What is the difference between food chains and food webs? Food webs show the flow of energy from producers to consumers, and food chains show the flow of energy from consumers to producers. Food chains show a single path of energy in an ecosystem, and food webs show overlapping pathways of energy in that ecosystem. About ten percent of the energy is passed on to the next trophic level in food webs, but in food chains, about ninety percent is passed on to the next trophic level. Heat is lost when energy is passed on to the next trophic level in food chains, but in food webs, heat is not lost when energy is passed on to the next trophic level.