Food ChainFood Chain – a model of how energy is passed – a model of how energy is passed from organism to organism in a communityfrom organism to organism in a community

Energy moves from one organism to the next in a one-way directionEnergy moves from one organism to the next in a one-way direction

ArrowsArrows show the direction of show the direction of energy energy transfertransfer

Because few organisms eat just one kind of food, simple food chains Because few organisms eat just one kind of food, simple food chains are rareare rare

Who’s who in a food chain?Who’s who in a food chain?The The 11stst link link in any food chain is a in any food chain is a producerproducerThe The 22ndnd link link is usually an is usually an herbivoreherbivore – This is the This is the primary consumer – primary consumer – the first the first

consumer in the food chainconsumer in the food chainThe The 33rdrd link link of a food chain is a of a food chain is a carnivorecarnivore or or omnivoreomnivore – This is theThis is the secondary consumer – secondary consumer – the the

second consumer in the chainsecond consumer in the chainThe The 44thth link link is also a is also a carnivorecarnivore or or omnivoreomnivore– This is the This is the tertiary consumer – tertiary consumer – the third the third

consumer in the chainconsumer in the chainWhen organisms die in any ecosystem, When organisms die in any ecosystem, decomposersdecomposers feed on them, in order to break feed on them, in order to break down the remains and down the remains and recyclerecycle nutrients nutrients

Food WebFood Web – – a model that shows a model that shows allall the possible the possible feeding relationships among organisms in a communityfeeding relationships among organisms in a community

More on Food WebsMore on Food Webs

Food webs are a more complete model of Food webs are a more complete model of the way energy moves through a the way energy moves through a communitycommunity

They are They are more accuratemore accurate because they because they show the show the many organismsmany organisms that feed on that feed on more than one level in an ecosystemmore than one level in an ecosystem

Food webs are like a series of Food webs are like a series of overlapping food chainsoverlapping food chains

DecreasingNumber of organisms

Decreasing Amount of energy

Producer:

Primary (1st) Consumer:

Secondary (2nd) Consumer:

The pyramid represents energy. As you can see, more energy is available at the base of the pyramid than at its top.

Facts about Energy Pyramids:Facts about Energy Pyramids:

Energy pyramidEnergy pyramid - - a diagram that shows the amount a diagram that shows the amount of energy available at each feeding level in an of energy available at each feeding level in an ecosystemecosystemFood chains usually have at least 3 links, but rarely Food chains usually have at least 3 links, but rarely more than 5more than 5This limit exists because the amount of available This limit exists because the amount of available energy is reducedenergy is reduced as you move from one level to the as you move from one level to the next in a food chainnext in a food chainOnly about Only about 10%10% of the energy available of the energy available is transferredis transferred to the next levelto the next level90%90% of the energy is of the energy is used by the organismused by the organism (digestion, hunting, breathing, lost as heat)(digestion, hunting, breathing, lost as heat)

Energy PyramidsEnergy Pyramids