Been reading a lot on the evolutionist-creationist debate recently. Of course from the evolutionists’ point of view, coz that’s where my belief lies. One chapter I recently read was on how there were so many imperfections in the human body and how that was clear proof that man was not ‘designed’ by a higher intelligence but rather evolved from non-human ancestors. A number of examples are mentioned, not the least of which in the spine, never designed to remain upright. In fact even walking which we take in our stride (bad pun) is not a very smooth process. If looked at in detail with a fast motion camera and by studying the actual muscle motions involved, the human walk appears to be a series of ungainly motions, in fact it’s said that we actually fall from one step to the other. The examples are endless, truly. Our body architecture is just not designed to work as efficiently as possible. It’s merely a working model of ill-fitting parts that compromises here and there to make things work. It has been shown that if the optics of the eye were better, human vision would be in the range of 6/3, not 6/6. I could keep on pointing out such instances. The more I think about it, the more come to mind. I can’t possibly imagine what creationists have to say about all this, but I’m sure they’ll think of something, or they’ll just refuse to accept these as true. Whatever. But the chapter I was reading also gave examples from the animal kingdom of various ‘inefficient’ designs. One particular example was the marsupial Koala bear, whose baby pouch is upside down! Apparently the Koalas developed from a burrowing ancestor in which the turned around pouch served the purpose of keeping dirt out of the infant’s eyes and mouth as the mother dug. While explaining why the pouch had not turned right side up once the Koalas started climbing trees, the author (Dawkins) hypothesizes that the genetic change necessary to bring that about might be creating a lot of embryological turmoil, ultimately leading to non-viability of the foetus. He puts forward this theory in a number of places, for example the extraordinary course of the recurrent laryngeal nerve in the giraffe and so on. He postulates that the evolutionary benefit of changing the design to a more efficient pattern must be outweighed by the other deleterious effects that the same mutation, necessary for the beneficial effect, had on the embryo. On the face of it, it sounds plausible. Makes sense and it does explain a lot of odd things we see in anatomy. Even when we look at the cellular level and try to imagine what it would entail to change some embryological development pattern in the foetus, we can see that, for example, changing the sites of development of the kidney-ureter system and the testes-vas deferens system so that the vas doesn’t end up looping over the ureter and goes straight to the penis could only result from a profound change in foetal development. And every medical student how even small changes in embryonic development can have such disastrous consequences.
But it occurred to me that surely not every change for the better ( i.e. towards a more efficient body part) would necessarily require such major upheavals. Some changes like maybe the disappearance of the appendix in humans might not require whole scale alterations and some other changes might even bring with them other beneficial changes. Quite possible. After all the narrowing of our larynx is thought to be responsible for humans developing vocal communication which lay the groundwork for our social and cultural evolution. Maybe the change that brings about, say, the inverting of our retinas also makes our peripheral vision better by improving the acuity of the peri-macular retina. My point is that just because certain beneficial changes are not seen in our or any animal’s bodies doesn’t mean that change is improbable, or carries with it a baggage in terms of negative, deleterious effects. That is a very narrow Darwinian perspective of looking at random imperfections. One thing that everyone seems to have forgotten is the element of chance.
Maybe, the beneficial mutation to bring about the specific change has never happened. Darwinian Theory is based upon random mutations which get selected because they have something better to provide to the body that carries it. Granted. 100% correct in my view. But that doesn’t mean that all possible combinations of genetic code have been tried out. Maybe a mutation turning the koala baby-sac downside up is just around the corner. And maybe it has no other effect on the koala embryo, or maybe it even makes it better at climbing trees. After all, the way I see it, all mutations are a question of odds. When the DNA is being duplicated, there is a specific odds ratio that a mistake will occur. The odds may be high or low, depending on how stable that particular segment is. And the higher the odds, the less the chance of that particular change occurring. Let’s say for example’s sake, that the odds are 1 in a 1000 that a generation of Koalas would have one baby with the inverted pouch. Let’s say that the change would have no other effect on the Koala. All hypothetical, of course. I haven’t the faintest idea how such odds could be calculated, or in fact if they could be calculated at all. But assuming those odds, people think that in a thousand generations, the change would be brought about. And that’s where the fallacy lies. 1 in a 1000 are odds, not certainties. It’s just a chance that this particular change would appear in a thousand generations. But it might not. 1 in a 1000 doesn’t mean literally 1 in 1000, 2 in 2000 and so on. It might not even mean 100 in 100,000. These are just odds and might hold true at very large numbers or maybe not true at all. So what I mean is that chances are chances, not certainties and maybe the right mutation is right around the corner!