Every organism is influenced somehow by every part of its environment. An ecosystem is any place or time where organisms interact with their environment. Ecosystems can be divided into the life in the area and the area in which life exists. Biocoenosis is the life in the area and the biotope is the environment by which life is influenced. One form of interaction in the ecosystem is the food chain, a system moving energy and matter through organisms and the environment. A microecosystem is a small system like a fish with parasites. A mesoecosystem could refer to the coral reef in which the fish lives and a macroecosystem might be the area in which the coral reefs are located and how they interact.