This document discusses food chains and food webs within an ecosystem. It defines producers as organisms that make their own food, primarily plants. Consumers eat other organisms for energy and can be herbivores, carnivores, or omnivores. Decomposers like bacteria and fungi break down dead plants and animals, returning nutrients to the soil. A food chain shows a single path of energy transfer from producer to consumer, while a food web shows interconnected food chains. An energy pyramid illustrates how little energy remains at higher trophic levels.