LO: SWBAT define ecological pyramid and explain its relationship to energy in an ecosystem

DN: Where does all of the energy in an ecosystem come from? Explain.

HW: Article #2 due tomorrow

Ecological Pyramids

A diagram that shows the relative amounts of energy in different trophic

levels in an ecosystem.

Which trophic level is the largest?

Producers

Why?

Energy Pyramid

Producers

1’ Consumers

2’ Consumers

3’ Consumers

En

ergy

Flo

w

What does an ecological pyramid show?

1. Energy

2. Biomass

3. Number of organisms in a food web

Ecological Pyramids show that the energy, biomass, and numbers at any trophic level are less than those of the

trophic level below it.

Pyramid of Numbers

Biomass Pyramid

Energy Pyramid

Section 3-2 Ecological pyramids

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Sun’s Energy in an Ecosystem

• Some of the energy is used by each organism and some of it is lost as heat energy to the environment

Energy Pyramid

• Shows the relative amount of energy available at each trophic level.

• Organisms use about 10 percent of this energy for life processes.

• The rest is lost as heat.

Why is there so little energy at the top of the pyramid?

• Most of the energy from the sun has been used or lost by organism in the lower levels

• Only about 10% of the energy available at each level is transferred to the NEXT level.

100%10%

1%

Biomass Pyramid

• Represents the amount of living organic matter at each trophic level.

• Typically, the greatest biomass is at the base of the pyramid.

Pyramid of NumbersShows the relative number of individual

organisms at each trophic level.

1. What is biomass?

2. Why isn’t all of the energy that enters organisms available to the next trophic level?

3. What three things are ecological pyramids used to represent?

4. From where is the energy in most ecosystems derived?

5. How does the energy, biomass, or population at each trophic level compare to that of the level below it?

1. Biomass is the total amount of organic matter present in a trophic level.

2. Much energy is lost when organisms use it to generate heat and power movements.

3. An ecological pyramid is used to show energy, biomass, or the number of organisms in a food web.

4. Energy in most ecosystems comes from the sun.5. Pyramids of energy, biomass, and numbers

(population) show that the energy, biomass, and numbers at any trophic level are less than those of the trophic level below it.