Charles Darwin’s theory of evolution hinges on natural selection, the idea that species survive by inheriting traits that allowed earlier generations to adapt to their environments.
In the 1930s, Theodosius Dobzhansky, a Soviet-born geneticist, advanced Darwin’s theory, showing how gene mutations drive this feat of biological engineering.
At the time, scientists assumed that all organisms in a species possessed identical genes. In his book “Genetics and the Origin of Species, Dobzhansky disproved this idea, showing how different populations of fruit flies bear distinctive markers.
A new species, he argued, is created when these populations begin mating exclusively with each other. The idea – and evolution as a whole – is often shunned by religious groups, which tout “intelligent design” from a higher power.
Dobzhansky, however, believed the two schools of thought could coexist.
“I am a creationist and an evolutionist,” he wrote in a 1973 essay. “Evolution is God’s, or Nature’s method of creation.”