Why do plants create enough energy for the entire ecosystem?

Question

In my environmental class, we were recently learning about the $10\\%$ law that basically says only $10\\%$ of the energy goes from one trophic level to the next. This got me thinking about *why* energy flows from one level to the next. Specifically, why do plants create enough energy for the entire ecosystem? Wouldn't they do fine without us, and wouldn't that save them the work of creating all that excess energy?

Answer 1

In order to understand this concept, do not look at is as plants creating excess energy. Look at this as plants creating enough energy for themselves, storing some of that energy for later use (such as night time or a rainy day when the sun is blocked out), but never having a chance to use it because some plant eating herbivore came by and ate the plant. Plants dont want to be eaten, they just are, and the energy they didnt have a chance to use is then transferred up.