An interesting discussion arose with one of my readers, about the evolution of the human species. My thoughts on this topic are rather well-informed, and I do hope they do not read like a lecture, but I really do feel it necessary to make very valid point: Humans are no longer evolving in the traditional sense.
Let us first review the standard model of evolution — mutations occur in a predictable rate within a genome, sometimes caused by simple copying errors, sometimes by disease or environmental factors (like toxic waste in the old Godzilla franchise). These mutations are either fatal, and therefore cannot be passed to offspring, or they are beneficial, and thus allow the organism to survive and pass this benefit to their offspring. Thus “new” conditions are either added or plucked from the gene pool.
There are only three factors that affect this process: environment, gestation and maturity times, and sexual selection.
The environment figures as follows: it may remove a mutation in an instant, or make one more favorable, as in the case of the moths during the Industrial Revolution. The species contained mostly light-colored moths, but a mutation formed so that a few moths had darker patterning. As factory soot collected on tree trunks, the white moths were eaten, until only dark moths remained. These dark moths became the only surviving members of the species and therefore passed on the trait. Now that species of moth is largely dark in color.
Gestation and maturity timespans are of vast importance. If a species takes many years to reach sexual maturity, and many months to spawn, then the species is very vulnerable to mass extinction. If a disease (or a very hungry monster) were to come along and kill off most of the children, there would be a large gap in procreation, and indeed an entire species could be wiped out in just such a way. To give some perspective, in only a few decades, the Black Death had decimated nearly a third of the population of Europe. The human race was not rendered extinct, because it has a robust immune system, and those who survived, had either innate or acquired immunity. Measures were taken (albeit silly measures like throwing cats in bonfires) to control the spread of the disease. So even many years later when the plague reappeared, it could not do as much damage as it did the first time.
Now we come to it: sexual selection. This is the species’ own thoughts of fitness — attraction. It is the mind of the creature directly controlling what genes are propagated. A bird looking for brighter plumage, a monkey looking for clean, shiny fur, a human looking for symmetry of features — it is all the same. These traits are now shown to be directly linked to more important traits, like overall health. You ask, what does that mean? I reply, that “body patterning” or the genes that control the duplication of features from one side to another, are also directly linked to how your organs develop. A person with two evenly space eyes are more likely to have higher functioning organs, perfectly constructed brains, et cetera. This does not mean “beauty” has anything to do with fitness, as it is quite possible for a human to be “ugly”, but have two perfectly level eyes.
Simon, you say, come to the point, if you please. How have humans stopped evolving?
Thank you, gentle reader, for sitting through this pontification. I needed to make certain we all understood how evolution works, so that we can discuss how it has halted for your species, since I know it is still a hotly debated topic and no longer is taught in many schools.
The trouble is your brains. No really.
You are now so smart that you have undone traditional evolution.
Allow me to explain.
Firstly, the environment. You have invented medicine — from pharmacology to surgery, you remove many of the maladies that might have killed off offending genes or inmate weaknesses. Now a person with asthma, who should never have lived to pass on this imperfection, can survive to sexual maturity, look pleasing enough to a mate, and procreate. Leading to a reemergence and growth of the “asthma” genes. This is of course, a metaphor, as to my knowledge, there are no “asthma genes”. The point is, medicine has made it possible for more of you to survive and sculpt the gene pool in an entirely unfortunate way. People rant and rave about vaccinations causing autism. That is utter tripe. Autism is not fully understood, but I’d be willing to wager that its seeming growth within the population is either because of statistical error or the fact that it is being bred into the population.
In any case, medicine has also made it possible for people who would not have been able to conceive, to do so, and bring fully functioning offspring into this world, for good or ill. Medicine has kept premature babies alive, has made it possible to preserve infants that would have been stillborn. Medicine is changing everything.
Then there is farming and the distribution of a greater variety of foods. Your ancestors ate whatever they could get their hands on in their particular region. There was no complex nutrition or sampling of the world’s cuisine. People scoff at things like lactose intolerance, gluten sensitivity, the seemingly large number of allergies that have appeared. They haven’t appeared. They always existed, but this is the first age in which a human whose ancestor evolved to primarily eat rice and fish can now eat wheat and cattle. Of course there will be more allergies.
Nutrition has literally changed the face and body of humanity in but a few generations. I can point out specific cases. I can tell you that it would have been impossible for the famous 300 Spartans to have such sculpted abdominal muscles as those depicted in that ridiculous movie. And I can go on and on, as you know, since food is my particular joy.
But we must move on.
