Sinai Tschulok (1875-1945)-a pioneer of Cladistics.

Sinai Tschulok emigrated from the Ukraine to Switzerland, where he studied natural sciences, in particular biology. He founded and managed his own high school, which prepared students for entry to university-level education. This left him little time for research, which may explain why his work largely fell into oblivion. He did publish two influential books, however (Tschulok, S., 1910, Das System der Biologie in Forschung und Lehre, Gustav Fischer, Jena and Tschulok, S., 1922, Deszendenzlehre, Gustav Fischer, Jena), which were cited and commented upon favourably by both Walter Zimmermann and Willi Hennig. The most important point, in their opinion, was how Tschulok's explication of biological systematics had turned the "natural system" into a proof for the "Theory of Descent". The influence of Walter Zimmermann on Willi Hennig and the development of phylogenetic systematics is well known. Here some parts of Tschulok's writings are discussed that render him a pioneer in Cladistics. © The Willi Hennig Society 2009.