The energy flow of the food chain is cyclical: It starts in the producing organisms and goes to the decomposers, which turn the organic matter into inorganic, making the energy to be used again by the producers.
Along the food chain, about only 10% of the energy is transferred to the next trophic level. This is because much of the energy is lost, either in the form of heat, in maintaining the vital functions of beings or in reproduction.
Therefore, as energy passes from one organism to another, more food is needed to meet the energy needs of the next consumer.
