ENERY FLOW THROUGH AN ECOSYSTEM
Ecosystems maintains themselves by cycling energy and nutrients obtained from external sources. At the first tropic level, primary producers (plants, algae, and some bacteria) use solar energy to produce organic plant material through photosynthesis. Herbivores – animals that feed solely on plants – make up the second trophic level.
Predators Activity in Food Chain
Predators that eat herbivores comprise the third trophic level; if larger predators are present, they represent still higher trophic levels. Organisms that feed at several trophic levels (for example, grizzly bears that eat berries and salmon) are classified at the highest of the trophic levels at which they feed.
Decomposers
Decomposers, which include bacteria fungi, molds, worms, and insects, break down wastes and dead organisms and return nutrients to the soil.
Decomposers process large amounts of organic material and return nutrients to the ecosystem in inorganic form, which is then taken up again by primary producers. Energy is not recycled during decomposition, but rather is released, mostly as heat.
Trophic Level in Food Chain
On average about 10 percent of net energy production at one trophic level is passed on to the next level. Processes that reduce the energy transferred between trophic levels include respiration, growth and reproduction, defecation, and non predatory death (organisms that die but are not eaten by consumers).
Nutritional Quality
The nutritional quality of material that is consumed also influences how efficiently energy is transferred, because consumers can convert high-quality food sources into new living tissue more efficiently than low-quality food sources.
The low rate of energy transfer between trophic levels makes decomposers generally more important than producers in terms of energy flow.
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