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Food chain

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Title: Food chain  
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Subject: Ecological pyramid, Biomass (ecology), Energy flow (ecology), Fishing down the food web, Marine pollution
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Food chain

Food chain in a Swedish lake. Osprey feed on northern pike, which in turn feed on perch which eat bleak that feed on freshwater shrimp.

A food chain is a linear sequence of links in a polyphagous network of feeding relations are aggregated into trophic species and the chain only follows linear monophagous pathways. A common metric used to quantify food web trophic structure is food chain length. In its simplest form, the length of a chain is the number of links between a trophic consumer and the base of the web and the mean chain length of an entire web is the arithmetic average of the lengths of all chains in a food web.[1][2]

Food chains were first introduced by the African-Arab scientist and philosopher Al-Jahiz in the 9th century and later popularized in a book published in 1927 by Charles Elton, which also introduced the food web concept.[3][4][5]

Food chain length

This food web of waterbirds from Chesapeake Bay is a network of food chains

Food chains are directional paths of trophic energy or, equivalently, sequences of links that start with basal species, such as producers or fine organic matter, and end with consumer organisms. [6]:370

The food chain's length is a ecological structure that increases in value counting progressively through the linkages in a linear fashion from the lowest to the highest trophic (feeding) levels.[7] Food chains are often used in ecological modeling (such as a three species food chain). They are simplified abstractions of real food webs, but complex in their dynamics and mathematical implications.[2] Ecologists have formulated and tested hypotheses regarding the nature of ecological patterns associated with food chain length, such as increasing length increasing with ecosystem size, reduction of energy at each successive level, or the proposition that long food chain lengths are unstable.[7] Food chain studies have had an important role in ecotoxicology studies tracing the pathways and biomagnification of environmental contaminants.[8]

Food chains vary in length from three to six or more levels. A food chain consisting of a flower, a frog, a snake and an owl consists of four levels; whereas a food chain consisting of grass, a grasshopper, a rat, a snake and finally a hawk consists of five levels. deep sea, food chains centered around hydrothermal vents and cold seeps exist in the absence of sunlight. Chemosynthetic bacteria and archaea use hydrogen sulfide and methane from hydrothermal vents and cold seeps as an energy source (just as plants use sunlight) to produce carbohydrates; they form the base of the food chain. Consumers are organisms that eat other organisms. All organisms in a food chain, except the first organism, are consumers.

See also

References

  1. ^ Briand, F.; Cohen, J. E. (1987). "Environmental correlates of food chain length.".  
  2. ^ a b Post, D. M.; Pace, M. L.; Haristis, A. M. (2006). "Parasites dominate food web links". Proceedings of the National Academy of Sciences 103 (30): 11211–11216.  
  3. ^ Elton, C. S. (1927). Animal Ecology. London, UK.: Sidgwick and Jackson.  
  4. ^ Allesina, S.; Alonso, D.; Pascal, M. "A general model for food web structure.".  
  5. ^ Egerton, F. N. (2007). "Understanding food chains and food webs, 1700-1970". Bulletin of the Ecological Society of America 88: 50–69.  
  6. ^ Martinez, N. D. (1991). "Artifacts or attributes? Effects of resolution on the Little Rock Lake food web". Ecological Monographs 61 (4): 367–392.  
  7. ^ a b Vander Zanden, M. J.; B. J., Shuter; Lester, N.; Rasmussen, J. B. (1999). "Patterns of food chain length in lakes: A stable isotope study.". The American Naturalist 154 (4): 406–416.  
  8. ^ Odum, E. P.; Barrett, G. W. (2005). Fundamentals of ecology.  
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