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.
Biocoenosis
An ecosystem, originally defined by Tansley (1935), is a biotic community (or biocenosis) along with its physical environment (or "biotope"). In ecological studies, biocenosis is the emphasis on relationships between species in an area. These relationships are an additional consideration to the interaction of each species with the physical environment.