August Weismann

August Weismann was a German evolutionary biologist, born in Frankfurt am Main on January 17, 1834, and dead in Freiburg im Breisgau on November 5, 1914. He studied medicine before turning fully toward zoology and became one of the strongest early defenders of Darwin’s theory of natural selection.

He is best remembered for the germ-plasm theory, which argued that hereditary information is passed through reproductive cells rather than being shaped by changes acquired during an organism’s life. That idea challenged the inheritance of acquired characteristics and helped lay important groundwork for later genetics.

Weismann also taught for many years at the University of Freiburg and earned a reputation as one of the major evolutionary theorists of the nineteenth century. Even where later biology revised his views, his work remained a crucial step in the development of modern thinking about heredity and evolution.