Paper short abstract:

Dobzhansky understood society in a biological register and brought politics into his scientific work. His study of tropical life particularly influenced his understanding of the biological and social. I explore his work in Brazil in a period of scientific and political reform.

Paper long abstract:

Dobzhansky worked in Brazil from 1943 to 1956 with the most genetically diverse species of Drosophila, the D.willistoni. Fascinated by tropical ecology, he thought of his Brazilian trips in light of Darwin's voyage onboard the Beagle. Yet, little is known about Dobzhansky's tropical research. While American scholars have overlooked Dobzhansky's work in Brazil, Brazilian scholars have focused on his role in the institutionalization of genetics in that country. As a result, we do not understand how Dobzhansky's Brazilian research fits with his genetics program that modernized Darwin's theory. I argue that said research was very important for the adaptationist programme of the Modern Synthesis. Based on Dobzhansky's correspondence, articles with Brazilian co-authors, and a chapter on "adaptive polymorphisms" in the 1951 edition of Genetics and the Origin of Species, I maintain that the richness of tropical life made it easier for Dobzhansky to see organic diversity as an adaptive response to environmental diversity. However, I open up the "tropics" for analysis by noting the ways in which Dobzhansky's views fit with, but also depart from, romanticized readings of the tropics by previous naturalists, including Humboldt, Wallace, and Darwin. I then discuss Dobzhasky's view of the adaptive nature of genetic variation vis-a-vis the contemporaneous work of the Brazilian sociologist Gilberto Freyre, wherein the Brazilian population adapted to the tropics through racial mixture. I pay particular attention to their shared concepts of 'plasticity' and 'adaptability' as the foundation of their optimism.