We all know that humans evolve very slowly. It takes thousands and thousands of years before we could even notice a difference. Technology and our knowledge of human physiology, though, are evolving at a much faster rate with differing implications for humankind. Things are changing very fast in our current day and age, and some of these things that I wish to discuss include: the shift in how study diseases among a population of the medical community and societal structures in place far different than what existed for the majority of human evolution, and the development, increasing accessibility.
Evolutionary biology as a tool for studying disease, also known as Darwinian medicine, is a relatively new approach to studying and fighting diseases. What Darwinian medicine does, is it shifts the scope of medicine from studying specific diseases to studying the traits that make us susceptible to certain diseases. We must, of course, look at these traits from an evolutionary perspective and try to identify why we evolved this trait in the first place. At that point we can better understand the functionality of specific traits and devise medical practices that remove the prevalence of diseases while limiting the possible negative affects. It also is important to realize that we didn’t evolve to become pure figures of health throughout our lives, but we evolved to have the best chance of living through our reproductive years.
The next point I wish to discuss doesn’t deal as much with recent human evolution, but societal evolution that could potentially cause humans in developed countries to evolve differently than humans in poor countries. I’m specifically talking about the (over) availability of food for those in rich countries. Natural selection among humans has almost always favored those of us that can eat large quantities of food at once. This is because for most of humanity food was relatively scarce. Because of the lack of food for many humans, those that had a desire and ability to eat and store more food when it was available gave them a better chance of surviving times when food was scarce. In rich countries today though, the same traits that would increase a man’s chances of survival as a hunter and gatherer have the exact opposite effect. These traits today greatly increase the likelihood that a person will suffer from atherosclerosis and die sooner than someone who doesn’t overeat and store as many fats. After realizing this information, one might be tempted to think that those in rich, developed countries will likely evolve and lose this trait over many years, while those living in poor countries would benefit from maintaining this trait. Personally, when I first was reading the information, that was the next logical step that my mind jumped to. This is not the case, though. We have to understand that atherosclerosis affects the elderly at a much higher rate than young people. Basically, people very rarely die from heart attacks before having ample time to reproduce. Because of this, a person with a high risk for atherosclerosis would be essentially just as likely to pass on their genes as someone without a high risk for atherosclerosis, and therefore natural selection does not apply.