Taxonomy of A Food Web
Food webs are the road-maps through Darwin's famous 'entangled bank' and have a long history in ecology. Like maps of unfamiliar ground, food webs appear bewilderingly complex. They were often published to make just that point. Yet recent studies have shown that food webs from a wide range of terrestrial, freshwater, and marine communities share a remarkable list of patterns.
Links in food webs map the feeding connections (who eats whom) in an ecological community. Food cycle is the antiquated term that is synonymous with food web. Ecologists can broadly lump all life forms into one of two trophic layers, the autotrophs and the heterotrophs. Autotrophs produce more biomass energy, either chemically without the suns energy or by capturing the suns energy in photosynthesis, than they use during metabolic respiration. Heterotrophs consume rather than produce biomass energy as they metabolize, grow, and add to levels of secondary production. A food web depicts a collection of polyphagous heterotrophic consumers that network and cycle the flow of energy and nutrients from a productive base of self-feeding autotrophs.
The base or basal species in a food web are those species without prey and can include autotrophs or saprophytic detritivores (i.e., the community of decomposers in soil, biofilms, and periphyton). Feeding connections in the web are called trophic links. The number of trophic links per consumer is a measure of food web connectance. Food chains are nested within the trophic links of food webs. Food chains are linear (noncyclic) feeding pathways that trace monophagous consumers from a base species up to the top consumer, which is usually a larger predatory carnivore.
Linkages connnect to nodes in a food web, which are aggregates of biological taxa called trophic species. Trophic species are functional groups that have the same predators and prey in a food web. Common examples of an aggregated node in a food web might include parasites, microbes, decomposers, saprotrophs, consumers, or predators, each containing many species in a web that can otherwise be connected to other trophic species.
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Famous quotes containing the words food and/or web:
“One farmer says to me, “You cannot live on vegetable food solely, for it furnishes nothing to make bones with;” and so he religiously devotes a part of his day to supplying his system with the raw material of bones; walking all the while he talks behind his oxen, which, with vegetable-made bones, jerk him and his lumbering plow along in spite of every obstacle.”
—Henry David Thoreau (1817–1862)
“Being so wrong about her makes me wonder now how often I am utterly wrong about myself. And how wrong she might have been about her mother, how wrong he might have been about his father, how much of family life is a vast web of misunderstandings, a tinted and touched-up family portrait, an accurate representation of fact that leaves out only the essential truth.”
—Anna Quindlen (b. 1952)