How can mutations affect natural selection?

Answer 1

Mutations allow natural selection to occur. The mutation in a species that causes it to be the most fit will survive. the others die off. So, naturally, it is called survival of the fittest, the weak die off and the fit live on, passing their good traits to offspring. This is nature's way of perfecting a species. Mutations introduce new genetic information to an organism's genetic code

Answer 2

If a mutation causes a new trait to appear and that trait is favorable, then that organism lives to breed and it passes that trait on. If a mutation cause and unfavorable trait, that organism will die out.

Genetic mutation occurs when organisms reproduce, whether sexually or asexually. Therefore, over many generations, the frequencies at which traits occur within a population will slowly change.

Answer: Mutation was thought to affect evolution when it was postulated as a possible source of genetic variation to ennable natural selection to have material to work changes in organisms. This mechanism of variation was seen as vital to evolution from the time that the implications of genetics as discovered by Mendel was realised.

Unfortunately for evolution, there has never been discovered a single example of a mutation adding new genetic information (although occasionally mutations are beneficial, which is not always the same thing). Richard Dawkins was asked about this very issue in an interview and could not provide one single example of an information-adding mutation. This is no small problem for their is a staggering amount of new information necessary to be written into the DNA to change a microbe into a microbiologist (for example).

Actually mutations are universally shown to be causing genetic degradation in all multicellular life, In humans this is believed conservatively to amount to 100 new mutations per person per generation. Mostly these mutations are small such that natural selection does not 'see' them to eliminate them and so they accumulate in the genome of mankind like rust on a car. The rate of mutation which we observe today would lead to the extinction of the entire human race in a much shorter period of time than is commonly realised. This knowledge led one evolutionary geneticist to ask 'why are we not all dead already?'

According to geneticist Dr John Sandford, from Cornell University, there is close to unanimous agreement among geneticists regarding human genetic degradation, even though most continue to believe in evolution. Sandford cites recent papers by geneticists such as Muller, Noal, Kondrashov, Nachmann/Crowell, Walker/Keightley, Crow, Lynch et al, Howell, Loewe and Sandford himself (in print). Sandford highlights Loewe's contention in a paper published in 2010 (in The Proceedings of the National Academy of Science) that there is a fitness decline of between 3-5% per generation. Sandford himself from his modeling believes it is not as dire. Another geneticist, Robert Carter, points out that the key issue is not that there are no beneficial mutations but that the deleterious ones are so subtle that they are not selected against, and so the net effect is downhill.