query: Who first defined ecosystems?
passage: Ecosystem
The term ecosystem was first used in 1935 in a publication by British ecologist Arthur Tansley.[fn 1][7] Tansley devised the concept to draw attention to the importance of transfers of materials between organisms and their environment.[8] He later refined the term, describing it as "The whole system, ... including not only the organism-complex, but also the whole complex of physical factors forming what we call the environment".[9] Tansley regarded ecosystems not simply as natural units, but as "mental isolates".[9] Tansley later defined the spatial extent of ecosystems using the term ecotope.[10]
passage: William Emerson Ritter
Ritter initiated and shaped the Marine Biological Association of San Diego (now Scripps Institution of Oceanography of UC San Diego) and the American Society for the Dissemination of Science (now the Society for Science and the Public and Science News). Innovative and entrepreneurial, with a deep desire for human service, he worked tirelessly to educate people in science thinking. He was the first biologist to propose a theory of systems, and seems to be the originator of the term organicism for biological purposes.