The transfer of energy from organism to organism forms a series called a food chain. All the possible feeding relationships that exist in a biome make up its food web. The food web consists of producers, consumers and decomposers. An analysis of the food web shows how energy is transferred within a biome.
Green plants are the primary producers. They produce organic materials from inorganic chemicals and outside sources of energy, primarily the Sun. Plants turn energy into plant matter, such as seeds, needles and leaves.
Animals are consumers. Plant-eating animals, such as beetles, gazelles and rabbits, are the primary consumers. Secondary consumers eat the plant-eaters. Tertiary consumers are meat-eating predators, like mongooses, owls and coyotes. They consume both primary and secondary consumers. Humans also fall into this category. Some tertiary consumers, like humans and bears, are omnivores, which means they eat both plants and animals.
Decomposers eat the decaying matter from dead plants and animals and help return nutrients to the environment. These include plants like fungi and animals like the vulture. In moister environments, bacteria also help in decomposition.
Source Citation: U·X·L Encyclopedia of Biomes. U·X·L, 2000.