Lev Semyonovich Berg (also known as Leo S. Berg) (Russian: Лев Семёнович Берг; March 14, 1876, Bender - December 24, 1950, Leningrad) was a leading Soviet geographer, biologist and ichthyologist who served as President of the Soviet Geographical Society between 1940 and 1950. He also developed his own evolutionary theory as opposed to the theories of Darwin and Lamarck.