Humans - Are We Still Evolving?
Like every other living organism on the planet, humans evolved according to natural selection. From the fossil record to mitochondrial DNA to vestigial structures, not only is the evidence in favour of evolution overwhelmingly strong but many features of our bodies only make sense in an evolutionary light. This is important because it compels those who favour some kind of intelligent design to admit that we have been designed in such a way that it looks as if we evolved according to natural selection. God’s divine prank. Tricksy deitieses.
But, even though we did evolve this way, we are at a point in that evolution now (and have been for some time) where it makes sense to ask whether we are still evolving the way Darwin indicated over a hundred and fifty years ago. Are we still playing the game by Darwin’s rules?
First, we need to clarify exactly what the question is referring to, namely, evolution by natural selection. Evolution is simply change, although it does imply change in a ‘forward’ direction. Obviously, this is not necessarily teleological in nature, but it certainly suggests an improvement over what came before. How do we measure improvement? Simple; better able to survive and reproduce. The longer beaks of certain birds are an improvement over the shorter beaks of their ancestors not because there is something ‘better’ about long beaks but because it allowed them to access food they wouldn’t have been able to otherwise.
The idea that animals (including humans) evolved to their current forms has been around since the time of the Ancient Greeks at least. The real genius of Darwin’s discovery lay in his identification of the mechanism behind evolution, that is, how evolution took place. The answer is, of course, by natural selection. The beauty of natural selection is the deductive certainty of its conclusion. (1) If the population of an organic species is genetically varied (it is), (2) if those variations are passed on to the offspring (they are) and (3) if some of those variations produce enhanced ‘fitness’
So far, so good. This theory works in animals quite nicely. But what about modern-day humans? Is this pattern still true for us? I submit that it isn’t and there are a couple of reasons I think this. The first is that the features which allow us to successfully reproduce are often not genetically inheritable. No lioness turns down a potential suitor because she doesn’t get along with his mother or because she has a different belief about what happens to her after she goes to that big savannah in the sky, and yet these are some of the things that do matter to us when choosing a partner. Genetic factors that strongly influence size and appearance don’t necessarily hold as much sway as they used to. We are just as likely (if not more so) to choose a ‘mate’ based on things like our prospective partner’s bank balance, job, religious beliefs, habits, family, friends, etc.; none of which are significantly genetically determined.
Even personality traits and other aspects, like intelligence, that one might argue are susceptible to a degree of genetic influence, are far from determined. We may have a genetic tendency to some disposition but our extensive, pervasive and complex culture, unparalleled in the animal world, means that nurture undoubtedly plays a significant role in our development. In addition, once we reach a certain age, we find ourselves able to make conscious decisions to improve, enhance, get rid of, or change almost any aspect of ourselves we don’t like. If I have a short fuse (say, due to genetic and/or environmental influences), absolutely nothing stops me from recognising this and working on improving my patience.
Note that although all of the features mentioned above do result in ‘fitness’ in the evolutionary understanding of the word, that is, in the sense that they might make us more desirable to members of the opposite sex (and therefore more likely to marry/reproduce), the point is that they are not genetically transferrable and therefore don’t fall under the auspices of natural selection. Take religious belief. It is overwhelmingly likely that the children of Christian parents will also be Christian and go on to produce more Christian babies. Can’t we argue that this operates in the same way as natural selection and just expand Darwin’s understanding of the term to include this non-genetic example of survival of the fittest? I don’t think so.
Natural selection is natural. It is a) a specifically biological phenomenon and b) something we don’t have a say in (I can’t choose my height or skin colour). If it doesn’t match these criteria, in my opinion, it’s just too much of a stretch to be called natural selection. In short, the Christian parents’ children aren’t Christian in the same way that a white snow leopard’s cubs have white fur.
The second and even more telling reason I think natural selection is no longer at work in humans is the culture we have created for ourselves surrounding the family unit. For natural selection to work, the fittest individuals must leave behind more offspring than their competitors. We see this play out everywhere we look in the wild. During mating season the females all have babies and the males all vie for mating rights. The winner reserves the lion’s share (no pun intended), if not all, of the females for himself and diligently proceeds to create more offspring that bear his traits and characteristics. And they’ll do this the next mating season, and the one after that, and every mating season they are physically able to.
Contrast this with humans who, far from having babies every ‘mating season’, may have anywhere from five (in a relatively large family) to zero children over their entire lives. In fact, people often decide not to have more (or any) children because raising them is expensive or parenthood conflicts with other goals they have. No tiger makes this calculation come mating season, weighing up the pros and cons of conception; “Hmm, it’s one more mouth to feed and I was really hoping to focus on my career…”
Even more importantly for our question concerning natural selection, the custom of monogamy and the associated conception of the basic family unit mean people seldom have multiple children with multiple partners and even if they do manage such a feat, they certainly don’t do so on anything like the scale they would need to for natural selection to operate in any meaningful way.
One possible exception to this might be the practice in some cultures of taking multiple wives/husbands. But again, it is difficult to tie this to any biologically inheritable features. Taking multiple partners (and, of course, having children with them all) would seldom come about because someone has some kind of adaptive feature that makes him or her “fitter” than their competitors. It would probably come down to, in most cases, something like money, power or status.
Does this mean we are special, perhaps less animal-like? To the consternation of people like John Gray, I would argue that yes, it does. Not in the sense that some deity has found favour with us and made us the centre of His or Her concern, but in the sense that consciousness has bequeathed to us a world completely different from that of our animal cousins. Yes, chimpanzee society is complex and dolphins reportedly have sex for pleasure but no animal has come anywhere near to building the unbelievably complex culture full of intricate and detailed customs that we have surrounded ourselves with.
And how does this let us rise above evolution? Principally because we no longer have to compete to survive anymore. Mating rights no longer go to a select few, as they do in the rest of the animal kingdom. Even though I am not the “fittest” of my species, I have almost the same opportunities to pass my genes on to the next generation as a “fitter” candidate because human society has progressed the way it has, that is, in a direction where mere survival can almost be taken for granted and my failings no longer mean that I will lose out on a chance to ‘breed’. There is almost nothing about me that would (or could) hinder me creating as many little Nathans as a more impressive human specimen, an ‘Ubermensch’ say, could create little ‘Ubermensches’.
For example, excellent vision, an improvement in almost any other animal and one which could be expected to yield a significant competitive advantage, contributes nothing to humans because poor vision is no impediment to survival/reproduction. It just means I need glasses, or even better, contacts, or even better, eye surgery. But I’m short. Some women like short men. And in any case, I can make up for this in other ways, by being kind for example, (or even better, rich!).
In short, the world humans live in is so different from that of other animals that we are no longer subject to the same natural forces that govern their development (and used to govern ours). The rich, complex, societies and customs we have constructed for ourselves have created something we don’t see in any other species; culture.
Culture has seen us create artificial things without any ‘real’ value (such as pieces of paper with numbers on them) that influence our choice of mate, and place arbitrary limits on our social interactions (particularly those concerning families) which in turn constrain and restrict our abilities to transmit our genes into future generations.
The result of all this is that evolution by natural selection no longer carries the day for the human species. As unlikely as it may seem, and as contrary as it may be to the prevailing mechanistic, evolutionary, scientific climate, the conscious human animal has risen above at least one of the natural principles that still constrain every other animal on the planet.