This activity is easy to set up. All you need are scissors, paper and the included diagram to cut up. Students cut out the organisms and then place them on a pyramid they make out of paper in the proper order. They use the numbers on the organisms to figure out the number of organisms at each level and at the same time, the number of joules of energy at each level. I have predetermined that there will be a 10% reduction at each level. It's a simple activity, but it explains the pyramids and food chain pretty well.