Energy Transfer

Energy transfer describes the changes in energy (a state function) that occur between organisms within an ecosystem. Living organisms are constantly changing as they grow, move, reproduce, and repair tissues. These changes are fueled by energy. Plants, through photosynthesis, capture some of the Sun's radiant energy and transform it into chemical energy, which is stored as plant biomass. This biomass is then consumed by other organisms within the ecological food chain/web. A food chain is a sequence of organisms that are connected by their feeding and productivity relationships; a food web is the interconnected set of many food chains.

Energy transfer is a one-way process. Once potential energy has been released in some form from its storage in biomass, it cannot all be reused, recycled, or converted to waste heat. This means that if the Sun, the ultimate energy source of ecosystems, were to stop shining, life as we know it would soon end. Every day, the Sun provides new energy in the form of photons to sustain the food webs of Earth.