Section 13-6Section 13-6“Pyramid Models”“Pyramid Models”

Write everything Write everything that isthat is underlinedunderlined

13.6 Pyramid Models

KEY CONCEPTKEY CONCEPT: : Pyramids model the distribution of Pyramids model the distribution of energy and matter in an ecosystem.energy and matter in an ecosystem.

13.6 Pyramid Models

energy transferredenergy transferredenergyenergylostlost

I. Energy PyramidsI. Energy Pyramids

1.1.Energy PyramidsEnergy Pyramids compare energy compare energy used by producers and other used by producers and other organisms on trophic levelsorganisms on trophic levels..

2.2. A Trophic A Trophic level is a level is a feeding levelfeeding level

13.6 Pyramid Models

energy transferredenergy transferredenergyenergylostlost

3.3. Between each tierBetween each tier (level) (level) of an energy pyramid, of an energy pyramid, up up to 90 percent of the to 90 percent of the energy is lostenergy is lost into the into the atmosphere atmosphere as heatas heat..

4.4. Only 10 percent of the Only 10 percent of the energy at each tier is energy at each tier is transferredtransferred from one from one trophic level to the next. trophic level to the next.

13.6 Pyramid Models

tertiarytertiaryconsumersconsumers

secondarysecondaryconsumersconsumers

primaryprimaryconsumersconsumers

producers

75 g/m275 g/m2

150g/m2150g/m2

675g/m2675g/m2

2000g/m2producersproducers 2000g/m22000g/m2

II. II. Other Pyramid ModelsOther Pyramid Models1. Other pyramid models illustrate an 1. Other pyramid models illustrate an ecosystem’s biomass and distribution of ecosystem’s biomass and distribution of organismsorganisms..

2.2. Biomass isBiomass is a measure of a measure of the total dry mass the total dry mass of organisms in a given area.of organisms in a given area.

13.6 Pyramid Models

tertiarytertiaryconsumersconsumers

secondarysecondaryconsumersconsumers

primaryprimaryconsumersconsumers

producers

55

50005000

500,000500,000

5,000,0005,000,0005,000,000producersproducers

3.3. A pyramid of numbers shows the numbers of A pyramid of numbers shows the numbers of individual organisms at each trophic levelindividual organisms at each trophic level in an in an ecosystem.ecosystem.

4.4. A large number of producers are required A large number of producers are required to support even a few top level consumersto support even a few top level consumers..

13.6 Pyramid Models

Study GuideStudy Guide

• Do Vocabulary Review 13-6 pg. 238 Do Vocabulary Review 13-6 pg. 238 • Chapter Review pg. 239Chapter Review pg. 239