Evolution – a mathematical certainty

In the previous post, I mentioned evolution, and the reluctance of some to accept it, so I thought I should post my views on this, as a scientist, but one with no involvement in that area of science. I feel I can analyze information, but I have no personal involvement hence I have no position to defend. At first sight, evolution is a topic that causes more people not to think properly than any other. I disagree. I think evolution is simply a topic that attracts more attention. I think such faulty thinking is widespread, and this is partly the cause of the trouble that I think society is heading for.

One of the arguments against evolution is you do not see the intermediate stages. There are two answers to that. The first one is that we consider evolution over, say 400 million years. I do not know how many fossils we have, but according to Wikipedia the total number of known fossil species is less than 5% of all the currently living species, which means less that 1% of all species that have lived. If 99% of species have no fossils, it is hardly surprising that transitions between species are hard to find. The laying down of fossils is an unusual event. Most animals die and their remains simply rot away, or they get eaten, or digested by bacteria, or whatever. If some cause, such as a tar pit or a gigantic flood lets things fossilize, then what happens is you get a lot of fossils from that event. Furthermore, the argument is false because we do get intermediate stages. If we look at the evolution of the horse, there are fossil records from a small Echippus (about the size of a dog) to the modern horse. There are records of about 13 stages, so what more could you ask for? Then, of course, there is the dog. Do you think a chihuahua closely resembles the grey wolf? Check Wikipedia for the number of various dog breeds. These have all evolved. And what I find particularly disappointing is that after having this sort of thing pointed out, the anti-evolutionists refuse to acknowledge it.

Evolution is actually a requirement of simple logic. Either genes can mutate/change or they can not. If they cannot, all life is accurately reproduced, and Mendel’s cross-breeding of flowering peas simply would not work. Nor, for that matter could we ever breed sheep with the wool we see now, because wild sheep, while they have wool, it is very tiny and submerged below hair. If they can, then some variations give an advantage, such as faster running, or the ability to eat more things. Animals with an advantage are much better at capturing scarce resources, so at times of hardship, only those with an advantage survive, and at other times, they still prevail. Eventually, given enough changes in isolation, a new species will evolve.

In a recent edition of Nature, there was an interesting example of this sort of thing. About 11,000 years ago, mankind began farming cows for meat in Europe, the technique being introduced from the mid-east. Cow’s milk was indigestible because all adults at the time were lactose intolerant, which means that attempts to drink milk leads to extremely unpleasant fermentations in the stomach. Nevertheless, by about 7000 yrs ago the dairy industry was underway. We know that because some pottery residues have been found of objects that would be used to make cheese, specifically to separate curds from whey. If you make hard cheese, it has very little lactose in it, and cheese was a storable food, something to give protein and energy over the winter months. Some time later, a gene evolved that allowed those who possessed it to digest lactose. The net result appears to have been that those with it simply replaced those without it (of course breeding will have rapidly expanded to pool of those with it) for eventually most of those in Europe are lactose tolerant, while in many other parts of the world, they are not. A single genetic change such as that does not make a new species, and breeding will spread a desirable gene so that it becomes standard for that society. Suppose, however, we have two groups isolated from each other. Eventually, the accretion of sufficient changes in one group will lead to a species that can no longer breed with the other group, which has none of the first society’s changes, but presumably some different ones of its own. Our ancestors split from others similar to them at some stage when they left the forest and tried to make a living on the ground. Accordingly, we have evolved away from apes, but of course the apes have also evolved away from us, and as species, from each other. The concept is completely simple, and has absolutely nothing to do with religion.