An ecosystem is an environment in which living and nonliving things interact in order to survive. In an ecosystem, living creatures eat nonliving things. This is an ecosystem. Living things get their energy from many things. For example, the grass gets its energy from the sun. Some animals get their energy from other things by eating them. As an example, in the temperate forest, Fox eat deer. If one of the species in the food web is gone, or extinct, many bad things can happen. If one thing is gone, then other things can eat them. If there are too little, then the predator will eat then them quickly, and they won’t have any more to eat. But in every ecosystem, the sun I the ultimate source of energy. The sun powers the food web/chain.