Arthur Tansley

Tansley introduced the term ecosystem into ecology in his 1935 paper The Use and Abuse of Vegetational Concepts and Terms, defining it as the whole system of organisms together with the physical factors of their environment, treated as one interacting unit rather than organisms and environment studied separately; the word itself was suggested to him by the botanist Arthur Roy Clapham at his request. Tansley founded the British Ecological Society in 1913, the first such society in the world, and its journal, and later chaired Britain's first Nature Conservancy, shaping how ecology became organized as a professional science rather than a branch of natural history.