Have you ever heard of the peppered moth? God has created many living things, some amazingly powerful, others wonderfully complex and intricate. The peppered moth is not particularly remarkable in any of these ways; it does not stand out among God’s creatures; so possibly you have not heard of it. Yet many people who believe in evolution love the peppered moth because they think that it shows evolution in action. In many Biology text books you can see photos of peppered moths and a brief outline of an experiment carried out by Bernard Kettlewell in the 1950s. The peppered moth story can be summarised as follows.
There are two varieties of the moth: light and dark. In areas with a lot of industrial pollution, the lichen growing on the trees died, leaving sootdarkened tree trunks. This meant that the dark-coloured moths were better camouflaged and the light-coloured moths made easy prey for hungry birds. So, over time, the number of dark moths increased and the light moths decreased. However, when the environment was cleaned up and the lichen started growing again on the trees, the number of light-coloured moths began to rise again and the number of dark coloured moths became smaller.
Kettlewell felt that his observations of the moths were evidence of the idea that organisms can adapt to suit the environment they are in. He and his evolution-believing colleagues concluded that, if this process of adaptation continued for long enough, a new species could possibly evolve.
Although the methods used in the experiment have been severely criticised, we can agree with the first part of Kettlewell’s conclusions. Living creatures can adapt to their environment. The type of organism most suited to the environment will live longer and have more offspring, passing their genes on to the next generation. This is the “survival of the fittest”. The scientific term for it is natural selection.
Think of animals in the cold climate near the North Pole. Animals with thick hair will be more likely to survive than animals with short hair. Animals with white fur will also survive quite well as they will be camouflaged against the white landscape; they will be able to avoid attack by hiding, and will themselves be better able to catch other creatures. So the animals which will be the “fittest” in this environment will have thick, white hair. They are likely to have more offspring which will also have thick, white hair because the genes from the parents, coding for thick hair and white colouring, will be passed on to the offspring.
Natural selection was first outlined as a theory by Edward Blythe, a Christian scientist, a quarter of a century before Darwin put forward his ideas about the origin of species in 1859. But why should people who believe in evolution take such a deep interest in natural selection?
Evolutionists use the scientific fact of natural selection as a way of trying to explain how evolution might occur. As one Biology textbook puts it: “Natural selection, among other processes, contributes to the evolution of new species and . . . the great variety of living organisms on the Earth is the product of millions of years of evolution, involving natural selection”. They argue that, if these changes within populations of organisms are allowed to go on long enough, they will result in permanent changes. Therefore, they claim, evolution will have taken place as new species of organisms form. Some evolutionists go so far as to say that natural selection is actually evolution in action.
For simple organisms to evolve into more complex ones you would need new genetic information. The changing proportions of dark and light moths do not involve new genetic information, only changes in the prominence of one gene over another. Indeed, if natural selection goes on for a long time the result could be loss of genetic information. This will happen if the characteristics certain genes code for are eventually lost. For example, if the pollution continued, light coloured moths might have become extinct and so the genetic information for coding for light colour would be lost. In some cases this can lead to a new species being formed, but this species would be a sub-species of the original one as it would have less genetic information.
Some of the details of Kettlewell’s peppered moth research have been challenged. However, if we consider it in the best possible light, we can on this occasion agree with a biologist who believes in evolution, who conceded that it merely shows natural selection, but not “evolution in action”. In spite of this, the peppered moth is presented repeatedly in textbooks as evidence of evolution in action.
God created plants, animals, birds and all sea creatures “after their kind” (Genesis 1). In His infinite wisdom He created them with enough genetic information to diversify and adapt to the different conditions they would find themselves in. He alone deserves the praise for creating and sustaining all things. Psalm 104 helps put everything in perspective for us:
“How manifold, Lord, are Thy works!
In wisdom wonderful
Thou every one of them hast made;
earth’s of Thy riches full.”
S M Campbell
[This article was the fourth in a series entitled “How did it All Begin?” originally published in The Young People’s Magazine. This article appeared in the January 2006 issue. For the previous article in the series, see Our Seven Day Week.]