August Weismann

For the 19th-century New York politician, see Augustus Weismann.

Friedrich Leopold August Weismann (17 January 1834 – 5 November 1914) was a German evolutionary biologist. Ernst Mayr ranked him the second most notable evolutionary theorist of the 19th century, after Charles Darwin. Weismann became the Director of the Zoological Institute and the first Professor of Zoology at Freiburg.