Theodosius Dobzhansky

Born on January 25, 1900, in Nemirov in the Russian Empire, now Nemyriv, Ukraine, he studied biology in Kyiv and began his early research on insects before moving to the United States in 1927. There he joined the great wave of researchers transforming genetics into a modern science.

Working especially with fruit flies, he became one of the central figures in the modern evolutionary synthesis, the movement that connected Mendelian genetics with Darwinian evolution. His 1937 book Genetics and the Origin of Species is widely remembered as a landmark, helping scientists explain how small genetic changes within populations could lead to large-scale evolutionary change over time.

He later taught and carried out research at major institutions including Columbia University, the Rockefeller Institute, and the University of California, Davis. Beyond the lab, he was known for writing about science in a broad, thoughtful way, and he is still often quoted for the line that nothing in biology makes sense except in the light of evolution.