Armenteras, D., González, T.M., Vergara, L.K., Luque, F.J., Rodríguez, N., Bonilla, M.A. 2016. A review of the ecosystem concept as a "unit of nature" 80 years after its formulation. Ecosistemas 25(1): 83-89. Doi.: 10.7818/ECOS.2016.25-1.12 Since the ecosystem was proposed as one of the basic units of nature, the use of the term has not only been restricted to academics, scientists or decision makers in the environmental sector, but has also permeated society and the public interest. It has become a benchmark for communication between different sectors of society, and is now a widely used word in contexts where it is important to understand how living things operate and interact with their environment. In the academic-scientific arena it has been proposed as a concept of organization, framework and central theory in ecology. Decision makers have tried to take the concept to a practical level or have highlighted functional aspects of it. The term ecosystem has been used to refer to spatially distinct units representing entities, which usually are taken into account for the activities of land zoning and planning or for the collection, management and protection of natural resources and associated environmental services. Further, the ecosystem has become part of common vocabulary to refer to specific natural sites important for society. The number of connotations used today is so wide that has resulted in inconsistent or sometimes confusing uses of the term. This paper presents a revision of the concept of ecosystem from peer reviewed literature and the analysis of its evolution over the last 80 years.