8/2/2019 An Ecological Pyramid

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An ecological pyramid (also trophic pyramid orenergy pyramid) is a graphical representationdesigned to show thebiomassorbiomass productivityat eachtrophic levelin a givenecosystem.

Biomassis the amount of living or organic matter

present in an organism. Biomass pyramidsshow howmuch biomass is present in the organisms at eachtrophic level, while productivity pyramidsshow theproduction or turnover in biomass.

Ecological pyramids begin withproducerson thebottom (such as plants) and proceed through thevarious trophic levels (such as herbivores that eatplants, then carnivores that eat herbivores, thencarnivores that eat those carnivores, and so on). Thehighest level is thetopof thefood chain.

Contents

1 Pyramid of biomass 2 Pyramid of productivity 3 Pyramid of numbers 4 See also 5 References 6 External links

Pyramid of biomass

An ecological pyramid of biomassshows the

relationship between biomass and trophic level byquantifying the amount of biomass present at eachtrophic level of anecological communityat aparticular moment in time. Typical units for a biomasspyramid could be grams per meter

2, or calories per

meter2.

The pyramid of biomass may be 'inverted'. Forexample, in a pond ecosystem, thestanding cropofphytoplankton, the majorproducers, at any givenpoint will be lower than the mass of theheterotrophs,such as fish and insects. This is explained as the

phytoplanktonreproducevery quickly, but have muchshorter individual lives.

One problem with biomass pyramids is that they canmake a trophic level look like it contains moreenergythan it actually does. For example, allbirdshave

beaksandskeletons, which despite taking upmassare not eaten by the next trophic level. In a pyramid ofbiomassthe skeletons and beaks would still bequantified even though they do not contribute to theoverall flow of energy when ripping and tearing intothe next trophic level.

Pyramid of productivity

An ecological pyramid of productivityis often moreuseful, showing the production or turnover of biomassat each trophic level. Instead of showing a singlesnapshot in time,productivitypyramids show the flowofenergythrough thefood chain. Typical units would

be grams per meter

2

per year or calories per meter

2

per year. As with the others, this graph begins withproducers at the bottom and places higher trophiclevels on top.

When an ecosystem is healthy, this graph produces astandard ecological pyramid. This is because in orderfor the ecosystem to sustain itself, there must bemore energy at lower trophic levels than there is athigher trophic levels. This allows for organisms on thelower levels to not only maintain a stable population,but to also transfer energy up the pyramid. Theexception to this generalization is when portions of afood webare supported by inputs of resources fromoutside of the localcommunity. In small, forested

streams, for example gone up greater than could besupported by the localprimary production.

Read more:http://www.answers.com/topic/ecological-pyramid#ixzz1TdpWVyyi

Pyramid of numbers

An ecological pyramid of numbersshows graphicallythe population of each level in afood chain.

The diagram to the right shows a (nonfictional)

example of a five level pyramid of numbers: 10,000fresh watershrimpssupport 1,000bleak, which in turnsupport 100perchesfollowed by 10northern pikesand finally oneosprey.

Read more:http://www.answers.com/topic/ecological-pyramid#ixzz1TdpdeujR

Introduction

We are always considerate of the energy (as trophicstructures or layers) in an ecosystem for many

reasons. It is the availability of energy that determinesthe length and complexity of any ecosystem.Ecologists are always eager to both determine andexplain the energy flow in a system, and food chains,webs and pyramids are one of many ways to describethe trophic structure in an ecosystem.

