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. In the deciduous forest, as elsewhere, the food web consists of producers, consumers, and decomposers. An analysis of the food web shows how energy is transferred within the biome.

Green plants are the primary producers in the forest. They produce organic materials from inorganic chemicals and outside sources of energy, primarily the Sun. Trees and other plants turn energy into plant food.

Animals are consumers. Plant-eating animals, such as grasshoppers and mice, are the primary consumers in the forest food web. Secondary consumers eat the plant-eaters. Tertiary consumers are the predators, like owls, foxes, and tigers. They are carnivores. Humans fall into this category. Humans are also omnivores, which means they eat both plants...