Drop an egg on the floor, and it will break.
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The chances of the egg reassembling itself are so improbable as to be effectively zero. The useful energy expelled through your inadvertent inelastic collision cannot be retrieved, even if you feed it to your dog or cat or let the microbes have it. You have increased the entropy of the universe.
Scramble an egg, and eat it for breakfast. Or better yet, feed it to a chicken, who will use it to make another egg. But only part of it will be used in new egg production.
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Most of it will not be used. Furthermore, you and the chicken contribute waste products to the universe, in the form of perspiration or urine. Waste products of sewage and garbage can be used to produce more energy such as for fertilizer or
biogas plants, but again, this is inefficient as you will not recover all of the original useful energy put into it to make it. So while living things decrease entropy, living things plus their waste products yield a net increase of entropy.
If you are further curious about how waste is helpful in the entropy battle, the biogas series mentioned above also has articles on the construction of the plants, how they process the material, and the chemical reactions involved - these are not for the squeamish!
Life contributes to a net increase in the entropy of the universe, and thereby heat death. But is this still true when a living thing dies? Also, what is the shortest way to summarize the laws of thermodynamics? Both of these questions will be explored in part four.
