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Food chain

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Food chain

  1. 1. FOOD CHAIN A food chain is a linear sequence of links in a food web starting from a species that are called producers in the web and ends at a species that is called decomposers species in the web. A food chain also shows how the organisms are related with each other by the food they eat. 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.
  2. 2. Characteristics of a Food Chain In a food chain, a) there is repeated eating in which each group eats the smaller one and is eaten by the larger one. Thus, it involves a nutritive interaction between the biotic components of an ecosystem. b) the plants and animals which depend successively on one another form the limbs of a food chain. c) there is unidirectional flow of energy from sun to producers and then to a series of consumers of various types. Thus, a food chain is always straight and proceeds in a progressing straight line.
  3. 3. d) usually 80 to 90% of potential energy is lost as heat at each transfer on the basis of second law of thermodynamics (transformation of energy involves loss of unavailable energy). e) usually there are 4 or 5 trophic levels. Shorter food chains provide greater available energy and vice - versa. f ) omnivores occupy more than one trophic level and, some organisms occupy different trophic positions in different food chains.
  5. 5.  Grass Grasshopper Frog Snake Grass Grasshopper Cock Vanda Worms Crow Grass Grasshopper Chameleon Owl Grass Grasshopper Rat Snake Eagle
  6. 6. Climbers Worms Frog Snake  Mango Tree Squirrels Snake Eagle Grass Beetle Rat Snake