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

An energy pyramid shows the distribution of energy among trophic levels. energy transferred energy lost Energy pyramids compare energy used by producers and other organisms on trophic levels. Between each tier of an energy pyramid, up to 90 percent of the energy is lost into the atmosphere as heat. Only 10 percent of the energy at each tier is transferred from one trophic level to the next.

Other pyramid models illustrate an ecosystem’s biomass and distribution of organisms. Biomass is a measure of the total dry mass of organisms in a given area. tertiary consumers secondary primary producers 75 g/m2 150g/m2 675g/m2 2000g/m2

A pyramid of numbers shows the numbers of individual organisms at each trophic level in an ecosystem. tertiary consumers secondary primary producers 5 5000 500,000 5,000,000 A vast number of producers are required to support even a few top level consumers.

Each level in a food chain contains less energy than the one below it because some energy is Added to the system Lost as heat Consumed by carnivores Incorporated into biomass

The term biomass refers to the total Dry mass of the organisms in a given area Unused material excreted as waste Producer-to-consumer ratio Mass of all living things on Earth

A diagram that shows how available energy is distributed among trophic levels in an ecosystem is called a(n) Food pyramid Pyramid of numbers Food web Energy pyramid

A biomass pyramid is a diagram that compares the Masses of different organisms Number of different organisms Biomass of different trophic levels Distribution of energy in trophic levels

A diagram that shows the numbers of individual organisms at each trophic level in an ecosystem is called a(n) Biomass pyramid Pyramid of numbers Energy pyramid Inverted pyramid