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trophic level

noun, Ecology
1.
any class of organisms that occupy the same position in a food chain, as primary consumers, secondary consumers, and tertiary consumers.
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Based on the Random House Dictionary, © Random House, Inc. 2014.
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Examples for trophic level
  • The term trophic level refers to an organism's position in a food chain.
  • Plant matter in an ecosystem makes up the first trophic level and thus are known as primary producers.
trophic level in Science
trophic level  
Any of the sequential stages in a food chain, occupied by producers at the bottom and in turn by primary, secondary, and tertiary consumers. Decomposers (detritivores) are sometimes considered to occupy their own trophic level. ◇ The rate at which energy is transferred from one trophic level to the next is called the ecological efficiency. Consumers at each level convert an average of only about 10 percent of the chemical energy in their food to their own organic tissue. Since plants can only convert approximately 1 percent of incident sunlight into chemical energy at the lowest trophic level (the bottom of the food chain), the percentage of the energy in incident sunlight that reaches a tertiary consumer is about 0.0001.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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Encyclopedia Article for trophic level

step in a nutritive series, or food chain, of an ecosystem. The organisms of a chain are classified into these levels on the basis of their feeding behaviour. The first and lowest level contains the producers, green plants. The plants or their products are consumed by the second-level organisms-the herbivores, or plant eaters. At the third level, primary carnivores, or meat eaters, eat the herbivores; and at the fourth level, secondary carnivores eat the primary carnivores. These categories are not strictly defined, as many organisms feed on several trophic levels; for example, some carnivores also consume plant materials or carrion and are called omnivores, and some herbivores occasionally consume animal matter. A separate trophic level, the decomposers or transformers, consists of organisms such as bacteria and fungi that break down dead organisms and waste materials into nutrients usable by the producers

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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