Evolution theory and teratology

What I mean by teratology very broadly is any discourse about freak babies or anomalous features in babies or birth deformities.An example of teratological phenomenon is a lady I know who is absolutely normal and even pretty, but in her small finger of the left hand there is a very small protruding finger like a twig from a branch of a tree.Are teratological features of offsprings the changes that are taken to be mutations, which will be naturally selected according to the circumstances of environment, so that after millions of years a different species will appear?I can speculate that the lady with that extra very small finger in the left hand small finger and all others like her, men and women, after millions of years will become a different species of homo sapiens or sub-species.What is the use of such a small extra finger?Why, in my part of the world we eat a small snail that is at most 3/4 inch in diameter and we have to use a thorn from the rose tree to pick out the organism inside to get to it and eat it.So such people with an extra small finger need no longer use a thorn from the rose tree, they can use their extra small finger and thus have one advantage over people without the extra small finger.If and When the only food available to mankind are those small snails, then they will definitely survive in the long run after millions of years while the rest of mankind without the extra small finger will become extinct.Anyway, tell me, knowledgeable people here, are teratological features facts of evolution as intended by the theorists of the evolution theory?Yrreg

Yes, those would be examples of mutations. Mutations come in three flavors: good, bad and neutral...and those terms are dependent on the environment the organism lives in. The same mutation could be advantageous in a wet environment but disadvantageous in a dry one.Whether a mutation is passed on depends on if that organism has a chance to breed. The mutations that are most likely to spark a new species are ones that offer up a significant reproductive advantage. A mutation that helps an organism survive longer than those without it, for instance, means that organism has more mating periods in which to pass its genes on.As for your lady friend, I assume she has every opportunity to reproduce. So now the question is whether the mutation that allowed her to grow another finger is a mutation that exists in her gametes. Human evolution is a tricky discussion because we are a lot less subject to our environment than we used to be. Rather than adapt to our environment, we adapt the environment to us. Groups of people will very rarely enter into reproductive isolation for the long amount of time it would require for a new species to arise.

This is a good question, although coffee house is not the right place for it, it's clearly a legitimate 'Biological Evolution' topic.The chances are that such a supernumerary finger could be the result of an environmental effect during development rather than the sort of heritable genetic mutation involved in evolution. I could be wrong, but you would need some familial history to find out.Having said that there are plenty of genetic mutations which are known to produce polydactyly in humans.In a situation such as you described with the snails then a genetic mutation leading to an additional small finger might well come to prevail, provided that there really was any sort of fitness advantage which I don't think your hypothetical example really shows.Even were the extra finger to become predominant I see no reason why it would lead to speciation in terms of two co-existing reproductively isolated populations, unless the people decided for themselves to practice segregation on the basis of finger number. Whatever the human race is like in a million years, in the unlikely event we make it that far, it would very likely constitute a distinct species to modern man, simply because of the genetic change which is bound to accrue over such a long period. Such a hypothesis cannot be supported however due to the impossibility of testing interfertility between populations separated by such large spans of time. In general no, in specific instances yes. But not 'facts of evolution' like an organism magically growing a new organ from nowhere but as in a fact regarding the role that genetic mutation has in producing phenotypic variation and a fact relevant to the role of the genes affected by the mutation on normal development and possible repercussions on our view of how that gene may have changed during evolution.TTFN,WK

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