Where the energy goes, and why there is never much left at the top.
Every energy pyramid stacks the same four trophic levels. Producers on the bottom, the top predator at the point. You are going to build one in each of three very different places.
Build all three pyramids, one for each ecosystem. Pick an organism, then click the level where it belongs. The organisms change every time. Watch what does not.
Each level here shows one example organism. A real ecosystem has many different species at every level. The shape shows the order of the levels, and the real energy numbers come in Step 2.
Only about 10% of the energy at one level makes it to the level above. Watch what that does over four levels.
Leave the producers at 10,000 kcal and press Send the energy. Watch the squares. Then drag the slider and send it again. Last, switch to another ecosystem and send it one more time. Completely different organisms. Look hard at the numbers.
Press Send the energy to start.
A kcal is a unit of energy, the same one on a food label. The shape shows the order of the levels, the numbers show the real energy, and one square is 100 kcal.
Same rule, run backward. Start with what the top predator needs and work down to the producers.
Set what the top predator needs, then read the producer level at the bottom. Then turn on the fifth level and see what is left. Switch ecosystems if you like: the organisms change, the arithmetic does not.
The shape shows the order of the levels. The numbers show the real energy.
Eight questions. Your answers are saved if you jump back to another step.