Living things can be classified on the basis of how they obtain energy. Some use the energy in sunlight or chemical compounds directly to make food. Some get energy indirectly by consuming other organisms, either living or dead.     Producers are living things that produce food for themselves and other organisms. They use energy and simple inorganic molecules to make organic compounds. Producers are vital to all ecosystems because all organisms need organic compounds for energy. Producers are also called autotrophs. There are two basic types of autotrophs.     Photoautotrophs use energy in... Show more

Living things can be classified on the basis of how they obtain energy. Some use the energy in sunlight or chemical compounds directly to make food. Some get energy indirectly by consuming other organisms, either living or dead.    
Producers are living things that produce food for themselves and other organisms. They use energy and simple inorganic molecules to make organic compounds. Producers are vital to all ecosystems because all organisms need organic compounds for energy. Producers are also called autotrophs. There are two basic types of autotrophs.    
Photoautotrophs use energy in sunlight to make organic compounds by photosynthesis. Chemoautotrophs use energy in chemical compounds to make organic compounds by chemosynthesis.    
Consumers are organisms that depend on other living things for food. They take in organic compounds by eating or absorbing other living things. Consumers are also called heterotrophs. There are several different types of heterotrophs depending on exactly what they consume. Herbivores consume producers such as plants or algae, carnivores consume animals, and omnivores consume both plants and animals.    
Some heterotrophs are decomposers that break down the wastes of other organisms or the remains of dead organisms.    
They release simple inorganic molecules back into the environment so producers can then use them to make new organic compounds. For this reason, decomposers are essential to every ecosystem.

Decomposers are classified by the type of organic matter they break down. Scavengers consume the soft tissues of dead animals. Detritivores consume dead leaves, animal feces, and other organic debris that collects on the ground or at the bottom of a body of water. Saprotrophs feed on any remaining organic matter that is left after other decomposers do their work.

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