A large amount of energy in a food chain is lost into the atmosphere as?

Most of the energy in a food chain is lost as heat. This is because each time energy is transferred from one organism to the next, some of it is lost as heat. For example, when a plant converts sunlight into energy, some of that energy is lost as heat. When an animal eats the plant, some of the energy from the plant is lost as heat. And so on. By the time the energy reaches the top of the food chain, very little of it is left.