consumers
Heterotrophs cannot make their own food, so they must eat or absorb it. For this reason, heterotrophs are also known as consumers . Consumers include all animals and fungi and many protists and bacteria. They consume either autotrophs or other heterotrophs. Heterotrophs show great diversity and may appear far more fascinating than producers. But heterotrophs are limited by their utter dependence on those autotrophs which originally made the food. If plants, algae, and autotrophic bacteria vanished from Earth, animals, fungi, and other heterotrophs would soon disappear as well. All life requires a constant input of energy. Only autotrophs can transform that ultimate, solar source into the chemical energy in food which powers life, as shown in Figure below .