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I am consistenly awestruck when I find out the multitude of ingenious ways in which organisms make the most complicated of problems at a cellular level seem trivial. With none is this more the case than the wonderful notion of "evolution", which not only is extremely elegant in its own design but allows everything to fall into place.
As a result I can get agitated quite easily when people dismiss the notion of natural selection and evolution without even considering it and admiring the extent to which is allows us to make some sense of a microscopic world of which we, in the end know relatively little about. However, it is also my opinion that the scientific community is very much lopsided in its opinion regarding a hypothesis that has not been proven as a fact at a fundamental level (to my knowledge anyway). And as much I endorse the ideas behind evolution, I can get easily irritated when people simply look down on others when they do not believe in evolution (Yes, I know I am a difficult person
). As I understand it, evolution has been "proven" as a fact regarding genetic change in organisms through generation, but it has NOT been "proven" with respect to the reasons as to why genetic change arises. I'll try and convey my thoughts on this and why I myself can't accept it as "fact".
The general reasons as to why variation arises seem to be the following:
- Combination of parental genomes
- Recombination
- Random mutation in germ line cells
Combination of parental genomes: This is not as much as a source of genetic variation as it is a way to randomly distribute the existing gene pool. I believe it can most certainly act as a means to propagate the "natural selection" of favourable traits, but I think that is a far cry from generating an eye from one generation to the next. And no, it does not make sense to start with part of an eye and then gain more and more bits of it through subsequent generation because accumulating "partial eyes" would challenge the very theory of natural selection that supposedly drives it.
Recombination: Shuffling DNA sequences may result in wonderful new DNA sequences, identical ones, different ones with same function or damaging ones. However, the truth remains that the chances of favourable change are extremely remote and the chances of damaging ones are orders of magnitude higher.
Perhaps a more intruiging point is that even though most organisms reproduce sexually and employ the above mechanisms, it seems to be an inferior form of reproduction when compared to parthenogenesis. Perhaps these processes do not have the exact functions that we thought them to possess. Recombination for instance has been considered a way for sexual organisms to bypass problems associated with Muller's ratchet. Parental recombination clearly functions much better to transfer naturally selectable traits than to actually form them.
Random mutations in germ cell lines: Notwithstanding the exhilarating notion of standing and admiring everything around me and being able to attribute it to randomness, it seems a little farfetched. It basically boils down to getting randomly mutated DNA becoming so incredibly beneficial that it will get selected over other mutations. Realistically I don't think this is very likely. Firstly the mutations in coding DNA are so rare and secondly, for every beneficial mutation, dozens of harmful ones will occur. The gene pool would be cluttered with damaging mutations and could not be selected against because then they would be selecting against the beneficial mutations too.
The biochemical world is full of anomalies that random mutation can not account for: gastrulation, endosymbiotic theory or even flagella suddenly appearing on bacteria at some point in history can not be explained by a couple of "lucky mutations". It seems to me, that the scientific community is overzealous to embrace an idea because it explains so much of what we see, feel, touch, hear and smell around us.
You might be thinking that I am just somebody who likes to criticise others without giving any alternatives myself. Well, I do have one, I think that genetic variation arises through regulated mutation, something along the lines of intragenerational selective gametogenesis. Anyway, I'm curious to hear what you think about this.
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