Ecological Pyramids

Ecological Pyramids

Pyramid of Energy: At each link in the food chain, energy that was originally stored by the autotrophs (producers) is lost along the food chain. The more links in the food chain, the more lost or unusable energy. There is generally a 90 percent loss at each link of the food chain, creating a pyramid-shaped diagram that is wider at the bottom and narrow at the top.
Pyramid of Mass & Numbers: The mass (weight) and numbers of organisms decreases along a food chain (e.g. grass-grasshoppers-frogs-snakes-hawk). It takes many pounds of grass (or numerous grass plants) to support one hawk at the top of a food chain.

Biomass Pyramid Energy Pyramid

On the pyramid on the next page you will be making one side an pyramid by energy, the next side a pyramid by numbers, and the final side a pyramid by biomass. The fourth pyramid is to glue behind the first pyramid. You will leave it blank.

1.  On the base (largest box) of the first pyramid label it a pyramid of energy.

2.  On the base of the second pyramid label it a pyramid of numbers.

3.  On the base of the third pyramid label it a pyramid of mass.

4.  Label each level of all three pyramids with the following terms as you move up the pyramid: producer, primary consumer, secondary consumer, tertiary consumer.

5.  Label each level of all three pyramids with the following terms as you move up the pyramid: 1st trophic level, 2nd trophic level, 3rd tropic level, 4th trophic level.

6.  Label each level of all three pyramids with the following terms as your move up the pyramid: autotroph, heterotroph herbivore, heterotroph carnivore, heterotroph top carnivore.

7.  Draw a picture of what might belong in each level: Use the food chain above (start with the leaves).

8.  Use the following chart to fill in the information for each type of pyramid.

Numbers / Weight per individual (grams) / Total energy (kcal)
Leaves / 10,000 / 10,000 / 1000
Slugs / 2,500 / 5000 / 100
Frogs / 100 / 3000 / 10
Herons / 1 / 2000 / 1

9.  Color your pyramid and be as creative as you want without hiding or erasing any of the information.

10. Put glue on the blank pyramid. Fold your pyramid on the lines radiating from the center and tuck the blank pyramid behind the first pyramid.

10. Answer the following questions using your pyramid:

a.  What are three terms used to describe organisms such as trees?

b.  What are three terms used to describe organisms such as slugs?

c.  What are three terms used to describe organisms such as frogs?

d.  What are three terms sued to describe organisms such as herons?

e.  What are the difference between the three types of pyramids? What do they each show?

f.  How much energy is transferred between each trophic level? (Give as a percent.)