An isolated system contains negentropy if it reveals a possibility for doing mechanical or electrical work: […] A tank of compressed gas in a room at atmospheric pressure, a vacuum tank in a similar room, a charged battery, any device that can produce high grade energy (mechanical work) or be degraded by some irreversible process (thermal conduction, electrical resistivity, friction, viscosity) is a source of negentropy. […] If a living organism needs food, it is only for the negentropy it can get from it, and which is needed to make up for the losses due to mechanical work done, or simple degradation processes in the living system. Energy contained in food does not really matter, since energy is conserved and never gets lost, but negentropy is the important factor.