Many theists don’t understand that mutation happens every day… All organisms are constantly exposed to mutagenic rays and chemicals and are always undergoing cell division.
There’s literally no escape. If you hid alone in a dark cave for all of your life, you would still experience mutation. It might be speeded up by the radon gas invisibly emanating from the rock surrounding the cave, but it will be happening anyway due to inaccuracies in the process of your own growth or tissue replacement.
First it is necessary to understand that a body is always changing. In the early stages of life an organism develops. The one fertilized egg that we all begin as, divides into more cells which grow and divide again. That requires the recipe for the individual, which is in the form of DNA, to be copied into each extra nucleus. This is a complicated process, called Mitosis, in which the microscopic, threadlike chromosomes undergo a ‘dance’. They get tangled up, replicate and separate into two new nuclei. Unsurprisingly, given the delicate nature of the structures, sometimes chromosomes get broken and swap parts or lose bits. That alters the message. That’s mutation.
Then it is necessary to understand that Mitosis doesn’t just happen in growing juveniles. All of our organs are constantly being replaced throughout the whole of life. Think of blood as like engine oil: it deteriorates and needs changing. In the case of blood, the refreshment is going on constantly so the blood you have circulating through your vessels today is entirely new compared to the blood you had three months ago. Even bones, which may look like rock but which actually contain cells, are always recycling – the skeleton you have now is not the same old one you had a few years back. Without this happening, broken bones would never repair.
So, if you have understood the above two paragraphs, you will see that, given the massive amount of cell division that is going on constantly, some transcription differences will appear in the messages. Unfortunately, some of these mutations cause the condition that we call ‘cancer’. It can happen at any age but, naturally, the chance increases as the alterations to the DNA accumulate over time. If you live long enough, you will likely get cancer. That’s mutation.
Have I needed to mention ‘evolution’ yet?
Now we need to talk about a different form of cell division: Meiosis. This only happens in the sex organs: the testes and ovaries. It is different from Mitosis because, during this process, the instructions are halved. All of our body cells have two copies of the human recipe book but our eggs and sperms must only have one copy each because they have to meet up with another edition from a sexual partner and that’s when the doubleness is restored: at fertilization. During this Meiotic division, when the chromosome number is halved, alterations to the code occur just as they do in Mitosis. That’s mutation.
This is the only occasion when mutation could possibly have an impact on evolution, because it could help to determine the characteristics of a single offspring. But it’s not the only influencer and probably not the main one. There is another cause of the unique characteristics exhibited by an offspring due to the novel mixture of genes from the two parents that came together at fertilization. If you notice a child has your eyes but your partner’s hair, that’s probably due to unmutated family traits being passed down in a new combination.
And, don’t forget, each egg or sperm comes to nothing unless it is involved in a fertilization event. A organism needs to survive and reach sexual maturity in order to breed and then it generates a vast number of gametes that won’t ever be involved in producing young. Those sex cells contribute nothing to evolution, whether mutated or not. Similarly, all the mutations that a juvenile experiences before engaging in sexual activity, or an adult experiences after they have finished breeding, have no effect on evolution. Mutation is hardly any more connected to evolution than breathing is.
Isn’t it obvious that by far the biggest ‘job’ that mutation does is to cause cancers that are sometimes benign and sometimes malignant?
Besides all of which, evolution doesn’t act on single individuals, it acts on populations. Mutation just happens to provide some, but not all, of the variety of organisms that can be sorted by the environment into breeders and non-breeders.
Do you begin to see why mutation is not the driving force behind evolution? It’s just a passive source of some variation.
So, mutation is not only associated with actively producing the next generation, nor is it the cause of the new ‘hands of cards’ dealt out at fertilization. Therefore, it cannot be described as the primary mechanism that has brought about the diversity of life. It’s just partially responsible for some of the differences in a population. The enviroment acts on those differences in a process called Natural Selection.
NATURAL SELECTION IS THE MECHANISM OF EVOLUTION.
By the way, Darwin knew nothing of the above…
We’ve discovered all that since he died, but, guess what?
It is all consistent with his Theory of Evolution!