Energy flow (ecology)

A food pyramid and a corresponding food web, demonstrating some of the simpler patterns in a food web.

Energy flow is the flow of energy through living things within an ecosystem.^[1] All living organisms can be organized into producers and consumers, and those producers and consumers can further be organized into a food chain.^[2]^[3] Each of the levels within the food chain is a trophic level.^[1] In order to more efficiently show the quantity of organisms at each trophic level, these food chains are then organized into trophic pyramids.^[1] The arrows in the food chain show that the energy flow is unidirectional, with the head of an arrow indicating the direction of energy flow; energy is lost as heat at each step along the way.^[2]^[3]

The unidirectional flow of energy and the successive loss of energy as it travels up the food web are patterns in energy flow that are governed by thermodynamics, which is the theory of energy exchange between systems.^[4]^[5] Trophic dynamics relates to thermodynamics because it deals with the transfer and transformation of energy (originating externally from the sun via solar radiation) to and among organisms.^[1]

^ ^a ^b ^c ^d Lindeman RL (1942). "The Trophic-Dynamic Aspect of Ecology" (PDF). Ecology. 23 (4): 399–417. Bibcode:1942Ecol...23..399L. doi:10.2307/1930126. JSTOR 1930126. Archived from the original (PDF) on 2017-03-29. Retrieved 2020-12-04.
^ ^a ^b Briand F, Cohen JE (November 1987). "Environmental correlates of food chain length". Science. 238 (4829). New York, N.Y.: 956–60. Bibcode:1987Sci...238..956B. doi:10.1126/science.3672136. PMID 3672136.
^ ^a ^b Vander Zanden MJ, Shuter BJ, Lester N, Rasmussen JB (October 1999). "Patterns of Food Chain Length in Lakes: A Stable Isotope Study". The American Naturalist. 154 (4): 406–416. doi:10.1086/303250. PMID 10523487. S2CID 4424697.
^ Sharma JP (2009). Environmental studies (3rd ed.). New Delhi: University Science Press. ISBN 978-81-318-0641-8. OCLC 908431622.
^ Van Ness HC (1969). Understanding thermodynamics (Dover ed.). New York: Dover Publications, Inc. ISBN 978-1-62198-625-6. OCLC 849744641.

[Lindemanm0©_1942-1] Lindeman RL (1942). "The Trophic-Dynamic Aspect of Ecology" (PDF). Ecology. 23 (4): 399–417. Bibcode:1942Ecol...23..399L. doi:10.2307/1930126. JSTOR 1930126. Archived from the original (PDF) on 2017-03-29. Retrieved 2020-12-04.

[Briand_1987-2] Briand F, Cohen JE (November 1987). "Environmental correlates of food chain length". Science. 238 (4829). New York, N.Y.: 956–60. Bibcode:1987Sci...238..956B. doi:10.1126/science.3672136. PMID 3672136.

[Vander_Zanden_1999-3] Vander Zanden MJ, Shuter BJ, Lester N, Rasmussen JB (October 1999). "Patterns of Food Chain Length in Lakes: A Stable Isotope Study". The American Naturalist. 154 (4): 406–416. doi:10.1086/303250. PMID 10523487. S2CID 4424697.

[4] Sharma JP (2009). Environmental studies (3rd ed.). New Delhi: University Science Press. ISBN 978-81-318-0641-8. OCLC 908431622.

[5] Van Ness HC (1969). Understanding thermodynamics (Dover ed.). New York: Dover Publications, Inc. ISBN 978-1-62198-625-6. OCLC 849744641.

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