The twentieth century has brought with it many advances. With those advances, human lives have changed dramatically. In some ways life is worse, but mostly it is better. Changes in food preparation methods, for example, have improved our lives greatly.
The convenience of preparing food today is amazing. Even stoves have gotten too slow for us. Microwave cooking is much easier. We can press a few buttons and a meal is completely cooked in just a short time. People used to spend hours preparing an oven-cooked meal, and now they can use that time for other, better things. Plus, there are all kinds of portable, prepackaged foods we can buy. Heat them in the office microwave, and lunch at work is quick and easy.
Food preparation today allows for more variety. With refrigerators and freezers, we can preserve a lot of different foods in our homes. Since technology makes cooking so much faster, people are willing to make several dishes for even a small meal. Parents are more likely to let children be picky, now that they can easily heat them up some prepackaged macaroni and cheese on the side. Needless to say, adults living in the same house may have very different eating habits as well. If they don't want to cook a lot of different dishes, it's common now to eat out at restaurants several times a week. Healthful eating is also easier than ever now. When people cook, they use new fat substitutes and cooking sprays to cut fat and calories. This reduces the risk of heart disease and high cholesterol. Additionally, we can buy fruits and vegetable fresh, frozen or canned. They are easy to prepare, so many of us eat more of those nutritious items daily. A hundred years ago, you couldn't imagine the process of taking some frozen fruit and ice from the freezer, adding some low-fat yogurt from a plastic cup and some juice from a can in the refrigerator, and whipping up a low-fat smoothie in the blender!
Evolution of sleep
Sleep is very ancient. In the electroencephalographic sense we share it with all the primates and almost all the other mammals and birds: it may extend back as far as the reptiles.
There is some evidence that the two types of sleep, dreaming and dreamless, depend on the life-style of the animal, and that predators are statistically much more likely to dream than prey, which are in turn much more likely to experience dreamless sleep. In dream sleep, the animal is powerfully immobilized and remarkably unresponsive to external stimuli. Dreamless sleep is much shallower, and we have all witnessed cats or dogs cocking their ears to a sound when apparently fast asleep. The fact that deep dream sleep is rare among pray today seems clearly to be a product of natural selection, and it makes sense that today, when sleep is highly evolved, the stupid animals are less frequently immobilized by deep sleep than the smart ones. But why should they sleep deeply at all? Why should a state of such deep immobilization ever have evolved?
Perhaps one useful hint about the original function of sleep is to be found in the fact that dolphins and whales and aquatic mammals in genera seem to sleep very little. There is, by and large, no place to hide in the ocean. Could it be that, rather than increasing an animal’s vulnerability, the University of Florida and Ray Meddis of London University have suggested this to be the case. It is conceivable that animals who are too stupid to be quite on their own initiative are, during periods of high risk, immobilized by the implacable arm of sleep. The point seems particularly clear for the young of predatory animals. This is an interesting notion and probably at least partly true.