Food chains
Food chains are simple lists of organisms in an ecosystem, linked by arrows.
In a food chain, what do the arrows represent?
- "is eaten by"
- flow of energy
- flow of organic materials
Food webs
Food webs include several food chains, fanning outwards and upwards.
Their arrangement shows
- alternative flows of energy and organic materials
- that organisms can operate at different trophic levels (e.g. sometimes primary, sometimes secondary or tertiary consumers)
- which organisms are competing with others for the same food