Proliferate-mitosis and proliferate-meiosis are processes of cell division in diploid cells. Mitosis happens in somatic cells and the daughter cell is identical to the parent cell, in that the daughter cell is a diploid cell, but in meiosis, you have a second division after the initial one. This is why meiosis is used in the formation of gametes instead of mitosis. In this second division, a phenomenon called chiasmata formation occurs, where homologous chromosomes switch bits of DNA, so that you have an entirely new and unique combination of genes in those chromosomes. This is what causes variation among organims that sexually reproduce.