Meiosis

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Meiosis 

Occurs in Gonads to form haploid Gametes so that when they come together at fertilisation you get a zygote which is diploid.It is also important in bringing about variation in  a species due to the processes of crossing over , random assortment and random fertilisation and mutations.

There are two divisons and the second is very similar to that of mitosis.

During Prophase 1 

The spindle fibres start to form and homologous chromosomes pair up to form a bivalent made up of two chromosomes( these occur anywhere in the cell. . The chromosomes come so close that at some points they cross over one another and exchange information _ the points at which this occurs are called chiasmata and the process is called crossing over. The nuclear membrane disintigrates and the nucleolus disappears at the end of this stage. 

Metaphase 1

The bivalents go to the equator of the cell and this is when random assortment occurs - not all of dads chromosomes end up on one side of the…

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