Food Chain
A food chain is the passing of energy through animals eating each other. Simple food chain are rare because most animals eat more than just one kind of organism. At the bottom of the food chain is the producers. The organisms that eat the producers are called primary consumers. The organisms that eat the primary consumers are called third level or secondary consumers. The top of the food chain is the tertiary consumers they eat the third level/scondary consumers. The more you go up the food chain the less energy there is.
Energy Pyramid
An energy pyramid is a diagram that shows the energy loss at each level on the food chain. At the bottom you have the producers which has a large population and a lot of energy. The energy decreases by 90% each level and has 10% available of energy. There is less energy at the top because only energy stored in the tissues of an organism can be moved to the next level.