What are Ecosystems? Ecological Society of America 02.01.01 An ecosystem is a community of animals and plants interacting with one another and with their physical environment. Ecosystems include physical and chemical components, such as soils, water, and nutrients that support the organisms living within them. These organisms may range from large animals and plants to microscopic bacteria. Ecosystems include the interactions among all organisms in a given habitat. People are part of ecosystems. The health and well being of human populations depends upon the services provided by ecosystems and their components - organisms, soil, water, and nutrients. Prepared by   The Ecological Society of America   1707 H Street, NW, Suite 400, Washington, DC 20006   ©2001 The Aurora Collection, Inc. All Rights Reserved. Site Development by: Interactive Multimedia. Inc.