A: The energy in most ecosystems flows through the food chain. In terrestrial ecosystems and most marine ecosystems, the energy flow starts in green plants that harvest some of the sun’s energy. The plants are then consumed by animals, bacteria and other creatures, which are themselves eaten by other creatures.
All living things need energy. They need it to power the processes of life. For example, it takes energy to grow. It also takes energy to produce offspring. In fact, it takes energy just to stay alive. Remember that energy can’t be created or destroyed. It can only change form. Energy changes form as it moves through ecosystems.
