A ll the living and nonliving things that interact in aparticular area make up an ecosystem. Organisms live in aspecific place within an ecosystem. An organism obtains food,water, shelter, and other things it needs to live, grow, andreproduce from its surroundings.The place where an organismlives and that provides the things the organism needs is calledits habitat.An organism interacts with both the living and nonlivingthings in its environment. The living parts of an ecosystem arecalled biotic factors.ll the different populations that live together in anarea make up a community. The smallest unit of organization isa single organism, which belongs to a population of othermembers of its species. The population belongs to a communityof different species. The community and abiotic factorstogether form an ecosystem.