Ecological Pyramids

Ecological Pyramids

• Instead of representing trophic levels in a food web, an ecological pyramid can be used.

Grass (10,000 kcal)

Grasshopper (1,000 kcal)

Frog (100 kcal)

Snake (10 kcal)

Hawk (1 kcal)

1

2

3

4

5

Ecological Pyramids • Does this pyramid represent a food chain

or web?

• How could this pyramid be changed to represent a food web?

Grass (10,000 kcal)

Grasshopper (1,000 kcal)

Frog (100 kcal)

Snake (10 kcal)

Hawk (1 kcal)

1

2

3

4

5

Pyramid of Energy 1. Pyramids of energy show the relative amount of energy available at each trophic level of a food chain or food web. Grass (10,000 kcal)

Grasshopper (1,000 kcal)

Frog (100 kcal)

Snake (10 kcal)

Hawk (1 kcal)

1

2

3

4

5

Ecological Pyramids

• What do the big numbers represent?

• What does the kcal mean?

Grass (10,000 kcal)

Grasshopper (1,000 kcal)

Frog (100 kcal)

Snake (10 kcal)

Hawk (1 kcal)

1

2

3

4

5

Pyramid of Energy • What happens to the energy as you go

up?

• How much energy is available for the next level? (What %)

Grass (10,000 kcal)

Grasshopper (1,000 kcal)

Frog (100 kcal)

Snake (10 kcal)

Hawk (1 kcal)

1

2

3

4

5

Pyramid of Energy 2. The transfer of energy and matter in a food chain is only about 10% efficient because the other 90% is used to perform life processes.

Grass (10,000 kcal)

Grasshopper (1,000 kcal)

Frog (100 kcal)

Snake (10 kcal)

Hawk (1 kcal)

1

2

3

4

5

Pyramid of Energy

3. Where is the most energy located in this type of pyramid?

At the bottom

Grass (10,000 kcal)

Grasshopper (1,000 kcal)

Frog (100 kcal)

Snake (10 kcal)

Hawk (1 kcal)

1

2

3

4

5

Pyramid of Energy 4. Where is the least

amount of energy located?

At the top!

Grass (10,000 kcal)

Grasshopper (1,000 kcal)

Frog (100 kcal)

Snake (10 kcal)

Hawk (1 kcal)

1

2

3

4

5

Ecological Pyramids • How is this pyramid different from the

previous ones?

• What could the multiple pictures of the species at each level represent?

Pyramid of Biomass

A pyramid of biomass illustrates the relative amount of living organic matter available at each trophic level

Biomass-the total amount of living tissue within a given trophic level.

Pyramid of Biomass

• Drying and weighing a sample number of organisms at each level and then calculating the total mass for the species at each level.

3. How do they get a number total for the biomass of a population?

Pyramid of Biomass

Pyramid of Biomass

Pyramid of Numbers

1. A pyramid of numbers shows the relative number of individual organisms at each trophic level.

Pyramid of Numbers 2. What information would this pyramid include if it were a pyramid of numbers?

• It would have the total population at each level.

Pyramid of Numbers

• Determined by counting the organisms of a species in a sample portion at each level and then calculating an average for the total area.

3. How do they get a number total for a population of organisms?

Pyramid of Numbers

Pyramid of Numbers

Pyramids of Aquatic Ecosystems

• Numbers

• Biomass

• Energy

Phytoplankton are microscopic and weigh very little

Pyramids of Temperate Forests

• Numbers

• Biomass

• Energy

Trees are huge but not as numerous as many smaller forest

creatures.