<P> A food web ( or food cycle ) is a natural interconnection of food chains and a graphical representation ( usually an image ) of what - eats - what in an ecological community . Another name for food web is consumer - resource system . Ecologists can broadly lump all life forms into one of two categories called trophic levels : 1 ) the autotrophs , and 2 ) the heterotrophs . To maintain their bodies , grow , develop , and to reproduce , autotrophs produce organic matter from inorganic substances , including both minerals and gases such as carbon dioxide . These chemical reactions require energy , which mainly comes from the Sun and largely by photosynthesis , although a very small amount comes from hydrothermal vents and hot springs . A gradient exists between trophic levels running from complete autotrophs that obtain their sole source of carbon from the atmosphere , to mixotrophs ( such as carnivorous plants ) that are autotrophic organisms that partially obtain organic matter from sources other than the atmosphere , and complete heterotrophs that must feed to obtain organic matter . The linkages in a food web illustrate the feeding pathways , such as where heterotrophs obtain organic matter by feeding on autotrophs and other heterotrophs . The food web is a simplified illustration of the various methods of feeding that links an ecosystem into a unified system of exchange . There are different kinds of feeding relations that can be roughly divided into herbivory , carnivory , scavenging and parasitism . Some of the organic matter eaten by heterotrophs , such as sugars , provides energy . Autotrophs and heterotrophs come in all sizes , from microscopic to many tonnes - from cyanobacteria to giant redwoods , and from viruses and bdellovibrio to blue whales . </P>
<P> A food web ( or food cycle ) is a natural interconnection of food chains and a graphical representation ( usually an image ) of what - eats - what in an ecological community . Another name for food web is consumer - resource system . Ecologists can broadly lump all life forms into one of two categories called trophic levels : 1 ) the autotrophs , and 2 ) the heterotrophs . To maintain their bodies , grow , develop , and to reproduce , autotrophs produce organic matter from inorganic substances , including both minerals and gases such as carbon dioxide . These chemical reactions require energy , which mainly comes from the Sun and largely by photosynthesis , although a very small amount comes from hydrothermal vents and hot springs . A gradient exists between trophic levels running from complete autotrophs that obtain their sole source of carbon from the atmosphere , to mixotrophs ( such as carnivorous plants ) that are autotrophic organisms that partially obtain organic matter from sources other than the atmosphere , and complete heterotrophs that must feed to obtain organic matter . The linkages in a food web illustrate the feeding pathways , such as where heterotrophs obtain organic matter by feeding on autotrophs and other heterotrophs . The food web is a simplified illustration of the various methods of feeding that links an ecosystem into a unified system of exchange . There are different kinds of feeding relations that can be roughly divided into herbivory , carnivory , scavenging and parasitism . Some of the organic matter eaten by heterotrophs , such as sugars , provides energy . Autotrophs and heterotrophs come in all sizes , from microscopic to many tonnes - from cyanobacteria to giant redwoods , and from viruses and bdellovibrio to blue whales . </P>
what is meant by food chain and food web
what is meant by food chain and food web
a graphical representation ( usually an image ) of what - eats - what in an ecological community
a graphical representation ( usually an image ) of what - eats - what in an ecological community