Much Too Slow



Too Few Mutations- rarely favorable - inertia of populations


A second problem comes from the population genetics. This branch of biology studies how the characteristics in a population shifts, including through natural selection. It is a fairly mathematical science in which a good knowledge of statistics is important. Population geneticists have discovered the enormous inertia of evolution according to the proposed process of random mutations and natural selection; and also the extremely limited changes as observed.

Firstly, the mutation rate appears very low: thanks to an excellent built correction mechanism, is less than one mutation per genome per generation (about 10-10). Furthermore, mutations appear almost always harmful to the organism. So much so that one hardly knows beneficial mutations. Especially beneficial mutations that add information to the DNA appear virtually unknown.

Secondly, it is very likely that a beneficial mutation is lost in a population, and this by coincidence. In the production of a germ, after all, there is a 50% chance that a mutation is lost during cell division, and note: natural selection absolutely can not change this. This even shows a favorable mutation difficult to survive in a population. On the basis of the estimated "selective advantage" of a beneficial mutation (according to Fisher 0.1%) is the probability that a beneficial mutation survives in a population of about 1 in 500. This is called the "fixing" of a mutation, which of course is necessary, to count these mutations to evolution. Conclusion? Large populations can evolve statistically difficult.

However there are lots of mutations needed to account for all species on earth. An example may clarify this: human and chimpanzee are supposed to be about one million generations evolved to be apart. According to the findings of population genetics can produce at most, a few thousand cumulative mutations. Still, there are approximately 40 million necessary mutations to explain the difference in DNA, according to research in 2005. This is more than 10,000 times too slow. In many ways, scientists have made similar calculations, but the conclusion is always the same: too slow.


Slow

Some point to the relatively rapid 'microevolution' in artificial selection - with microevolution mean to limited evolution, usually the optimization of an existing structure, such as the length of tail or mouth. With 'macroevolution' is meant striking contrast and usually innovative changes such as the emergence of new limbs or senses. Macro-evolution, however, can not be done at the rate of micro-evolution.

Why not? An image can clarify this: a large population with much variation can be compared to a large reservoir full of water, the mutations can be compared with a dripping tap that reservoir slowly supplements. Now it is possible to create with the bucket of natural selection in a short time great changes from the reservoir, but the tap dripping of the mutations, of course, determines the long-term speed. All breeders moreover know that one can book  initially results through selection, but that no longer occurs further evolution after a while. Compare it to overfishing. And there is also a difference between the optimization of micro-evolution and innovation in macro-evolution, but we'll get back to this later. For now, we remember that the interplay of random mutations and natural selection is much too slow.