The first law of thermodynamics states that energy can be transformed from one state to another, but it cannot be created or destroyed. Taking this into consideration, what can be said about the energy transferred between levels in a trophic pyramid? All of the energy necessary for a trophic level is transferred to it from the trophic level below it. Because there is less biomass at each successive trophic level, less energy needs to be transferred at each successive level. Organisms at higher trophic levels consume only the energy they need from lower trophic levels. This leaves a "bank" of energy in lower trophic levels to support higher trophic levels when food is scarce. All of the energy is transferred from one trophic level to the next. Components that have no energy, such as light, are used to create the energy in the chemical bonds of carbohydrates. Some of the energy in a trophic level is converted to heat and is unavailable to the next level of the trophic pyramid. Some of the energy is held in one trophic level, and only the energy needed to support the smaller biomass at a higher level is transferred.