Theodosius Dobzhansky — Ukrainian Scientist born on January 25, 1900, died on December 18, 1975
Theodosius Grygorovych Dobzhansky ForMemRS was a prominent Ukrainian-born American geneticist and evolutionary biologist, and a central figure in the field of evolutionary biology for his work in shaping the unifying modern evolutionary synthesis. Dobzhansky was born in Ukraine, then part of the Russian Empire, and became an immigrant to the United States in 1927, aged 27 years old... (wikipedia)