Food Chains

A food chain is the most simple of the three commontrophic descriptors, and is probably a concept quitefamiliar to you already. With primary and secondaryproductivity explained, we need to look at how energy

http://www.answers.com/topic/biomass-ecologyhttp://www.answers.com/topic/biomass-ecologyhttp://www.answers.com/topic/biomass-ecologyhttp://www.answers.com/topic/primary-productionhttp://www.answers.com/topic/primary-productionhttp://www.answers.com/topic/primary-productionhttp://www.answers.com/topic/trophic-level-1http://www.answers.com/topic/trophic-level-1http://www.answers.com/topic/trophic-level-1http://www.answers.com/topic/ecosystems-1http://www.answers.com/topic/ecosystems-1http://www.answers.com/topic/ecosystems-1http://www.answers.com/topic/autotroph-2http://www.answers.com/topic/autotroph-2http://www.answers.com/topic/autotroph-2http://www.answers.com/topic/apex-predatorhttp://www.answers.com/topic/apex-predatorhttp://www.answers.com/topic/apex-predatorhttp://www.answers.com/topic/food-chain-2http://www.answers.com/topic/food-chain-2http://www.answers.com/topic/food-chain-2http://www.answers.com/topic/ecological-pyramid#Pyramid_of_biomasshttp://www.answers.com/topic/ecological-pyramid#Pyramid_of_biomasshttp://www.answers.com/topic/ecological-pyramid#Pyramid_of_productivityhttp://www.answers.com/topic/ecological-pyramid#Pyramid_of_productivityhttp://www.answers.com/topic/ecological-pyramid#Pyramid_of_numbershttp://www.answers.com/topic/ecological-pyramid#Pyramid_of_numbershttp://www.answers.com/topic/ecological-pyramid#See_alsohttp://www.answers.com/topic/ecological-pyramid#See_alsohttp://www.answers.com/topic/ecological-pyramid#Referenceshttp://www.answers.com/topic/ecological-pyramid#Referenceshttp://www.answers.com/topic/ecological-pyramid#External_linkshttp://www.answers.com/topic/ecological-pyramid#External_linkshttp://www.answers.com/topic/biocoenosis-1http://www.answers.com/topic/biocoenosis-1http://www.answers.com/topic/biocoenosis-1http://www.answers.com/topic/standing-crop-1http://www.answers.com/topic/standing-crop-1http://www.answers.com/topic/standing-crop-1http://www.answers.com/topic/phytoplanktonhttp://www.answers.com/topic/phytoplanktonhttp://www.answers.com/topic/autotroph-2http://www.answers.com/topic/autotroph-2http://www.answers.com/topic/autotroph-2http://www.answers.com/topic/heterotrophhttp://www.answers.com/topic/heterotrophhttp://www.answers.com/topic/heterotrophhttp://www.answers.com/topic/reproduction-4http://www.answers.com/topic/reproduction-4http://www.answers.com/topic/reproduction-4http://www.answers.com/topic/energyhttp://www.answers.com/topic/energyhttp://www.answers.com/topic/energyhttp://www.answers.com/topic/birdhttp://www.answers.com/topic/birdhttp://www.answers.com/topic/birdhttp://www.answers.com/topic/beakhttp://www.answers.com/topic/beakhttp://www.answers.com/topic/skeleton-1http://www.answers.com/topic/skeleton-1http://www.answers.com/topic/skeleton-1http://www.answers.com/topic/masshttp://www.answers.com/topic/masshttp://www.answers.com/topic/masshttp://www.answers.com/topic/productivityhttp://www.answers.com/topic/productivityhttp://www.answers.com/topic/productivityhttp://www.answers.com/topic/energyhttp://www.answers.com/topic/energyhttp://www.answers.com/topic/energyhttp://www.answers.com/topic/food-chain-2http://www.answers.com/topic/food-chain-2http://www.answers.com/topic/food-chain-2http://www.answers.com/topic/food-chainhttp://www.answers.com/topic/food-chainhttp://www.answers.com/topic/biocoenosis-1http://www.answers.com/topic/biocoenosis-1http