Theodosius
Dobzhansky (1900 - 1975)
Феодо́сий
Григо́рьевич Добржа́нский
The Ukrainian-born biologist was an early
proponent of the study of genetic variation in natural populations
as a means to understand evolution. After leaving the Soviet
Union, he went first to Cal Tech in southern California and then
to Columbia University in New York. he studied chromosomal
variation in Drosophila pseudoobscura, a wild relative of
D. melanogaster. His demonstration that frequencies of
different chromosomal arrangements within species varied according
to altitude, temperature, and humidity, and regularly cycled over
the seasons of the year, was the first clear evidence that genetic
variation was adaptive, as Darwin had predicted. His "Genetics
and the Origin of Species" (1937; 4th ed., 1970)
contributed the Genetics component of the Modern Synthesis.
His aphorism that "Nothing in biology
makes sense except in the light of evolution"
is widely quoted.