What is an Ecosystem?
The word ecosystem was first used in 1935, by a British scientist, Arthur Tansley. Tansley was describing systems of integrated living things, plus the non-living things that complete their environment—systems that are more or less self-perpetuating as long as there are no major changes in climate, or natural disasters.
Ecosystems are recognizable places with specific characteristics: a lake is an ecosystem that includes all of the species living in it, plus the water, the lake bottom, and minerals and nutrients dissolved or suspended in the water. A swamp is an ecosystem including everything that exists and lives in the swamp. Other types of ecosystems include deserts, polar ice, prairies, forests, tundra, and continental shelves. There are many more examples.
Artificial collections of living things that people create, such as aquariums and biodomes are ecosystems too, except that they’re not usually self-perpetuating. These small ecosystems, constructed in places where they wouldn’t ordinarily exist, must be controlled and managed by people in order to function,
Energy Flow in Ecosystems
One of the reasons that ecosystems work is that energy is constantly flowing from one thing another. Living things prey on each other, produce waste products, die, and are consumed in turn by other living things. Energy from the sun replaces energy that is lost in the process of energy flow, and ideally, there is a sort of equilibrium so that the total amount of energy remains constant in the ecosystem and the needs of every living thing are met.
Recycling in Ecosystems
Energy is not the only thing that gets passed around in an ecosystem. Other things necessary to life, such as carbon, nitrogen, and other elements, get recycled by the waste products and decay of living things as they are produced, flourish, and then die. These elements don’t change over time; they just move around, recycling through living things and the environment.
Ecosystem and Balance
Balance in an ecosystem is the equilibrium that exists when the needs of all living things are being met and conditions remain the same for long periods of time. Because everything in an ecosystem contributes something, changes to species, climate, or physical features can destroy the balance and significantly change the ecosystem. Sometimes the entire ecosystem collapses, many species die out, and new ones take their place. This is a particular concern when pollution or exploitation of the natural environment wipe out species.
Related articles:
Sources:
10 Minute Ecologist. Janovy, John Jr. New York: St. Martin’s Press, 1997.
Ecology and Environment: The Cycles of Life. Morgan, Sally. New York: Oxford University Press, 1995.
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