Zoologist, born in Kempten, Germany. He studied at Berlin, and became professor of zoology at Harvard (1953-75). His early work was on the ornithology of the Pacific, leading three scientific expeditions to New Guinea and the Solomon Is (1928-30), but in his later career he was best known for his neo-Darwinian views on evolution, as developed in such books as Animal Species and Evolution (1963) and Evolution and the Diversity of Life (1976).