How does the second law of thermodynamics relate to the energy pyramid?

Question

Olivia Akins · Accepted Answer

The second law states that useable energy always decreases. In the energy pyramid 90% of useable energy is lost in each level

Because the usable energy in any energy transfer always decreases due to entropy, not all of the energy stored in a plant is converted to ATP in the herbivore when it is consumed by a first level consumer (this is the second law of thermodynamics). The organism then has to expend a great deal of energy simply to keep up its own vital functions; this energy is "lost" to heat and becomes unavailable for use by that organism or any other organism. Merely 10% of the energy stored by the plant producers remains available for utilization by the predator (carnivore) after the first level consumer is devoured by the second level consumer. One universal property of the second law of thermodynamics is that there is always an increase in the amount of disorder in the universe.

Caleb Allen · Answer

undefined The second law of thermodynamics states that in any energy transfer or transformation, the total entropy of a closed system will always increase over time. This law relates to the energy pyramid by illustrating the flow of energy within ecosystems. In an energy pyramid, energy is transferred from one trophic level to the next, with each level representing a decrease in available energy. This transfer of energy follows the second law of thermodynamics because as energy is passed along the pyramid, entropy increases due to the loss of energy as heat at each trophic level. Thus, the energy pyramid reflects the concept of entropy increase in accordance with the second law of thermodynamics.