Food chains and food webs are both ways to model the flow of energy in an ecosystem. Energy pyramids show available energy in each trophic level. Producers are at the bottom of an energy pyramid since the "block" that represents available energy is very large. Not all of the energy flows from the first tropic level to the next one. The energy that does pass from the first to second trophic level is represented by a smaller block. The pattern continues with the top of the pyramid containing the highest consumer possessing the least amount of energy.
Think about this scenario and then complete the activity that follows: You are an ecologist studying organisms in a pond ecosystem. You take a water sample from the pond. Then you observe the following activity: Fish jump out of the water trying to catch mosquitoes above the pond, and an otter swims away with a fish in its mouth. Later in the lab, you see green algae present in the water sample.
Think about the trophic levels in this ecosystem. How could you use your observations both at the pond and in the lab to create an energy pyramid?
| Your Responses | Sample Answers |
|---|---|
| There are four organisms observed: the green algae, the mosquitoes, the fish, and the otter. An energy pyramid would have primary producers as the first trophic level on the bottom of the pyramid, followed by the mosquitoes, and then the fish as the third trophic level. The otter would be at the top of the pyramid, at the highest thropic level. |
