The End of Evolution

Whether one believes that evolution is factual or that everything was created on October 23, 4004 BCE is of no consequence, because there has been evolutionary change since 4004 BCE, but that may have changed within the last couple of centuries. It is possible that human evolution has been brought to a stop. I suspect that this hiatus will fail in the end, but it may have some ill effects, or this hiatus may simply turn out to be a different step in evolution. The specific matter to which I refer is modern medicine, which effectively has eliminated some of the mechanisms through which evolution had been operating.

More specifically, some people, who could not have survived because of genetically caused medical problems, are now living to become adults and sometimes passing on their genes that cause their disease. In addition to those conditions in the list below and on the linked list, many cancers are caused by genetic disorders that are triggered by other stimuli. By keeping alive people who would not be viable without major ongoing (or even constant) medical intervention and allowing some of those people to reproduce some of the results of millions of years of evolutionary improvement is being reversed.

It has been said that evolution ended when people started heating their places of habitation, but that was insignificant and other animals heat or at least insulate their places of residence. Many of the things that humans use are simply outgrowths of their evolutionary development, and the invented devices simply became additional tools for evolution. For example, humans invented cooking a long time ago. Initially cooking probably was a method for making carrion a little less likely to cause sickness, but cooking also led to the reduction in tooth size and made it more nutritious.

Cooking, building houses, mechanical transportation, and so on became tools for evolution and instruments for humans to do what they would have done anyway but a little more easily. Over the last couple million years humans have been slowly developing their tools and improving their methods for building houses. These things did not impede the biological systems, genes, etc. that are essential to evolution; they have been methods for evolution to operate or were until rather recently.

Humans had been altering their environment since the genus split from the other great apes, and humans are not the only species that alters its environment, so I don’t regard those changes as significant. Not even all medical practices do damage to the course of evolution. Chimps have been seen giving themselves medical treatments (see link below), and a variety of other animals eat foods that have specific medical benefits, but the extent of such treatments is rather limited (antibiotics and deworming mostly). Thus, it is perfectly reasonable to accept the medical industry as a natural outgrowth of the development of the human species, but I doubt the evolutionary value of treatments for various inherited genetic disorders that would cause death at an early age, if they were not treated. The outcome of such treatment is to help to perpetuate genetic characteristics that would not normally be passed on, because persons with those genes would not normally survive to reproduce. I am not suggesting eugenics, but I think that there has been too much medical care given to people who were not long for the world regardless of what might have been done for them. In addition, modern medicine has led to overpopulation.

I realize that there are people who think that the Earth could support even thirty billion people. But present evidence shows that it is difficult to have seven billion humans alive at once. The ability to produce adequate food for that many people is marginal at best, and, if the people who worry about climate change are right, then the resources to feed even the present population will not be available in the near future. A guess of how many humans the Earth could support effectively and with a safety cushion would be no more than two billion, roughly the Earth’s population in 1875. Although there were famines from time to time; there was adequate food production nearly all of the time. The places where there were famines had been developed and civilized for a long time and usually had local populations that pushed the local economy to its limit and any significant problem in food production resulted in a famine of some severity. Or famines were created by outside interference, as was the case in Ireland in the 1840’s. Famines were also created by invasions, and there have been periods of climate change in the past that led to crop failures; this happened during the period when the Little Ice Age was starting, resulting in cooler, wetter weather in some places, such as France where it cause crop failures. During the same era the American Southwest became dryer, and that led to the abandonment of the Anasazi cities.

During the period from 1725 (pop. 1 billion) to the present (pop. 7 billion) medicine has gone from unsanitary bleeding and other non-productive activities to being pretty darned advanced and effective, and I would contend that the improvements in medicine have been the principal cause for the increase in population. Infant and childhood mortality has gone from almost fifty percent to about ten percent, and people die in great numbers at ages greater than sixty now.

The term “sustainability” has become popular in the last few years, and I am proposing a way to make human life on Earth sustainable. The Green Revolution was wonderful in its way, but it wasn’t sustainable, and many of the agricultural practices and plants introduced as parts of that program have been abandoned in the last forty years. Intensive farming is not sustainable, and soil is deteriorating around the world; we have been eating that soil. The sustainable level of population probably is in the range of one to two billion. Returning population to that level quickly will be impossible, unless we do have a great pandemic, something on the scale of the Black Death of the Fourteenth Century worldwide. There isn’t a high probability of such an event, but it may happen. In the absence of such an event, or a major war, limiting the extent of medical activity would slowly reduce the population to a sustainable level.

The climate change alarmists worry about changes that may take place, but the problems that already exist are just as bad, and they are real, not theoretical. Thomas Malthus has consistently been shown wrong since he first came up with his theory (1798), and humanity may dodge the bullet again, and it is conceivable that something unexpected will come along, but animal populations are well known to crash when population density reaches a level that is unsustainable, and the crashes take a variety of forms from pandemics to mass migrations to the occasional mass insanity. We do not have the necessary perspective to be able to see whether there are effects at present that may be viewed as part of a population crash in several hundred years, after population has stabilized at one and a half billion.

Careful consideration as to what medical procedures ought to be used to keep who alive will almost certainly take place over the next few hundred years. We can expect that reasonable and valid decisions will eventually be made, and it is possible that repairing genes that produce disorders may become routine, not may but almost certainly will become routine, but until then we will be retaining genetic code that leads to the devolution of the human species, unless we make some hard and cruel decisions soon. If we don’t make those decisions, then there may not be people who will be capable in the future.

While I do favor limiting the use of medical procedures, I have a distinct feeling that this post will look completely silly in a couple hundred years, or sooner, because we will have simple and easy genetic repair, interstellar travel, and a few other of those things that futurists have predicted, but the “Singularity” will never happen. I am working on another post regarding probability; that doesn’t apply well to pure speculation, but it suggests that past records are the only standard that we can quantify with much confidence. And that suggests that humanity will continue to make Thomas Malthus wrong.


Links
Why Chimps Eat Dead Wood and Other Plants
http://news.discovery.com/animals/wh...ith-111129.htm
Other animals taking natural medicines
http://www.cracked.com/article_19686...-medicine.html

List of Genetic disorders
http://www.genome.gov/10001204
More common disorders
22q11.2 deletion syndrome
Angelman syndrome
Canavan disease
Charcot–Marie–Tooth disease
Color blindness
Cri du chat
Cystic fibrosis
Down syndrome
Duchenne muscular dystrophy
Haemochromatosis
Haemophilia
Klinefelter syndrome
Neurofibromatosis
Phenylketonuria
Polycystic kidney disease
Prader–Willi syndrome
Sickle-cell disease
Tay–Sachs disease
Turner syndrome
http://en.wikipedia.org/wiki/List_of_genetic_disorders
The End of Evolution
http://vega.org.uk/video/programme/13