It's been 10 years now since the definition of ECOSYSTEM given by Ernest Callenbach first appeared in his “pocket-guide” called Ecology. The definition is provided below so that the reader of the SUSTAINABILITY definition will have the context of the meaning of ECOSYSTEM. Please read the definition of ECOSYSTEM below.
If you've taken a hike through a forest, you've been in a large ecosystem. However, within the forest we can mark off smaller ecosystems, like creeks or meadows, each with a characteristic set of SPECIES. Within an ecosystem, we always find organisms using PHOTOSYNTHESIS (or, in a few cases, chemical synthesis) to grow and produce food for other organisms, and DECOMPOSITION organisms recycling the basic elements of life. An ecosystem is capable of th complete cycling of the basic elements CARBON, NIROGEN, OXYGEN, PHOSPHORUS, and SULFUR. Within an ecosystem, nutrients rcycle from living organisms through organic wastes and pollutants back to new living organisms; ENERGY flows in (in the form of sunlight, wind, or water movement) and flows out (as heat).
Small ecosystems are nested within larger ecosystems and all of Earth's ecosystems taken together make up the BIOSPHERE/ECOSPHERE. There is some ... [to be compiled completely at a later time].
Robert "Roy" van de Hoek
Ecosystems are very complex and are beautiful too. This interesting and simple explanation of an ecosystem by Ernest Callenbach entices the reader to continue further