Biologist. First formulated endosymbiotic theory, stating that eukaryotic organisms began as prokaryotes that were engulfed by other prokaryotes and continued to live in a symbiotic relationship. Now working on the Gaia hypothesis (her spelling), which considers the entire earth as an organism.

She received her Ph.D. from the University of Calfornia, Berkeley in 1963 and is currently a Distinguished University Professor at the University of Massachusetts, Amherst.