The Future of Human Evolution and Why We Must Eventually Play God

Over the past 4 billion years the process of natural selection, through its method of patient, plodding persistence has gradually honed us Homo sapiens into the remarkable species that we are today.

Yet this same blind, unthinking mechanism also poses a seldom considered, yet very real problem to the future of our kind which could, if left unchecked, pose a serious threat to our continued prosperity.

In this article, I will illustrate the necessity of our eventual scientific manipulation of the human genome, in order to prevent the gradual deterioration and loss of many vital human traits.


I often find myself looking at a person – and glimpsing, for a few profound moments, their true, atavistic nature – realizing that they are but a single branch of the sprawling tree of life – apart, somehow, from other organisms on earth – yet still intimately, inextricably connected with their evolutionary past.

Surrounded by man-made structures of concrete and symmetry; isolated in our hermetic paradise from the dangers of nature, it can be so easy to forget that we too are mere animals – forged by the same brutal environment that also gave rise to sharks, rats, and lions.

Similarly, it is easy to lose sight of the fact that we are still very much under the sway of the biological mechanisms that allow for the process of natural selection to occur – namely, the small, random mutations of our genes (as well as the recombination of genetic material via sexual reproduction) from generation to generation. This process has not somehow magically ceased since our supposed decoupling from the rest of nature – and we are thus still subject to its influence.

This then motivates the question: what kind of human phenotypes might be altered in the future, given our current swaddled evolutionary environment of safety and abundance? What traits might provide one human with a survival/reproductive advantage over another, and so be selected for?

It turns out, this is very difficult to conjecture about, simply because it is almost impossible to predict the changing landscape of human existence over the coming decades, let-alone centuries. Will our survival come under threat from some unforeseen environmental change – perhaps favouring those humans with, say, an improved respiratory system? Will the dynamics of sexual selection be altered to any significant extent – leading for example, to the predomination of men with small noses and large beards? Who knows?

Yet despite this uncertainty, it is actually possible to make a few predictions with some degree of confidence – and these are each based on the same principle:

‘Relaxed Selection’ – AKA ‘Use it or Lose it’

In order to illustrate the principle, we’ll first consider the Kiwi bird, which is native to my country of New Zealand.


The Kiwi is presumed to have flown to New Zealand some millions of years ago, whereby it found itself happily ensconced upon a peaceful little island that was utterly devoid of predators.

The Kiwi was now able to roam the terrestrial realm (which would have been a mortally dangerous activity in its former biome) with sheer impunity – gorging itself on the multitudes of insects that abounded the forest floor.

The birds had soon completely shunned the sky and the trees – and so too their need to fly.

Today, the wings of the now flightless birds are almost non-existent – having become a pathetically stunted remnant, about the size of a thumb. With no environmental pressures to select for wings, they were at the mercy of what is known in evolutionary biology as ‘relaxed selection’. ¹

Another case of relaxed selection is observed in deep-sea fish, which live beyond the purview of sunlight, in pitch-blackness. Without the need to see, their eyes have deteriorated into useless globules, lingering uselessly on the side of the fishes’ faces as an ironic wink to their past glory.

We can explain the mechanism through which a phenotype gradually becomes obsolete by considering what’s happening from the point of view of the genetic code:

Given that random mutations within the DNA of successive generations of a species are inevitable, the genes that give rise to any given phenotype will eventually develop ‘errors’.

In the case of phenotypes that are important for the creature’s survival/reproduction, these errors would die off with those individuals unfortunate enough to have inherited them – leaving the surviving generations error-free.

Conversely, for phenotypes that lack any selection pressures (such as wings, in the case of the New Zealand Kiwi), the errors will continue to accumulate and propagate, as father passes it on to son, and so forth – over time rendering the trait completely defunct.²

A thoroughly interesting 1997 experiment showed precisely this phenomenon.

The experimenters began with a population of fruit flies, which were kept for 30 generations under ‘relaxed selection’ conditions.


In each generation, male and female flies were assigned randomly to pairs, and each fertile pair contributed a son and daughter for the next generation – thus any type of sexual selection was made impossible.

The flies were allowed to live in conditions of luxury – with ample food at hand, and no predators to fear. For these flies, life was good – they wanted for nothing, and so natural selection loosened its guiding reins on certain of their genes.

What would happen then, if they were to be reintroduced to ‘the real world’ – where life for a fruit fly isn’t quite so comfortable?

As anticipated, each subsequent generation from the experiment was less apt to survive than the one before it.  Relaxed selection had taken its toll.

So what does this mean for us?

Our lives, much like the fruit flies in the aforementioned experiment, could well be considered luxurious.

In this age of modern technology and medicine, many genetic handicaps that in the wild would have spelled certain death, are now little more than slight inconveniences.²

Consider the human eye, which has maintained almost that same complex structure for millions of years – its genetic code so sublimely wrought that natural selection has seen it preserved and propagated ever since it was perfected. Any unfortunate offspring whose ‘eye genes’ weren’t quite up to spec would have had a difficult time distinguishing predator from prey, and consequently their malfunctioning genes were unlikely to have been passed on to the next generation.

But now, in the modern era, if a genetic ‘error’ happens to impair a person’s eyesight, they can simply (in many cases) seek the help of an eye doctor, and slap on a pair of prescription glasses or contact lenses.

Their genes are no less likely to propagate into subsequent generations than their neighbor with 20/20 vision – since they will be just as capable of surviving long enough to reproduce and raise their children.

Over time, the genetic errors associated with poor eyesight could therefore aggregate within the genetic pool of human populations. So how many generations before we’re all stumbling around in a bleary-eyed haze?