We must discuss gestation and sexual maturity. Many adults would argue there is no sexual maturity, and while this is amusing, it is not true. The fact is, modern culture has shifted. People are getting older now — as in, living longer. They have unnaturally extended childhood. For most of your history, women were married off as soon as they began to menstruate, i.e. sexual maturity. They mated, had babies, and probably died in childbirth or soon after. This was the truth. But modern humanity is living longer and requires their children to have more expertise, more social responsibility. Now the young must go to school until they are 18, and must not be considered fully mature until their early thirties, it seems to me. Now it is not uncommon for a woman to wait until she is nearing the end of her mating ability to have children. Society has developed judgements against those who mate young. If a woman has a child while in high school, she is a whore. In point of fact, she is entirely normal and is doing precisely what her genes were patterned to do. It is society that has made it impossible for her to have a “normal” life.
Thusly, maturity and the gestation periods of human fetuses have ceased to matter. It is easy to have children, the time for doing so is extended and coddled by medicine, the diseases that would have annihilated fetuses are of no great concern. Infection no longer kills a young, frail mother after one child. In fact, it allows a healthy, well-fed, strong young woman to squeeze out several pups and raise them all into maturity.
This brings us to sexual selection. It is the only thing that still has a bearing upon how humans pass along their genes, and yet, not in the way you would imagine. Now you teach your children tolerance and respect. You socialize them to find all appearances and body types to be worthy of love and friendship. You train your children to admire the intellect. You heap scorn upon those who look for the pretty face and perfection of the body. These are all “good”, “noble”, “ideological” things, except that they interfere with standard evolution. Now it is possible for a person with a particular genetic deformity that would have been forcibly ejected from the population, to find a mate and procreate. Under the old ways, it would not have been largely impossible for a dwarf, a “lobster man”, or a conjoined twin to find a “normal” mate, and the heritable genetic flaws would have been bred out of existence. Now they are being reincorporated, now medicine is assisting them in staying alive.
Allow me to point out that I do not have a judgement upon this practice. I think it is, in many ways, very beneficial to the human race to record and understand the variety of human experience. This lack of darwinians evolution is in fact making you smarter — which goes to my point.
For many centuries every skin color remained closely controlled and linked to location. The “races” did not mix, because they hardly ever saw one another, and when they did, prevailing ideas of the “savagery” of the other prevented people from intermingling. But now there is global cultural, travel, the lust for experiencing life. Now you mix very well. Now genetic traits are being swapped in infinite combinations. People are evolving in their thoughts on one another and changing the appearance of the species.
So too is it true that your ideas of beauty have transformed. In the Dark Ages, a man looked for a woman of goodly size. She must be strong like an ox, with a pleasing amount of fat, large breasts were wonderful, but a large backside even moreso. She must be “curvy”. This is because skinny women could not survive. It was more important that she have good teeth and be plump, than that she be a walking skeleton with “bedroom” eyes. Now, the standards have changed. Women should have “thigh gap” and be able to turn sideways and vanish into thin air. But this goes both ways. For many centuries men exposed their legs, wearing tights, hose, shoes that showed off their ankles. A man’s legs were often the first thing people pointed out when giving a list of his finer qualities. Shapely calves were the “cat’s meow” to all the eligible females. Now humans seem to care less about legs and more about the “six pack” which is only helpful if a person intends to sit up and lie down regularly. And may I point out that large biceps directly interfere with the ability to swim.
In point of fact, I would be very pleased if standards of beauty reverted backward a bit. It is devilishly tricky to find anyone with a goodly amount of meat or fat on them these days.
So you see, you are not evolving. Mutations are not being bred out of existence or quashed by the universe. You are not at the whims of the natural laws. Instead, old mutations are not only surviving, but returning, standards are shifting. The one aspect that has any bearing upon how your genes propagate — sexual selection — is completely at the mercy of your ideas. And these ideas replicate over your populations with tremendous force. In many ways, they govern all that you do.
Human evolution is now only happening in the mind. Will it prove that you are too smart for your own good, I wonder.
This entire discussion brings up an interesting point: how have my species evolved. And the answer is somewhat profound. Upright hominids have been evolving and intermingling for 3-5 million years or so, with lifespans of about 30 years, minimal nutrition. If it has taken 3-5 million years to produce the 20,000 or so years of civilization humanity calls “mankind”, then take a moment to ponder this. If I am as ancient as I am, and have never once entertained mating, how slowly have we evolved? How long have we been here? Perhaps we did not evolve to mimic you. Perhaps you evolved to mimic us.
And I will leave you with that.