In 1935, Arthur Tansley coined the term ecosystem.  An ecosystem relates the biotic and abiotic elements of a certain area and the relationships between them.

The characteristics of an ecosystem depend on climate, topography, the nature of the soil, and the living organisms that inhabit it.  Each of these factors consists of many other factors, and together they determine the nature of the ecosystem.

Often, the area referred to by an ecosystem is a common and recognizable environmental system.  It could be a watershed, a wetland, a mash, a swap, a lake or river, or one of many other features of the natural world.

The living creatures in an ecosystem are linked together through a food chain.  Through the food chain, energy and material pass from one creature to the next.  Along the way, however, much of the energy is lost.

Materials, unlike energy, are usually recycled in a food chain.  Certain nutrients may follow through the nutrient cycle, appearing in a different living thing at each step of the process.

One type of food chain consists of plants and animals that consume each other to continue life.  This system, on which humans are chiefly dependent, is called a grazing food chain.

The other type of food chain is one in which living organisms die and decompose.  Things such as fungi and bacteria break down and metabolize dead organic matter.

After a while, an ecosystem will begin to stabilize, reaching dynamic equilibrium.  At this stage, the ecosystem may be referred to as a habitat, and will contain a somewhat constant group of interrelated creatures.