Civilization and evolution. Within living memory, people used to cluck and sigh and say that since we all lived in a civilized world, we were going soft. Since we didn’t have to run up trees to get away from hyenas any longer, we were losing the ability to go up trees quickly. Our muscles were getting puny, our eyesight dim and our wits were in decline. I have not heard such remarks for many years, possibly because it is now clear that civilization is not such a soft life after all. Try getting a middle class job any longer. There are more rich people than ever and more poor people, but the middle class virtues including establishing financial competence on the merits of ones own skill and effort seem to be yielding only rare success.
“Look at the stupid, the sickly and weak,” was the cry. “By leaving them to breed, we are taking the whole race (that’s what we used to call the human species) down.” Ixnay. If the gene pool was getting weaker and dumber, then life should be easier for those with strength and intelligence and the desire for independence. Not many believe that any longer. Besides, such sentiments when applied to civilization always seemed to me, forgive me, uncivil.
But let us look at a few of the issues, muscle mass, fat and eyesight, in light of the fact that people have gone about as far as we can go in terms of accumulating genetic complexity. Then we will look at the implications of what might happen to us in the far distant future, a future we can have if we are willing to make some changes, and see what a cushioned life might do to us.
As far as muscle mass goes, you wouldn’t really want a whole lot more. There would be a metabolic cost to building it, of maintaining it and of lugging it around. If starvation is a significant risk, as it still is for a large fraction of the human population, more muscle would be a hindrance. Certainly some extra muscle is a usable source of energy; if you are muscular and starving, your body can burn the substance of your muscles and continue to function. One of the serous metabolic costs for a human is feeding the brain. The brain is the ultimate finicky eater. It will take nothing but sugar for energy. Sugar can be reclaimed from protein if somewhat inefficiently and cannot be obtained from fat stores. But in fact, when a person is starving and close to the end, the fat stores have been burned up along with the proteins. I have never heard of a person going into convulsions from hypoglycemia from starvation and still having ample fat, at least with an otherwise healthy metabolism.
On the other hand, more muscle mass should not at least in principle require more genetic information. There must be a feedback loop that governs overall muscle mass for a given level of activity, and resetting that loop should not require more genetic code.
Which brings us to fat. Yes, lots of us, are fatter than is good for us, and that is getting worse. But in terms of avoiding starvation, particularly if one is going to remain active and stir around looking for food, fat is lighter for its energy content than is muscle. A pound of fat will carry you farther on your walk than a pound of muscle. So if resources are scarce and unreliable, having a tendency to get fat is no bad thing, contemporary overdoing of it notwithstanding.
In fact, fat has another advantage. It is better at keeping us warm. A human has far greater resistance to cold than an ape. We have populated colder climates. Some of this has been accomplished of course by the fact that we can make clothing. But the Patagonians when first seen by Europeans in Tierra del Fuego had no clothing. The temperature in the summer, according to Wikipedia, rarely goes above 50 degrees Fahrenheit in the summer and averages about 30 in the winter. It probably was not much fun, but the people survived.
And yet another advantage to fat involves the fat of your seat. There is an accumulation there that lets you sit and work for long hours. That is no doubt an advance that has occurred since the advent of manual skills. But again the change has probably not required a significant investment in increased genetic investment.
Also, nearsightedness probably does not require any greater investment. And it is not such a bad thing. Of course in a dangerous environment it is good to have a least a few members of your band who can spot threats or opportunities at a maximal distance. But in a showdown you need your best vision to be within arms length. That is not just because you will probably be reaching for a weapon. A hawk may be able to spot its prey at a mile away, but it would be at a severe disadvantage if the prey became invisible in the last couple of feet.
And of course, for working with the hands, a touch of nearsightedness means the eyes are relaxed at a comfortable working distance. So along with fat bottoms, nearsighted eyes may seem unglamorous but in real life they are handy.
So it is a wash, at least for the characteristics we have looked at. We have not become puny, fat and dim of vision because the gene pool is getting weak. The gene pool is doing its job.
I am sure there are changes that have indeed made us less fit to live a primitive existence, but I find them less than obvious.
But suppose we enter a future where we truly are less fit to survive in the wild. Actually, we have long been unfit to live a solitary existence in the wild. We have survived because we established communities of mutual support. Depending on others is nothing new.
We might get worse at living without an advanced technology. Suppose some synthetic diet were developed that was the ideal food for the human, maximizing life and minimizing the metabolic work of exploiting it. And further suppose that in time we were able to survive on nothing else. It was limit yourself to the hideous glop or die. No more fresh fruit. No more catching fish or working in the garden for something to add to a meal. Do not even dream of recreating a more traditional life style.
That would be a bad thing, would it not? Well, certainly from an aesthetic standpoint. It would still be better than living as a Patagonian, but life without hope of a peanut butter sandwich sounds harsh indeed.
On the other hand, it would mean we had unloaded an enormous amount of genetic complexity. It might mean we would be able to survive in larger gene pools, but if we are going to live anything like long enough to see progress like that, we are going to have to come to grips with limiting gene pool size in the very near future.
In turn, reducing our complexity and thus our mutational burden would mean that we could accumulate genes or the fine tuning of genes that we simply cannot now afford. It would mean we could advance again, evolve, and become better in ways we can only guess.
Civilization does not betray evolution; it is the handmaiden to evolution, and that maiden has been serving us well for a very long time.
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