Étienne Geoffroy Saint-Hilaire (1772–1844), naturalist, established the principle of ‘unity of composition’. A colleague of Lamarck’s, he expanded and defended the latter’s evolutionary theories, arguing for the underlying unity of the design of organisms, and the possibility of the transmutation of species in time. He amassed evidence for his claims through research in comparative anatomy, paleontology, and embryology. For several decades, Geoffroy played a fiery part in the cross-English Channel debate on the biology and classification of the Australian platypus.
Updated 2018
