Ecosystem
An ecosystem (or ecological system) is a large community of living organisms (plants, animals and microbes) in a particular area.[2] The living and physical components are linked together through nutrient cycles and energy flows.[3] Ecosystems are of any size, but usually they are in specific places.
Each ecosystem has its own community. An aquarium community, for example, can have small fish and other organisms. A desert community may have cacti, small snakes, and scorpions. A pond community can have frogs, insects, snakes, and plants, and a forest community may have rabbits, foxes and pine trees. The species in a community are divided into populations according to the particular habitats and ecological niches in the ecosystem.
Energy
Ecosystems are stable, but changeable. They react to major changes in the environment, especially climate changes. For example, the major rainforests have lasted for a long time (perhaps 50 million years or more in some cases). As the rainfall and temperature changes, they change. We know that the Amazon rainforest shrank in size during ice ages, and expanded in the warmer periods.
Primary production
What drives all ecosystems is the primary production. Primary production is the production of organic matter from inorganic carbon sources. This happens through photosynthesis. It drives the carbon cycle, which influences global climate via the greenhouse effect.
Through the process of photosynthesis, plants capture energy from sunlight and use it to combine carbon dioxide and water to produce carbohydrates and oxygen. The photosynthesis carried out by all the plants in an ecosystem is called the gross primary production (GPP).[4] About 48–60% of the GPP is consumed in plant respiration. The rest is known as the net primary production (NPP).[4] Total photosynthesis is limited by a range of environmental factors. These include the amount of light available, the amount of leaf area a plant has to capture light (shading by other plants limits photosynthesis), the supply of carbon dioxide and water, and suitable temperatures for carrying out photosynthesis.[4]
Types
Some of the major types of ecosystem:
- Aquatic ecosystem
- Marine ecosystem
- Freshwater ecosystem
- Terrestrial ecosystem
Ecosystem Media
Flora of Baja California desert, Cataviña region, Mexico
Global oceanic and terrestrial phototroph abundance, from September 1997 to August 2000. As an estimate of autotroph biomass, it is only a rough indicator of primary production potential and not an actual estimate of it.
Sequence of a decomposing pig carcass over time
Biological nitrogen cycling
Loch Lomond in Scotland forms a relatively isolated ecosystem. The fish community of this lake has remained stable over a long period until a number of introductions in the 1970s restructured its food web.
Spiny forest at Ifaty, Madagascar, featuring various Adansonia (baobab) species, Alluaudia procera (Madagascar ocotillo) and other vegetation
A hydrothermal vent is an ecosystem on the ocean floor. (The scale bar is 1 m.)
Related pages
References
- ↑ Hatcher, Bruce Gordon (1990). "Coral reef primary productivity: a hierarchy of pattern and process". Trends in Ecology and Evolution. 5 (5): 149–155. doi:10.1016/0169-5347(90)90221-X. PMID 21232343.
- ↑ Molles, Manuel C. 1999. Ecology: concepts and applications. Boston: WCB/McGraw-HIll. ISBN 0-07-042716-X
- ↑ Odum E.P. 1971. Fundamentals of ecology. 3rd ed, New York: Saunders. ISBN 0534420664
- ↑ 4.0 4.1 4.2 Chapin F.S; Matson P.A. & Mooney H.A. 2002. Principles of terrestrial ecosystem ecology. New York: Springer, 97–104. ISBN 0-387-95443-0