Theodosius Grigorievich Dobzhansky was an American geneticist and evolutionary biologist. He was a central figure in the field of evolutionary biology for his work in shaping the modern synthesis and also popular for his support and promotion of theistic evolution as a practicing Christian. Born in the Russian Empire, Dobzhansky emigrated to the United States in 1927, aged 27.

Evolutionary biology is the subfield of biology that studies the evolutionary processes that produced the diversity of life on Earth. It is also defined as the study of the history of life forms on Earth. Evolution holds that all species are related and gradually change over generations. In a population, the genetic variations affect the phenotypes of an organism. These changes in the phenotypes will be an advantage to some organisms, which will then be passed on to their offspring. Some examples of evolution in species over many generations are the peppered moth and flightless birds. In the 1930s, the discipline of evolutionary biology emerged through what Julian Huxley called the modern synthesis of understanding, from previously unrelated fields of biological research, such as genetics and ecology, systematics, and paleontology.