Are we, as a species, evolving slower now we've essentially eliminated natural selection? Survival of the fittest is no longer an issue, as we've all seen on the Jeremy Kyle show. Or are we evolving faster due to our own meddling in biology, medicine etc?
Evolution
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yes, in the past 100 or so years we've slowed down a process that takes millenia. We've neither slowed it down, or sped it up, we have adapted to our surroundings, our ability to manipulate things to enable us to do this is something that we have evolved and will continue to evolve.
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Personally I think since we've almost eliminated the process of natural selection we're becoming a weaker race. Society can support the weak through medicine and help and the weak are able to reproduce and pass on their weak genes. In the past the blind and people with hereditary diseases would have largely not been able to pass on to another generation and society grew physically stronger as a result, with fewer defects.
It's an odd view, I know.
It's an odd view, I know.
But at the same time, we're creating new cures and preventing these "weaknesses"
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But you could also say that we have become stronger because we have adapted to use computers and technology. Did cave men become weaker because they invented fire or tools?
*Edit*
I do think that evolution as a process takes so long to view that our scientific meddling may do nothing long term.
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Soldato
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Nitefly's gonna cry when he reads this...
It is also quite a badly flawed view too. As most hereditary diseases didn't stop people reproducing they have been around for quite a long time already so they aren't a serious flaw as far as passing on your genetics. If you also look at the point of evolution as being able to survive long enough to pass on your genetic code then those "weak" people are the ones having more kids so are in fact "succeeding" on a genetic level more than those that don't have kids. In the past people with hereditary diseases did in fact manage to pass them on to another generation, hence they are hereditary...
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We adapted to our environment or perhaps it is more correct to say that we've created adaptations to allow us to exist more comfortably in our environment. Whether that's a positive or not will rather depend on what metric you choose to take to measure success - as a species we're arguably less hardy and less virile than we used to be but such issues have been broadly overcome in many regards so we're now more populous than at any point in history.
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Soldato
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i'd agree with that
In all honesty, it wasn't as bad as I had feared
Your question is an odd one as it is based on rather narrow and unrealistic definitions of what some of the words you use mean. I will explain the problems with some of your definitions, then I give my opinion on what I think you are asking
Firstly, you speak of 'evolving slower and faster'. This doesn't really make much sense as evolution should be viewed as the passing of genes between generations of a population. It cannot be 'faster' or 'slower', it has no fixed end point of what it is trying to achieve.
Also, 'survival of the fittest' is a phrase that is utterly meaningless if you want to apply it to any realistic scenario. It is a wafer thin sound bite that has no substance - it certainly isn't a phrase that is used in any scientific discussion.
I believe what you are actually asking is 'are we reaching increased and "desirable" complexity at a slower pace due to our social structure and technology?'
Secondly, you speak of evolution being 'slower' as we have 'eliminated natural selection'. A very important point to note is that evolution is much more than natural selection. Most people are unaware of sexual selection - we are not here simply to live, but to reproduce. Evolution towards and away from desirable attributes (for example, tall / small height, large / small breasts, blonde / ginger hair colour etc) still occurs in all human populations today. So in this respect, there is selection on our population in the same way as there is in other animals.
What you are of course referring to is the lack of selective pressures for viability selection, or in other words, the lack of external factors than might influence our species to become superior in physiology (increased strength, improved vision etc). In comparison to former generations, this is certainly true. Most obviously, we are at less risk from disease. Less obviously, men are no longer required to have good eyesight for hunting or other activities. What has happened is that the genes which correlate to relatively good eyesight are now subject to something called 'genetic drift'.
This means it doesn't matter if your genes are the alleles (specific varieties of genes that code for a specific function) that confer the most desirable phenotype (physical or physiological attribute - such as hair colour) - the abundance of those 'desirable' alleles will slowly decrease in the population by random chance.
So we might expect that eye sight has decreased in quality since modern civilisation came about. That is a potentially naive viewpoint. Eyesight is not the only attribute that confers to physical ability - providing eyesight is above a certain threshold, it is dubious as to whether it might confer a massive advantage in the light of the millions of other attributes that might pose a similar advantage to physical ability. All we know is that the selective pressure for good eyesight (with this pressure arguably being quite weak once eyesight has passed a certain threshold of quality) has been removed.
We also know that those genes have been subject to genetic drift for several thousand years. Is that really such a long time for genetic drift to act to the detriment of good eyesight? It is pretty difficult to conclude one way or the other.
I would also say the idea that medicine has removed the selective pressures for increased viability selection is a partial red herring. Parasites, bacteria, viruses and other pathogens are adapted to attack the most common genotype within a population. Thus, to some extents, you will stand a better chance of survival by being away from the norm in your genetic make up. Remember, humans have an adaptive immune system, so that your immunity to certain diseases will not be passed onto your children. There is the occurrence of genetic resistance in populations where disease is prevalent (such as genetic immunity to yellow fever), but it doesn't appear to be true for most common illnesses. This is all said of course knowing full well that hospitals do save numerous lives of the young and the old, but again this not necessarily to our detriment. Say a 2 year old child has a deadly disease yet has the aforementioned genes for good eyesight in combination with other desirable genes. Is it a bad thing that his 'weak genotype' is allowed to persist? Just because you vulnerable to a particular disease for whatever reason does not mean your genetic make up on the whole is undesirable.
So in summary, all we can say is that some selective pressures have been removed due to modern society. That is not to say that we have become weak, although it does lead us to rightly question if some aspects of our physiology are declining in quality - the answers are not obvious. One thing is sure though - evolution has not stopped in modern human populations, not by a long shot.
I hope that has provided some food for thought
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Interesting points, interesting reading. I was also going to add to that the quality of society and the effects of mass breeding of the lower intelligent classes but King85 beat me to it...
I really ought to see this film one day. It's supposed to be greatJust watch Idiocracy i'm pretty sure it hits all the key points
Soldato
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Just watch Idiocracy i'm pretty sure it hits all the key points
great film! watched it countless times since i got it
On a slight tangent, something my girlfriend always points out is that evolution has no direction as such. Its just random mutations that may or may not provide an advantage to a species. We're not striving for perfection, and it will never stop naturally.
Broken.
Broken.
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That's not true. Mutations are random, selection is distinctly non-random. Evolution is thus not a random process at all with the exception of genetic drift, and selection will create a preferable variety of alleles relating to a phenotype in a population - thus it is possible to say that evolution will have direction, whether it is stabilising selection or otherwise.
It's a completely biologically ignorant view. Evolution has never favoured the "strong" over the "weak"; it just doesn't work like that. What it does is favour those who are most fit in the current environment. There is nothing we can do to change that.