://www.answers.com/topic/biocoenosis-1http://www.answers.com/topic/streamhttp://www.answers.com/topic/streamhttp://www.answers.com/topic/primary-productionhttp://www.answers.com/topic/primary-productionhttp://www.answers.com/topic/primary-productionhttp://www.answers.com/topic/ecological-pyramid#ixzz1TdpWVyyihttp://www.answers.com/topic/ecological-pyramid#ixzz1TdpWVyyihttp://www.answers.com/topic/ecological-pyramid#ixzz1TdpWVyyihttp://www.answers.com/topic/ecological-pyramid#ixzz1TdpWVyyihttp://www.answers.com/topic/food-chain-2http://www.answers.com/topic/food-chain-2http://www.answers.com/topic/food-chain-2http://www.answers.com/topic/shrimphttp://www.answers.com/topic/shrimphttp://www.answers.com/topic/shrimphttp://www.answers.com/topic/common-bleakhttp://www.answers.com/topic/common-bleakhttp://www.answers.com/topic/common-bleakhttp://www.answers.com/topic/perchhttp://www.answers.com/topic/perchhttp://www.answers.com/topic/perchhttp://www.answers.com/topic/northern-pikehttp://www.answers.com/topic/northern-pikehttp://www.answers.com/topic/northern-pikehttp://www.answers.com/topic/ospreyhttp://www.answers.com/topic/ospreyhttp://www.answers.com/topic/ospreyhttp://www.answers.com/topic/ecological-pyramid#ixzz1TdpdeujRhttp://www.answers.com/topic/ecological-pyramid#ixzz1TdpdeujRhttp://www.answers.com/topic/ecological-pyramid#ixzz1TdpdeujRhttp://www.answers.com/topic/ecological-pyramid#ixzz1TdpdeujRhttp://en.wikipedia.org/wiki/File:Pyramid_of_numbers.pnghttp://en.wikipedia.org/wiki/File:Pyramid_of_numbers.pnghttp://en.wikipedia.org/wiki/File:Pyramid_of_numbers.pnghttp://en.wikipedia.org/wiki/File:Pyramid_of_numbers.pnghttp://www.answers.com/topic/ecological-pyramid#ixzz1TdpdeujRhttp://www.answers.com/topic/ecological-pyramid#ixzz1TdpdeujRhttp://www.answers.com/topic/ospreyhttp://www.answers.com/topic/northern-pikehttp://www.answers.com/topic/perchhttp://www.answers.com/topic/common-bleakhttp://www.answers.com/topic/shrimphttp://www.answers.com/topic/food-chain-2http://www.answers.com/topic/ecological-pyramid#ixzz1TdpWVyyihttp://www.answers.com/topic/ecological-pyramid#ixzz1TdpWVyyihttp://www.answers.com/topic/primary-productionhttp://www.answers.com/topic/streamhttp://www.answers.com/topic/biocoenosis-1http://www.answers.com/topic/food-chainhttp://www.answers.com/topic/food-chain-2http://www.answers.com/topic/energyhttp://www.answers.com/topic/productivityhttp://www.answers.com/topic/masshttp://www.answers.com/topic/skeleton-1http://www.answers.com/topic/beakhttp://www.answers.com/topic/birdhttp://www.answers.com/topic/energyhttp://www.answers.com/topic/reproduction-4http://www.answers.com/topic/heterotrophhttp://www.answers.com/topic/autotroph-2http://www.answers.com/topic/phytoplanktonhttp://www.answers.com/topic/standing-crop-1http://www.answers.com/topic/biocoenosis-1http://www.answers.com/topic/ecological-pyramid#External_linkshttp://www.answers.com/topic/ecological-pyramid#Referenceshttp://www.answers.com/topic/ecological-pyramid#See_alsohttp://www.answers.com/topic/ecological-pyramid#Pyramid_of_numbershttp://www.answers.com/topic/ecological-pyramid#Pyramid_of_productivityhttp://www.answers.com/topic/ecological-pyramid#Pyramid_of_biomasshttp://www.answers.com/topic/food-chain-2http://www.answers.com/topic/apex-predatorhttp://www.answers.com/topic/autotroph-2http://www.answers.com/topic/ecosystems-1http://www.answers.com/topic/trophic-level-1http://www.answers.com/topic/primary-productionhttp://www.answers.com/topic/biomass-ecology

8/2/2019 An Ecological Pyramid

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