meiosis

Oscar Hertwig (1849-1922)

Term:  meiosis

Origin: Anc Greek μείον/meion(=less) + -οσις/osis(=process)  

Coined: by Oscar Hertwig, in 1876 who was the first to discover the process of meiosis inside the eggs of a sea urchin. The sea urchin is transparent due to its small size, finely divided yolk, and its lack of a membrane. Because of this, Hertwig was able to observe the spermatozoa as they entered the egg and fused with its nucleus five to ten minutes later. Most importantly, however, Hertwig found that only one spermatozoon was required to fertilize an egg, and that once one spermatozoon entered the egg, the egg formed a vitelline membrane blocking any other spermatozoa from entering.  The significance of meiosis for reproduction and inheritance, however, was described only in 1890 by German biologist Ausust Weismann (1834-1914).  However, it was in 1911 that Thomas Hunt Morgan, a geneticist, realized the crossover process in anaphase I. This was evidence that proved genes were actually on chromosomes. The term meiosis was coined finally by J.B Farmer and J.B Moore in 1905.

Definition:

The process of eukaryotic cell division that reducing the number of chromosomes from diploid to haploid. Meiosis is consisting of chromosome conjugation and two cell divisions, leading to gamete formation.