The process of meiosis is a form of cell division that produces reproductive cells, also known as gametes. This process involves two successive cell divisions that produce half the number chromosomes in the new cells.
Meiosis occurs in both single and multi-cellular organisms, including plants, fungi and animals. Typically, the two divisions are referred to as meiosis I and meiosis II. During meiosis I, genetic material is exchanged between homologous chromosomes. These chromosomes separate to form daughter cells, which have half the number of chromosomes as the original cells. Sister chromatids remain attached at the end of meiosis I.
In meiosis II, the cells that were produced in meiosis I are divided. The sister chromatids detach and are separated into daughter cells. These cells become the reproductive cells.
While the process was observed at earlier times, German biologist August Weismann was the first to note the process that meiosis played with reproduction in 1890. The term meiosis was first used in 1905.
This process is similar to mitosis, which is another form of cell division. The difference is that mitosis results in the formation of two daughter cells that are genetically identical. It is also only used in single-celled organisms.