Natural selection
Ed. note: long after this article was written, it was shown that many of the peppered moth photographs were faked—see Goodbye, peppered moths.
Picture books and museum exhibits often show changes in living things, for example differing beak types in finches, changing physical forms in dogs, and changes in the colour of moths. These pictures and exhibits claim to show how evolution works through the process of natural selection. In more advanced textbooks natural selection is claimed to produce a change in the ratio of the genes or a change in gene frequency and this in itself is called evolution.
But both of these claims about natural selection are easily demonstrated to be false by the following interesting experiments which you can do in your own home or classroom.
Evolution
Evolution is the proposed process by which living things gain entirely new characteristics that were never before present in their genetic make-up, not even in a latent or ‘hidden’ form.
Natural selection is simply the effect the natural world has on living things, selecting out living forms that can survive from those that can’t handle their environment and therefore perish. All too often we see the results of natural selection being claimed as evidence of ‘evolution’ in action. Such a conclusion is either a bad case of ‘jumping to premature conclusions’, or shows a poor understanding of what ‘evolution’ really is. Evolution and natural selection are two entirely different things.
The following simple and easy-to-do experiment will show what that difference is. It can be performed with a large stack of miscellaneous clothes buttons and some builder’s sieves of different mesh sizes.
Sieving the buttons through the mesh, mimics the action of natural selection—sorting out which objects will survive the testing process. The use of different mesh sizes will sort out the buttons quite differently (this is analogous to different environmental conditions or selection pressures). Buttons that survive one sieving may be caught out in the next.
What we have at the end of the sieving or selecting process are groups of buttons of similar size, each of which will be quite different from the original collection of all shapes and sizes thrown in together. No button has changed, but what if some buttons did not make it right through the sieving process? If all the buttons which stuck on the first sieve were thrown into the fire and burnt, you could claim they had become extinct. That is what natural selection does—it can eliminate species. Likewise from our button experiment, it would be extremely naive to claim that the button populations (the groups of buttons) had ‘evolved’ since all the buttons were present right at the start—no new types of buttons had appeared from the beginning. If you wanted new buttons to appear on the scene, only the supplier of the buttons could introduce new kinds of buttons. However, note that each pile of buttons you have from your sieving will be a new combination, a previously unseen combination of those things that already existed at the start.
This is exactly what results from natural selection. Natural selection produces or uncovers previously unseen combinations of genes that have always been there and remain unchanged. When new drugs have been tried out on germs it has usually been discovered that the germs that survive the drug were already resistant not because they were evolving resistance, but because they already possessed it. Those that didn’t possess in-built resistance became extinct. They couldn’t get through the mesh or sieve of the new selection pressure of the drug. Those that did survive were the ones that went on to make obvious a previously unobserved combination of existing genes that were already present. The population hadn’t changed or evolved. One section of it which was previously unknown or was a minority had now become the majority.
Natural Selection and Gene Frequency
In many advanced textbooks about evolution it is often claimed that evolution is a change in the frequency of the genes. But this simply is fallacious. If evolution were true it certainly would produce a change in the ratio of the types of genes which were present, because it would be adding new genetic information which previously did not exist. But the converse of this is not necessarily true. You can change the gene frequency or the ratio of the genes that are already present as much as you like, but unless you add new genes you won’t get evolution.
In evolutionary textbooks it is common to see the two forms of the English peppered moth (Biston betularia) being used as a ‘proof’ of evolution at work. There are two forms of this moth. One is jet black, the other (more common) has a sooty or peppered colour scheme. Soot-covered trees during Britain’s industrial past were an excellent camouflage for the black variety, whereas the peppered form stuck out like the proverbial wart on a prune and was easily picked off by the birds. Hence, for a time the black form of the moth was favoured. Its population increased, while the number of peppered individuals waned. The effects of the gene for blackness were favourable to the moth and thus moths whose genes expressed the black colour were seen much more commonly—the effect of the black genes was seen more frequently. This means that the number of genes for blackness began to increase and the number of genes for peppered colour began to reduce. Obviously, the ratio of genes was changing. But there were no new genes. There were black and peppered genes at the start, and black and peppered genes at the end.
Another simple experiment will help clarify the point that changing the gene frequency is not the same as producing evolution.
Obtain multiple copies of the back page of both an early and a late edition of an evening newspaper. These pages of information represent the genetic information in the two forms of peppered moth. The information printed on both versions of the back page will be very similar. Probably only the stop press and one or two minor items will be altered, but this is enough to make them two different and unique sets of information.
If we now make multiple copies of the late edition’s back page but keep only the original single copy of the early edition’s back page, we have increased the frequency of the later edition’s information. Note carefully that we have done nothing whatsoever to alter the total amount of unique information. It would not matter if we made a million copies of both editions of the back page; we would still have only two pages of unique information. The multiple copies are merely that-mere copies, mimics. They do not add any new information. To obtain increased information (rather than just an increase in the frequency of existing information) is far more complicated. It would entail journalists researching a new story, layout people formating it up, so as to yield a unique back page full of new information. You could not get new information without intelligent design.
Evolution, if it were to occur, would require the creation of completely new genetic information. Changes in living things, such as the colour distribution of the peppered moths, show an interesting alteration in colour-gene frequency, but they offer nothing at all to support the notion of evolution (that is formation of new genetic information).
Conclusion
Natural selection certainly can produce changes in gene frequency, but neither natural selection nor any changes in gene frequency will automatically produce evolution. They most certainly have not been observed doing so.
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