The organization of life extends beyond the individual organism to the biosphere, the zone of air, land, and water at the surface of the Earth where organisms exist. Individual organisms belong to a population, which is all the members of a species within a particular area. The populations of a community interact among themselves and with the physical environment (e.g., soil, atmosphere, and chemicals), thereby forming an ecosystem.
Sylvia S. Mader, Biology (10th ed., 2010), Ch. 1. A View of Life.