Étienne Geoffroy Saint-Hilaire

Appointed professor of vertebrate zoology at the Muséum National d'Histoire Naturelle at age twenty-one in 1793, Geoffroy accompanied Napoleon to Egypt in 1798, collecting mummified animals and discovering the Nile lungfish Polypterus.

In his 1818 Philosophie anatomique, he argued that all animals share a single fundamental anatomical body plan (unity of type), modified over geological time by environmental pressures and embryonic development. His famous public debates against Cuvier's fixist theory in 1830 electrified Europe and profoundly influenced Johann Wolfgang von Goethe and Charles Darwin.