Significance of Meiosis

Meiotic division is what produces the gametes (or spores, in plants) needed for sexual reproduction, and its significance follows directly from what it achieves. If meiosis did not take place, the chromosome number of a species would double, or even quadruple, with every generation, since fertilisation itself combines the chromosome sets of two gametes — this uncontrolled increase would very quickly lead to abnormal, non-viable forms (monstrosities). It is the combined action of meiosis (which halves the chromosome number in gametes) and fertilisation (which restores the diploid number) that keeps the chromosome number of a given species constant across generations. …