Food chains, also called , food networks and/or trophic networks, describe the feeding relationships between species within an ecosystem. An ecosystem is a natural unit consisting of all plants animals and micro-organisms( Biotic factors in an area functioning together with all of the non-living physical ( Organisms are connected to the organisms they consume by arrows representing the direction of biomass transfer. Biomass refers to living and recently dead Biological material that can be used as fuel or for industrial production It also shows you how the energy from the producer is given to the consumer. In Physics and other Sciences energy (from the Greek grc ἐνέργεια - Energeia, "activity operation" from grc ἐνεργός Consumers refers to individuals or households that use goods and services generated within the economy. Typically a food chain or food web refers to a graph where only connections are recorded, and a food network or ecosystem network refers to a network where the connections are given weights representing the quantity of nutrients or energy being transfered.

ś==Organisms represented in food chains== Primary producers, commonly called the autotrophs, are species capable of producing complex organic substances (essentially "food") from an energy source and inorganic materials. An autotroph (from the Greek autos = self and trophe = nutrition is an Organism that produces complex Organic compounds from simple These organisms are typically photosynthetic plants, bacteria or algae, but in rare cases, like those organisms forming the base of deep-sea vent food webs, can be chemotrophic. Photosynthesis is a Metabolic pathway that converts Light Energy into Chemical energy. The Bacteria ( singular: bacterium) are a large group of unicellular Microorganisms Typically a few Micrometres in length bacteria have Algae ( sing. alga are a large and diverse group of simple typically Autotrophic organisms ranging from Unicellular to Multicellular forms Chemotrophs are organisms that obtain Energy by the Oxidation of Electron donating Molecules in their environments Organisms that get their energy by consuming organic substances are called heterotrophs. A heterotrophs, or chemoorganotrophy ( Greek heterone = (another and trophe = nutrition is an Organism that requires Heterotrophs include herbivores, which obtain their energy by consuming live plants; carnivores, which obtain energy from eating live animals; as well as detritivores, scavengers and decomposers, which all consume dead biomass. A heterotrophs, or chemoorganotrophy ( Greek heterone = (another and trophe = nutrition is an Organism that requires Herbivory is a form of Predation in which an Organism, known as a herbivore, consumes principally Autotrophs ref name=Campbell>Campbell Plants are living Organisms belonging to the kingdom Plantae. A carnivore (ˈkɑrnɪvɔər meaning 'meat eater' ( Latin carne meaning 'flesh' and vorare meaning 'to devour' is any animal with a diet consisting Detritivores, also known as detritus feeders or saprophages, are Heterotrophs that obtain Nutrients by consuming Detritus (decomposing Scavenging, or necrophagy, is a Carnivorous Feeding behaviour in which a predator consumes Corpses or Carrion that were killed Decomposers (or Saprotrophs) are organisms that consume dead organisms and in doing so carry out the natural process of Decomposition. Energy enters the food chain from the sun. Some energy and/or biomass is lost at each stage of the food chain as; feces (solid waste), movement energy and heat energy (especially by birds and mammals). Therefore, only a small amount of energy and biomass is incorporated into consumer's body and transferred to the next feeding level, thus showing a Pyramid of Biomass.

