I was reading an article in New Scientist yesterday about evolution. It concerned a type of finch, which after domestication had evolved many traits that its wild counterpart did not. The article discussed how a domesticated animal, apparently free from the pressures of natural selection, would not just continue to evolve, but evolve at a very fast pace. The basic theory is as follows:
Typically natural selection places very tight ‘controls’ over the evolutionary process, paying short thrift to any traits that appear that are of no benefit to the species. Therefore, only those traits or mutations that are of any benefit stay with the species.
Thus, any mutations that appear that are of no real benefit quickly disappear.
Going back to the finch, the wild species has a very mundane, monotone call used to attract mates. Its domesticated counterpart has wide-ranging, melodic calls, vastly different to the wild. The reason for this, based on the assumption mentioned above, comes down to the lack of evolutionary pressures on the domesticated finch. Mutations appeared in terms of vocal range, and as the pressures of natural selection have been ‘eased’ as it where, these mutations have stayed on, and subsequently increased.
In the wild population, the efficiency of natural selection would dictate that mutations in bird calls not only would be of no benefit, but would actually be detrimental. A male finch born with a mutated bird call would have more difficulty in finding a mate; therefore this trait would very quickly disappear, perhaps lasting less than a generation.
In the domesticated finch, the mutation has a completely neutral result, so therefore 'relaxed' natural selection will allow it to stay.
The same theory has been put forward to explain the complexity of our own species. Simply put, as we have progressed, or evolved, many of the pressures of natural selection have been eased. For example, as we refined our hunter-gatherer techniques, and there was less pressure on finding food, we had mental capacity left over for the development of such things as language.
As we have evolved and developed, we have become better and more efficient at doing things. Agriculture and animal domestication made life easier by taking the pressure off finding food. The development of civilisation and societies made life easier all round in terms of survival.
Think of it like this: earlier on, all our mental capacity was taken up just trying to survive one day to the next. As we developed, and became more efficient in our day-to-day existence, less of our mental capacity was required for daily survival, so we therefore had spare capacity that could ‘evolve’ other traits that ordinarily wouldn't be allowed under 'tight' natural selection, such as language and religion (definitely not one of our better moments, to be sure. Obviously, this ‘spare capacity’ didn’t always lead to good things).
So if we stick with this theory, it really does make you wonder how far we as humans will develop. Our lives are getting easier and easier as technology develops. We no longer have to utilise much of our mental capacity for survival, which perhaps explains why we have seen such amazing advancements in human thought in recent times. Based on this theory, it would perhaps be reasonable to hypothesize that out intelligence will continue to grow exponentially, the pace of growth ever increasing as we utilize more and more of our capacity.
But i don't think we will. The whole premise of the theory I read about was the notion of 'relaxed' natural selection. The strict rules no longer apply, so traits that ordinarily would not be allowed to reproduce do. Obviously, this is a two way street, and something this particular article didn't explore.
If we assume that certain non-useful traits stay in an environment of relaxed natural selection (for example, bird songs in domesticated finches), then it must also be assumed that certain negative traits will also stay and multiply within a population. And I believe this is what is happening to us.
I believe that natural selection has been relaxed so much for Homo Sapiens that it no longer applies. It could therefore be argued that we are in effect in a state of 'devolution'. Let me explain:
Natural selection and evolution is such that negative traits are not permitted to stay on in a population. If a mutation leads to negative consequences, the mutated individual will have a hard time breeding and thus passing on the negative trait. Likewise, if an individual is born with a mutation that gives it an advantage over other individuals, this mutation is likely to stay and be passed on to future generations. Now, this is a very simplistic way of explaining the process of natural selection, but hopefully you get the idea (for a much more eloquent and thorough explanation, I would recommend Climbing Mount Improbable by Richard Dawkins).
Obviously, these rules no longer apply to us. Through advancements in medicine and health care, traits that would ordinarily breed out of a population not only stay, but multiply. Hereditary conditions illustrate this point. If we take a condition such as cystic fibrosis, modern medicine now means that many people not only live much longer, but also produce offspring. As the disease is hereditary, it is being passed on to future generations. Obviously, as time and medicine progress, more and more individuals will be born with this particular defect. And so on it goes for many more conditions.
So, as a species we are getting sicker and sicker. If the rules of natural selection still applied, an individual with cystic fibrosis would most likely die at a very young age, and hence would be unable to pass on the defect to a new generation. Eventually, the genetic mutation or defect would be bred out of the population.
As a species, we have reached such a pinnacle of advancement that we have effectively 'switched off' one of the most fundamental laws of nature.
I do believe though that it's not all doom and gloom. While we are getting more 'defective' in the short term, I believe that eventually our ceaseless advancement will reach the point where we can artificially remove negative traits. Researchers are already searching for the defects in our genes that lead to many common illnesses and impairments. The day were effective gene therapy can remove such defects as cystic fibrosis is perhaps not too far away.
Once this happens, we will enter a phase of artificial natural selection. We will turn the process back on, but we will be in control, not nature. I personally find this to be a very scary thought indeed. Who will ultimately decide what's defective and what isn't?
We can already test fetuses for defects such as down syndrome. What happens when science finds the 'gay' gene? Will parents be able to test for that as well? Where will it stop?
Obviously, being able to detect defects early is of enormous benefit. The problem lies in defining exactly what a 'defect' is. The less enlightened of us would consider homosexuality as a defect. Should parents have the freedom to test for and then treat (when science is able) a perceived defect such as this? If not, then who will ultimately decide what can and cannot be treated? Clearly, there are many traits that more rational people see as just that- traits. Some, however, will see many traits as defects. The white supremacist who sees anything other than blonde hair and blue eyes as defects. The ignorant red-neck who views homosexuality as a defect. Should they be able to screen and treat what they perceive as a defect? Obviously, I would say no, but then why do I get to decide?
I guess this is the problem when we take over control from nature. Nature is ethical, and operates natural selection with no ignorance or bias. Once you introduce free thinking to the process, massive flaws start to creep in. The problem, of course, is that free thinking is not entirely free. We may think of ourselves as free thinkers, but the way in which we think is very heavily influenced by our culture, our upbringing and many other factors, many subconscious.
If free thinking were truly free, then a future where we control natural selection may not be such a scary place. As this will never happen, I can only look forward to the future with a certain sense of foreboding and apprehension at what we may become.
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