A week or two ago Nature published a report about how chickens developed a beak from the flat snout of their dinosaur ancestors. All that was required was a change in position of two proteins. Evolution.
We have recently been discussing evolution and, no doubt, we will do so again. So this week I am providing a simple account of this. Many of you will already know the facts, but I think our discussion may well be improved by us all starting from a common, base, position.
In the 19th century biologists began to question whether there was some mechanism which brought about the differentiation of the various species. Darwin and Wallace came up with the solution of evolution – which Herbert Spencer described as “the survival of the fittest.” This was hugely controversial in a society where the description of creation in Genesis was common ground. It remains so today, and we see this in pinprick attacks on aspects of evolutionary development, or in the insistence that evolution is no more than a theory – with the unspoken subtext that it is just a provisional idea.
In fact evolution itself is not a theory, it is an observed phenomenon, supported by massive evidence. And this is not surprising since it is a necessary procedure for biological entities which pass on their characteristics when they reproduce. Darwin knew that offspring carried the characteristics of both parents but he did not fully understand the process. It was several years before the work of Mendel, an Augustinian friar, opened the way to understanding the work of genes.
The principle may be easily explained by a simple example. Imagine an early ancestor of the dog. In such a population there will be a few who, by chance mutations, have a better sense of smell than the others. These ‘superdogs’ would have better access to food than their fellows, so they would be more likely to breed. This might have been aided by their greater ability to identify bitches on heat. Over successive generations the proportion of ‘superdogs’ would have risen. Thus the modern dog has a sense of smell many times higher than that of humans.
Because evolution involves an interplay with the environment, we would expect changing environments to play their part too. Why are Inuits short and stubby? Because the thickset retain body heat, enabling survival in a cold environment. Why are the Masai tall and slim? Not hard to work that out either.
Evolution is continuous. We are rarely aware of this because the timescale is usually much longer than ours. But there are examples which can tracked. A classic is the peppered moth. Before the Industrial Revolution the light-coloured moths were camouflaged against the light-coloured trees, while the dark-coloured were an easy prey for birds. But as the tree trunks blackened through industrial pollution, the advantage switched to the dark-coloured version. And, with successive generations, the proportion of black moths increased greatly, at the expense of their lighter cousins.
So no educated person will deny that evolution brings about the development of different characteristics and different species. Yet there are still many instances where it has been difficult to track how the necessary changes came about. So is it possible that there are other systems or procedures which are active, too?
At the scientific level the answer is ‘no’. Science cannot prove negatives so, in theory, its conclusion can only be provisional. However, all the evidence points in the direction of evolution. And no evidence of substance points any other way. To claim that the general principles and procedures of evolution are in doubt is simply gratuitous.
The only objection to evolution which still carries weight is a primitive religious position which claims that we must take the biblical account of creation as a literal description. The big New Catholic Commentary on Holy Scripture suggests that such a view requires either bad science or bad exegesis. We have seen the Church move from criticism to tolerance to a general acceptance that the Bible and science are not at odds.
But we too may have some psychological concerns. Evolution has no agenda beyond survival in an environment. It would almost seem as if God had washed his hands of the detail, and left the rest to chance. But what we call chance is in fact the result of ignorance. We call the fall of a die chance simply because we do not know the effect of all the factors. God does. The advantage of omniscience is being omniscient. We may think evolution to be extremely complex; how much easier it would be for God to bring about all the universe with a single fiat. In a computer age we should more readily understand how a simple equation can bring about complex change. Evolution is God’s simple equation, and he used it to people the earth. Far from deploring it, we should be lost in admiration at its elegance.