Evolution

Assessing the Future of Human Evolution



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"What a piece of work is man! How noble in reason! How infinite in faculty! In form and moving how express and how admirable! In action how like an angel! In apprehension how like a god! The beauty of the world - the paragon of animals!"

William Shakespeare, Hamlet Act II Sc.II

In evolutionary terms, humans are already at the top of the tree. We have the biggest brains, proportionate to our body size. We have the finest motor skills and, most importantly, we have the greatest power of innovation. So where can we go next?

The subject of whether or not we are still evolving is one discussed over many a pint of beer. The most often heard opinion says we are not. We have already become top dogs so why would we need to evolve? Another commonly held opinion is that we are not evolving, have never evolved, but arrived on the planet as perfect as God intended us to be.

In any case, looking at the past shows that there has been a progression. Once upon a time, all hominids had much smaller brains than ours and walked on all fours.

Modern humans, Homo sapiens sapiens may have 'emerged' on the planet, in Africa, as long ago as 200,000 years ago. There are many difficulties with the dating, and often confusion as to the attributes of these early humans. Fossil evidence is fragmentary. Genetically, they were the same as us.

There were a few other species of genus Homo around then. Some of these were nearly as clever as us. H.neanderthalis, a 'branch' of our genus who we may have had a common ancestor with, made and used, tools. They were very simple items like hatchets and scrapers, cut from flint. But neanderthalis died out. Their brains were not as big as ours so they could not adapt. The same could be said of H.heidelbergensis which also coexisted with us for a time.

Our own species did not have an easy time of it. At one point, around 60,000 years ago, we were down to an estimated 2 thousand individuals. The Earth was very much harsher and colder in those days. No central heating or supermarkets. In some ways, H.sapiens sapiens was less well adapted to those conditions than earlier hominids like H. erectus. We were altogether less robust. The only thing we had going for us was our big brain,and our opposable thumbs, which we had been using for the previous 100,000 years. And yet we were struggling.

Then something happened. There was a 'great leap forward' in our sophistication. Palaeontologists find finer and more differentiated blades, cut by a more complex processes and made out of a greater variety of materials. In addition, there is evidence of art and craft, organized hunting and cultural gatherings. We also began to wander out of Africa, spreading relatively quickly to other parts of the world. Perhaps we were looking for warmer climates and better hunting, but certainly we were acting on our capacity to try new things.

So was this evolution? Or was it adaptation? Some researchers theorize that the great leap may have been down to the effects of one or two gifted individuals who learned and educated. Others say it was an adaptive response by a species under pressure. A species with a particularly large brain, well-developed bipedalism and opposable thumbs.

There have been many more big changes in the way H.sapiens has lived over the last 60,000 years. The change from hunter-gathering to agrarian societies being the biggest. The main driving force of change has been adaptation to environment, there is no evidence that any of it required change at the genetic level. We have every reason to believe that we will be able to adapt and survive as new circumstances arise in the future. But will we evolve?

Evolution was first described as a theory by Charles Darwin. In his most famous book, 'The Origin of Species', published in 1859, he says that evolution is caused by 'natural selection'. Put simply, there are two methods.

The first is to do with 'survival of the fittest', meaning those individuals who are better adapted to their environment are more likely to survive and pass on their attributes to their offspring. The second is 'sexual selection', ie our success in attracting mates.

These two can almost be considered irrelevant in modern society. We choose mates for all kinds of individual reasons. And our societies are such that no one is more adapted than another, we alter our environment to enable us to survive. There is no pressure to evolve via either of these methods.

But perhaps there is a new way for us to evolve, unforeseen by Darwin. Perhaps we are on the verge of deliberately engineering evolution for ourselves. Ongoing research into how attributes are passed on through our DNA are already enabling us to choose whether to give birth to a child with Down's syndrome, for example. We can even choose whether to continue with a pregnancy if the fetus is the wrong sex. There has been a lot of talk about 'designer babies'.

It would seem to be a good thing if we could ultimately remove inheritable defects from our genetic makeup on one level. But I have one name to give in answer to that: Stephen Hawking. If we start picking and choosing which individuals we allow to be born, how many unique, gifted, creative people will we miss out on?

For those among us who believe in the Creation, evolution has not occurred in the past so that our tinkering with our DNA is an affront to the Creator, and can only be asking for trouble.

Even without talking about God, we may well be playing with fire. For one thing, attributes, or groups of attributes, are linked to each other on a genetic level in ways we don't understand. In doing away with one, we don't know what else we are doing away with. For another, this line of research gives out the message that we are simply biological machines that do what our genes dictate. At best, this is merely offensive, at worst it might undermine our faith in our own ability to cope with life's struggles. Might we, in future, demand genetic engineering for ourselves to be made smarter, more beautiful, taller, etc, etc? Visions of Aldous Huxley's 'Brave New World' begin to creep in at this point.

The most frightening thing about this approach is that it could actually undermine our ability to adapt. Diversity is a prerequisite for adaptability. Our capacity for adaptation has made us the successful species that we are. It has stood us in good stead for 100,000 years.

Evolution has not been proved, but scientists carry on as if it has. If they are right, and our knowledge of it's mechanisms becomes more complete, there is every chance that we can take ourselves in hand and improve our species at a genetic level.

If they are wrong, and carry on working on current assumptions, it could be disastrous. We might already be on the way to self-inflicted evolutionary meltdown.

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More about this author: Briar Miller

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