The Basic of EcosystemNo organism lives in isolation. To be sustained, life requires continual inputs of energy and particular types of matter such as carbon dioxide, water, nitrogen and various mineral elements. For most organism, the ultimate source of energy is sunlight, captures in living matter by photosynthesis.
Earth is in the truest sense of the word a spaceship – there is a fixed supply of matter that must be sustain us for a very long journey, hence any given molecule of water or atom of nitrogen , carbon, oxygen or other essential element must be reused many times.
In other words, it must be cycled.
Cycling may take various forms. Water is cycled from ocean to land and back again, the entire process powered by sunlight.
Carbon is passed from organism though feeding and is eventually released back into the atmosphere as carbon dioxide where it once again is used by green plants to capture solar energy.
Nitrogen, phosphorus and other elements necessary to sustain life are also passed from organism to organism and in this way are cycled from the old to the new, permitting life to be continually renewed.
Without this renewal evolution not be possible and life as we know it would not exists.
No single species is capable of capturing energy and simultaneously cycling matter. Thus, living things are always found grouped together in communities the include species capable of capturing energy (in most cases green plants) and species that obtain their energy and the matter that composes their bodies by consuming in one fashion or another, the tissues of the other organisms.
Such a community is not simply an aggregation of bodies like travelers thrown together on an airline; rather, it is a coherent group that is tied together by interaction with one another and their environment.
A community of interacting species, taken together with the physical environment within which it exists and with which the species composing the community also interact, is an ecosystem.
The Basic of Ecosystem
