An ecosystem consists of all the living and nonliving things that occur together within a particular area. An ecosystem can be small, such as a family garden, or large, such as the Amazon rainforest. It may be terrestrial, such as a grassland, or aquatic, such as a pond or a coral reef. All of the organisms living within an ecosystem rely on each other for their survival.
An ecosystem includes abiotic, or nonliving, components, such as minerals, climate, soil, water, and sunlight. It also includes biotic, or living, elements, such as plants, animals, fungi, protists, and bacteria. The living and nonliving parts of an ecosystem are linked together by two major forces: the flow of energy through the ecosystem and the cycling of nutrients within the ecosystem. (Encyclopedia Britannica Source)