How are the outcomes of cell division by meiosis different from mitosis, and the significance to species?
Mitosis occurs only in somatic (non-reproductive) cells. A new copy of each chromosome is made, so a 2n cell becomes 4n. The new chromosomes then separate, the nucleus divides and half the chromosomes end up in each of 2 daughter cells which are 2n. Barring any errors in DNA replication or failure of the chromosomes in separating, you end up with 2 daughter cells identical to the parent cell you started with. Purposes – replacement of cells in multicellular organisms and in asexual reproduction. For species that reproduce asexually they are able to increase numbers very quickly and exploit the environment. Examples include unicellular organisms such as Amoeba, vegetative growth in many plants and insects with reproduce parthenogenetically (without males). Meiosis occurs only in the germ line cells involved in sexual reproduction. The process is as follows: DNA replication so that a 2n cell becomes 4n as in mitosis. In meiosis 1 the homologous chromosomes pair up (homologous chromosomes
