Humans seems to need external energy by Gail Tverberg Strange as it may seem, humans seem to have evolved in a way that we have a need for external energy, such as energy from burning wood or fossil fuels. While the evidence is not 100% certain, it appears that we learned to use fire long enough ago that it is now necessary for our food to be cooked. Otherwise, we would need to spend half the day chewing our food, and we would not be able to do much besides gather food and eat it. (People on raw food diets get around this issue by using a blender , which also uses external energy.) There are other evolutionary deficiencies as well: How do we deal with our lack of fur? How do we deal with our evolutionary dental problems? How do we deal with "survival of the fittest"? We don't think of humans as having instincts, but like dogs, we have a tendency toward hierarchical behavior, and this affects our need for (or at least "want for") external energy. In this post, I will explain how these and other evolutionary issues relate to mankind's need for external energy, such as wood, or gasoline, or electricity. Human's Need for an Outside Energy Source According to Todar's Online Textbook of Bacteriology , energy is important for all living organisms. Plants and animals literally can't live without a source of energy. Except for humans, plants and animals get all the energy they require