Food Chain

All energy on the Earth comes from the Sun. A simple activity illustrates how this energy gets from one organism to another within an ecosystem. In this ecosystem, clover grows, is eaten by a rabbit, which in turn is eaten by a hawk. When the hawk dies, it is decomposed by fungus.

Materials:

• 1-meter length of paper
• Metric Ruler
• Scissors

Procedure:
Imagine the energy of the sun as the 1-meter length of paper. The first organism in the food chain, in this case clover, has 10% of the sun’s energy available. On the strip of paper, that would be 10 centimeters.

Measure ten centimeters and cut off the rest of the strip. These 10 centimeters represent the amount of the Sun’s energy that is in the plant.

Now the rabbit comes along to eat the clover. The rabbit only has 10% of the clover’s energy available to it. That would be 1 centimeter.

Measure one centimeter and cut off the rest. That is all that the rabbit gets from the plant.

In turn, the hawk will only have about 10% of the energy from the rabbit, or about 1 millimeter. Measure one millimeter and cut off the rest.

Finally, the fungi get 10% of what is left, about .1 millimeters. Measure as best you can .1 millimeter and cut off the rest.

Along the way, from one level to the next, all of the rest of the energy is lost to the atmosphere as heat.

Extension:
Teachers/Parents: To incorporate Mathematics skills, have children try to figure out the amount of the strip that would be cut off if 10% is available. Vary the percentages for hypothetical situations and have children calculate how much to cut.

Students: Use a different length strip of paper and calculate the length of paper that would represent the energy available to each organism.

10 - 15 minutes

After successfully completing the activity, be able to state that all energy comes from the Sun and briefly explain how that energy gets transferred from one organism to another within an ecosystem.