* Metabolism: Organisms use a significant portion of their energy for basic life processes like respiration, growth, and movement. This energy is released as heat, which is lost to the environment and cannot be used by other organisms.
* Waste: Organisms excrete waste products like urine and feces, which contain energy that is not passed on.
* Undigested Food: Not all the food consumed by an organism is digested and absorbed. This undigested food is eventually eliminated and represents a loss of energy.
* Death and Decomposition: When organisms die, they decompose and release energy into the environment. This energy is available to decomposers, but not to higher trophic levels.
In summary, the 90% lost energy is primarily converted to heat, lost as waste, or unavailable due to undigested food and decomposition. This energy is not passed on to the next trophic level, creating the pyramid structure of energy flow in ecosystems.