Example of a food chain in a Swedish lake

A food chain is the flow of energy from one organism to the next and to the next and to the next. Organisms in a food chain are grouped into trophic levels — from the Greek word for nourishment, trophikos — based on how many links they are removed from the primary producers. In Ecology, trophic dynamics is the system of trophic levels ( Greek trophē, food which describe the position that an organism occupies See also Primary production (economics Primary production is the production of Organic compounds from atmospheric or aquatic Carbon dioxide, Trophic levels may consist of either a single species or a group of species that are presumed to share both predators and prey. In Ecology, trophic dynamics is the system of trophic levels ( Greek trophē, food which describe the position that an organism occupies They usually start with a primary producer and end with a carnivore. The diagram at right is a food chain from a Swedish lake. It can be described as follows: osprey feed on northern pike, that feed on perch, that eat bleak, that feed on freshwater shrimp. The Osprey (Pandion haliaetus, also called Sea Hawk, is a diurnal, fish-eating Bird of prey. The northern pike (known as the pike in Britain Esox lucius, is a Species of carnivorous Fish of the genus Esox (the pikes Perca is the genus of fish referred to as perch or sometimes yellow perch, a group of freshwater Fish belonging to the family Percidae True shrimp are swimming decapod Crustaceans classified in the Infraorder Caridea, found widely around the world in both fresh Although they are not shown in this diagram, the base of this food chain is likely phytoplankton. Phytoplankton are the Autotrophic component of the Plankton community Phytoplankton are autotrophs, and are the base of the food chain by virtue of their ability to photosynthesize. Phytoplankton are the Autotrophic component of the Plankton community An autotroph (from the Greek autos = self and trophe = nutrition is an Organism that produces complex Organic compounds from simple Photosynthesis is a Metabolic pathway that converts Light Energy into Chemical energy. Phytoplankton, as well as attached algae form the base of most freshwater food chains. Algae ( sing. alga are a large and diverse group of simple typically Autotrophic organisms ranging from Unicellular to Multicellular forms It is often the case that biomass of each trophic level decreases from the base of the chain to the top. Biomass refers to living and recently dead Biological material that can be used as fuel or for industrial production In Ecology, trophic dynamics is the system of trophic levels ( Greek trophē, food which describe the position that an organism occupies This is because energy is lost to the environment with each transfer. On average, only 10% of the organism's energy is passed on to its predator. The other 90% is used for the organisms life processes or it is lost as heat to the environment. Graphic representations of the biomass or productivity at each trophic level are called trophic pyramids. An interesting face(or Trophic pyramid) is a graphical representation designed to show the Biomass or productivity at each Trophic level in a given In this food chain for example, the biomass of osprey is smaller than the biomass of pike, which is smaller than the biomass of perch. Some producers, especially phytoplankton, are so productive and have such a high turnover rate that they can actually support a larger biomass of grazers. This is called an inverted pyramid, and can occur when consumers live longer and grow more slowly than the organisms they consume. In this food chain, the productivity of phytoplankton is much greater than that of the zooplankton consuming them. The biomass of the phytoplankton, however, may actually be less than that of the copepods. Directly linked to this are pyramids of numbers, which show that as the chain is traveled along, the number of consumers at each level drops very significantly, so that a single top consumer (e. A pyramid of numbers shows graphically the population of each level in a Food chain. g. a Polar Bear) will be supported by literally millions of separate producers (e. The polar bear ( Ursus maritimus) is a Bear native to the Arctic Ocean and its surrounding seas g. Phytoplankton). Phytoplankton are the Autotrophic component of the Plankton community Food chains are overly simplistic as representatives of what typically happens in nature. The food chain shows only one pathway of energy and material transfer. Most consumers feed on multiple species and are, in turn, fed upon by multiple other species. The relations of detritivores and parasites are seldom adequately characterized in such chains as well. The food chain has a producer, consumer, herbivore, carnivore, omnivore, decomposer. Arrows in a food web represent an organism getting eaten by another organism.

Food web

A food web extends the food chain concept from a simple linear pathway to a complex network of interactions. The earliest food webs were published by Victor Summerhayes and Charles Elton in 1923 and Hardy in 1924. Charles Sutherland Elton ( 29 March 1900 &ndash 1 May 1991) was an English zoologist and animal ecologist Summerhayes and Elton's (right) depicted the interactions of plants, animals and bacteria on Bear Island, Norway,^[1] while Hardy's food web showed the interactions of herring and plankton in the North Sea. Charles Sutherland Elton ( 29 March 1900 &ndash 1 May 1991) was an English zoologist and animal ecologist Plants are living Organisms belonging to the kingdom Plantae. The Bacteria ( singular: bacterium) are a large group of unicellular Microorganisms Typically a few Micrometres in length bacteria have Bjørnøya, Bear Island in Norwegian is a common name for Norwegian islands Bear Island (Norway in the Svalbard Archipelago, in Norway ( Norwegian: Norge ( Bokmål) or Noreg ( Nynorsk) officially the Kingdom of Norway, is a Constitutional Herring are small Oily fish of the genus Clupea found in the shallow temperate waters of the North Atlantic, the Baltic Sea, the North Plankton consist of any drifting Organisms ( Animals Plants Archaea, or Bacteria) that inhabit the Pelagic zone of The North Sea is a marginal, Epeiric sea of the Atlantic Ocean on the European Continental shelf.

The direct steps as shown in the food chain example above seldom reflect reality. This web makes it possible to show much bigger animals (like a seal) eating very small organisms (like plankton). Food sources of most species in an ecosystem are much more diverse, resulting in a complex web of relationships as shown in the figure on the right. In this figure, the grouping of Algae → Protozoa → Oligochaeta → Northern Eider → Arctic Fox is a chain; the whole complex network is a food web. Algae ( sing. alga are a large and diverse group of simple typically Autotrophic organisms ranging from Unicellular to Multicellular forms Protozoa (in Greek πρῶτον proton "first" and ζῷα zoia "animals" are unicellular Eukaryotes (singular For the plant Genus from the sunflower family ( Asteraceae) see Oligochaeta (plant. For the river see Eider River. For other uses see Eider (disambiguation. The Arctic Fox ( Vulpes lagopus) also known as the White Fox or Snow Fox, is a small Fox native to cold Arctic regions of the

References

• "Food chain" A Dictionary of Zoology. Ed. Michael Allaby. Oxford University Press, 1999. Oxford Reference Online. Oxford University Press. University of Utah. 22 November 2007 [http://www.oxfordreference.com/views/ENTRY.html?subview=Main&entry=t8.e3348