The ecosystem has been a key concept in the development of modern ecology.However, today it is widely misunderstood and misused.The development of the ecosystem concept coincides with a period of change in the approach to this term, from Clementsian holism, which predominated in the first half of the twentieth century, to the reductionism dominant today.This concept emerges as a theoretical argument in the context of the theory of ecological succession as a clear Tansley´s refutation of Clementsian ontology.The purpose of this paper is to present a review of the origin of the ecosystem concept.