It is normally held that evolution is driven by beneficial mutations.
There are some basic facts about mutation though, which we should keep in mind:
- Mutations are extremely rare. A 2002 study about mutation rates in mammals “that the average mammalian genome mutation rate is 2.2 x 10(-9) per base pair per year”.
- They are always completely random, which further increases the time of anything useful turning up.
- Even worse, not much useful will ever turn up, since essentially all mutations are harmful and sometimes even deadly, with very little exceptions.
- Although there are rarely some mutations (or more accurately, combinations of already existing traits) which are beneficial, they have drawbacks. For example, antibiotics-resistant bacteria are weaker than normal ones and so are less likely to survive when there are no antibiotics present.
- Mutations never make a new kind of living organism, because lots and lots of interrelated mutations would have to occur, and the more mutations occur, the more likely it is that the harmful ones kill the organism. Besides, no one has ever observed such a process.
The fruit fly experiments
In genetic research, the fruit fly species known as Drosophila melanogaster has been investigated extensively. That is because this animal has only 4 chromosomes and reaches maturity in one week, so lots of generations can be studied and its genetics isn’t as complicated as that of many other animals. In 1927, the American scientist Hermann Joseph Muller, while experimenting with fruit flies, discovered that X-rays cause a higher rate of mutation. Since, then there have been a lot of experiments trying to cause mutations in fruit flies and observing their effects. The experiments have comprised of hundreds of fruit fly generations.
Mutations include neutral ones like yellow-colored and ebony-colored flies and harmful ones like curly-winged flies, which cant’ fly properly; short-winged flies, which can’t fly at all; eyeless flies; and flies with leg-like antennae.
These fruit fly experiments yield two important conclusions:
- Fruit flies are still fruit flies. They haven’t changed into a different kind of animal, so there has been no evidence of evolution.
- Mutated fruit flies are not better off than normal fruit flies. A 2010-study entitled “Genome-wide analysis of a long-term evolution experiment with Drosophila” in “Nature” did try to show a beneficial mutation, namely one where the time until hatching is reduced, however that mutation didn’t take hold in the population, since “unconditionally advantageous alleles rarely arise, are associated with small net fitness gains or cannot fix because selection coefficients change over time.” (quoted here) That latter part means that “it is very difficult for even a helpful mutation, which is rare, to take hold in a population because, by the time the advantage in the environment is felt, the conditions change to make the helpful mutation, which was a loss of information anyway, not so helpful anymore”. (here)
Antibiotics-resistant bacteria
Another note on antibiotics-resistant bacteria: a 2011-study in “Nature” entitled “Antibiotic resistance is ancient”, as well as some other studies suggest that antibiotics-resistance is much older than antibiotics. This study analyzed bacteria samples taken from permafrost in Beringia, and found that “a highly diverse collection of genes encoding resistance to β-lactam, tetracycline and glycopeptide antibiotics”. Mutations causing antibiotics-resistance are occurring naturally.
As Vance Ferrell, author of the “Evolution Disproved” book trilogy, “[t]rying to accomplish evolution with random, accidental, harmful mutations is like trying to improve a television set by throwing rocks at it.” (Vance Ferrell, Evolution Disproved Series – Book Two, page 399)