The Transfer of Energy Through the Food Chain Science Ecology Unit

Most of the chemical energy that is transferred from one organism to another in a food chain is lost to the environment as unusable heat. Less and less energy is available to each organism in the food chain.

About 10% of the food energy (in the form of chemical energy, glucose) made by the plant is available to an organism that eats the plant. Only about 10% of the food energy stored in herbivores (plant-eating organisms) is available to the next organism that eats it. See the 100 penny analogy sheet.

Some of the organic food energy is used to support life functions like growth and cellular respiration. Some of the energy is stored in wastes that are excreted into the environment. Bacteria, fungi, and other decomposers extract some of this energy, but most is lost to the environment as heat.

So, a constant supply of energy is needed to sustain living things in an ecosystem!