Energy is lost at each step in the food chain. The energy that animals get from their food is called food energy. Food energy can be measured using a calorimeter. The heat of combustion (heat released) when a substance burns is directly related to its food energy.
Animals need to eat other animals to get their food energy, so it seems reasonable that they would lose some of that energy as they do different things with it. For example, when an animal eats another animal and digests it, some of the energy goes towards digestion and some goes towards moving around after eating. Some animals can use more of their food energy than others.
Energy is lost at each step in the food chain because animals cannot use all of the energy from organic matter directly for growth or activity; some must be used for maintenance such as repairing damage from injury or disease or just maintaining life processes such as breathing and pumping blood around the body.
Last modified: August 14, 2022