Ecosystem
The term ecosystem was first used in 1935 in a publication by British ecologist Arthur Tansley. Tansley devised the concept to draw attention to the importance of transfers of materials between organisms and their environment. 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". Tansley regarded ecosystems not simply as natural units, but as "mental isolates". Tansley later defined the spatial extent of ecosystems using the term ecotope.
Systems ecology
Deep ecology is an ideology whose metaphysical underpinnings are deeply concerned with the science of ecology. The term was coined by Arne Naess, a Norwegian philosopher, Gandhian scholar, and environmental activist. He argues that the prevailing approach to environmental management is anthropocentric, and that the natural environment is not only "more complex than we imagine, it is more complex than we can imagine." Naess formulated deep ecology in 1973 at an environmental conference in Budapest.