Why is meiosis necessary for sexual reproduction ?
All human cells contain 23 pairs of chromosomes. The egg, oocyte, only contains one set of 23 chromosomes. As compared to mitosis where the nucleus duplicates itself, the process of meiosis creates two separate cells each with 23 chromosomes. The main cell contains most of the protoplasm. The other is very small and contains the remainder 23 chromosomes. This other cell is called the polar body and is of no use in reproduction. When the oocyte is fertilized with sperm, it receives 23 chromsomes from the male. The result is a nucleus that ultimately forms into 2 pairs of 23 chromosomes.
