The energy flow through the trophic levels has a simple rule, only 10% of the energy is transferred to the next level, which is the so called ''10% rule''. The producers are the ones that produce the energy in the food chain, thus they have 100% of the energy available. Following the 10% rule, the next trophic level, the primary consumers, will get 10% from the energy of the producers. Moving on, the secondary consumers will get 10% from the energy of the primary consumers. These 10% represent one tenth from the 10% that the primary consumers got, or rather it is only 1% of the initial 100% of the producers.
