Editing August Weismann (section)

=== 1896–1910 ===
Weismann worked on the embryology of sea urchin eggs, and in the course of this observed different kinds of cell division, namely equatorial division and reductional division, terms he coined (''Äquatorialteilung'' and ''Reduktionsteilung'' respectively).

His ''germ plasm theory'' states that multicellular organisms consist of [[germ cell]]s containing heritable information, and [[somatic cells]] that carry out ordinary bodily functions. The germ cells are influenced neither by environmental influences nor by learning or morphological changes that happen during the lifetime of an organism, which information is lost after each generation. The concept as he proposed it was referred to as ''Weismannism'' in his day, for example in the book ''An examination of Weismannism'' by [[George Romanes]]<ref name="GJR"/> This idea was illuminated and explained by the rediscovery of [[Gregor Mendel]]'s work in the early years of the 20th century (see [[Mendelian inheritance]]).