The importance of meiosis is that it enables genetic diversity. Unlike the asexual form of cellular division, mitosis, meiosis allows chromosome pairs with the same genes, called homologous chromosomes, to exchange pieces in a process called recombination. This enables chromosome pieces from the female parent to combine with those of the male parent.
The advantage to meiosis is that the genetic diversity it produces among sexual organisms can help make a species population more stable by producing a wider variety of traits for the process of natural selection to act upon. Meiosis relies upon processes that are similar to those occurring during mitosis during cell division, but several, such as recombination, occur only in meiosis.