The food chain of a producer is the sun, the primary consumer, the secondary consumer and the decomposer. The producer uses the sun and nutrients in the soil to make food, and animals that consume it eventually die and fertilize the soil.
The first step in the food chain of a producer, such as a plant, is using the soil and sun to make its own food. Soon, a primary consumer, usually an herbivore or insect such as a bison or grasshopper, eats the producer. These primary consumers are then eaten by secondary consumers, such as a spider in the case of the grasshopper. Sometimes the food chain consists of long lines of consumers. For instance, a shrew feeds on a spider before a weasel eats the shrew, and a red-tailed hawk captures the weasel before a great-horned owl preys on the hawk. These animals that are higher up on the food chain are tertiary consumers.
These consumers eventually die for various reasons, and their bodies are broken down by decomposers, such as bacteria and fungi. The nutrients return to the soil, and the plants absorb those nutrients when making food. In some cases, plants die before another organism consumes them, and they decompose right away rather than passing their energy up through the food chain.