The same principle applies to any other human faculty that, should it experience a deleterious genetic mutation, can be either artificially aided by modern medicine, or simply has no bearing on survival and reproduction in our present environment.³

Hearing, smell, taste – even certain aspects of intelligence – none of these are safe. The selection pressures that would once have fostered these abilities – dangerous predators, the need to locate and recognize edible foods, the need to memorize a plethora of plant species – are now gone, rendering us, to a certain extent, fruit flies in a cage.

Assuming that human-kind is able to improve, or even simply sustain its present environment of relative comfort, then it is not a question of if relaxed selection will begin to manifest disabilities in future generations, but when.

It is imperative then, that we eventually develop a means of tweaking our own genetic code – of playing God – so that these most revered and essential human capacities can be safeguarded, for the benefit of our collective future.

A supplementary write-up for this article has also been written here.

[1] It should be noted that in the case of the kiwi (and deep-sea fish), along with many others found in nature – there can in fact be selection pressures that actually cause the losses – for example, as a means to reduce unnecessary energy expenditure of the organism. Strictly speaking then, the loss of traits in such cases are not solely caused by relaxed selection.

[2] I’ve gone into some interesting detail about human sexual selection regarding disabilities here (short article)

[3] This addendum also addresses another detail that was overlooked in this article – that there remain human populations for whom life is far from easy, and who would not experience the effects of relaxed selection to anywhere near the same degree as those in first-world countries.





  1. (I excuse for every spelling/grammar mistake I make in the course of this comment. English is not my native language. Feel free to answer in German :P)

    Your whole argumentation is very very dangerous. Just mentioned as a sidenote, I feel reminded of the argumentations used to support eugenics in the early to mid 20th century.

    First of all, you should not forget that humanity does not have the ability to survive in raw nature and therefore creates a cultural sphere which is safe to live in.
    There have never been the typical animalistic specialisations (I dont know how to write that) to live in nature, like the animals have you mentioned. What divides humans from animals and made them survive (not to mention unique) is not strength or fast reproducing, it is the fact that humans are zooi logois echomen, beings having the ability to speak and reason. And this ability is still needed in the cultural sphere coexisting with humanity since the beginning of humanity. Ignoring it leads to an incorrect understanding of what humans actually are, eventually creating irrealistic theories.
    You could argue that one would still be able “to survive” born without logos, that the cultural sphere would take care, but then ones “reproduction” would be very unlikely. In other cases, the pure existence of logos will always cause humanity to question or atleast behave to the sense of its being (Sein des Daseins).
    Aditionally, the easy documentation of thoughts and knowledge will make educational (and therefore cognitive) degeneration impossible, atleast as long as education stays affordable. The human intelligence was never needed to be as big as it is “to survive”, but if we look in the past, there is no noticeable degeneration of the average human intelligence. I would go as far as saying that the functional brain and it’s possibilities are not determined as much by genetics as it is by actually challenging and adapting it in ones lifespan.

    Now to the physical part. Yes, almost all physically impared humans “survive” in this cultural sphere, aswell as those with little impairs. But that something is not needed to survive does not mean that it is not needed to fit into society. Not fitting into society means less attractivity means less “reproduction”, spoken evolutionary. Small impairments like short sight are possible, but the “degeneration” will never be as fundamental as you might think.

    I don’t think humanity “must” ever “play God”. It will keep on researching genetics, it will make huge steps in cognitive sciences and boitechnology, but with other motivations than “surviving”.

    Thanks for your attention and have a nice week.


    1. Thanks for your comment Kara – your English is actually very good!

      You are very much correct in that what sets humans apart from other animals is their intelligence – but you should not ignore the important role played by our other (more animalistic) faculties in aiding our survival throughout the hunter-gatherer period and beyond.

      Contrary to what you have said, we did indeed (and still do) have the ability to survive in ‘raw’ nature – the ‘cultural sphere’ we have developed was by no means necessary for our survival, but it has certainly made the whole business of living much easier.

      Now, I’m prepared to accept the fact that ‘cognitive’, and other types of degeneration may not be likely (although I am not convinced by your argument as to why cognitive degeneration is ‘impossible’), but I’m afraid I don’t accept that relaxed selection will have NO detrimental impact on ANY of our faculties whatsoever.

      You said it yourself – “Small impairments like short sight are possible..” and this is really all I am trying to claim. Sure, I have speculated (perhaps with some exaggeration) about specific degenerations – but the crux of the argument I am making is that we WILL experience SOME negative effects due to relaxed selection – thus necessitating SOME kind of artificial genetic reversal of these problems.

      I have yet to hear any convincing arguments as to why there will be absolutely NO detrimental effects caused by relaxed selection.

      [By the way, we should understand that the effects of relaxed selection are statistical – it will not be the case that eventually ALL humans will suffer some kind of impairments, just a higher proportion of people than currently do.]

      Liked by 1 person

      1. Thanks for your answer!

        I can agree with you that there will be evolutionary changes, there already are some evolutionary changes in humanity taking effect, the most popular example might be the wisdom teeth and an increase of short sight (although it is not yet sure how much this increase is influenced by modern technology), but I rate the changes, as I said, to be minor, or atleast not to make genetic operations unavoidable. I, for myself, have the believe that technical enhancements will be the future, just because they do not pose as fundamental ethical questions as genetic research does.

        About the cultural sphere: Cultural sphere does not just mean living together. Tools and everything build to protect oneself even are parts of it. My point is that humans are neither naturally well equipped to hunt, flee, nor protect themselves, what lets them survive is the use of tools and communication.

        And furthermore, there is a way more interesting Questions we both could ask ourselfes: Does evolution have to end with the “perfect human”? Is there something like “good” or “bad” evolutional changes? In what position are we to judge about that?

        Have a nice weekend!


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