ABSTRACT
Ecosystem is the fundamental unit of ecological studies. An ecosystem has both non-living (abiotic) and living (biotic) components. The ultimate source of energy for ecosystems is the sun. Green plants, also called primary producers, can fix part of the solar energy to manufacture food. Energy from producers is transferred through successive levels of consumers such as herbivores and carnivores, also termed as primary and secondary consumers. When producers and consumers die, they are acted upon by decomposers. The functional properties of ecosystems include energy flow, which is one-way and with progressive reduction at each point of transfer. On the contrary, movement of materials or nutrients is cyclic. Ecosystems also undergo development and evolution through a process called ecological succession, culminating through successive intermediate (seral) stages in a climax community. Species diversity is another functional attribute of ecosystems. Different ecosystems such as forests, deserts, and water bodies, while sharing several fundamental features, also reveal unique characteristics of their own.
