophase II

6- Metaphse II

7- Anaphase II and

8- Telophase II

Meiosis, very easy to confuse with Mitosis.  I have always had my students go to this excellent site to see what is happening: http://www.cellsalive.com/meiosis.htm.  This is an excellent animation. 

Remember that Meiosis is like Mitosis because it goes through all the stages (& in the same order) but it goes through interphase only once.  Now why that is important?

 

The best way to remember the stages of meiosis is probably to use a diagram. Here's a convenient one: http://upload.wikimedia.org/wikipedia/commons/5/54/Mei osis_diagram.jpg

The different stages are important because there are different processes occuring within each stage, and they correlate to each other. For example, whether you're talking about Telophase in Mitosis or Telophase I or Telophase II in meiosis, they refer to the same process, the forming of two separate neuclei in the cell and getting ready to split. Giving it a name helps people refer to the process without saying "that one thing that happens at this time" and being vague.