Mutation Rates

I think that mutation rates evolve within the species. As a species advances and develops, many mutations will be more harmful than helpful to the individual. In the context of Darwin's 5 postulates, mutations would increase individual variation which would lead to differential survival. If one mutations helped an individual, then it would be able to survive and reproduce better than those without the mutation. For the most part, mutations will increase or decrease fitness and would lead to differences in generations on an individual level. Helpful mutations will be passed on at a higher rate than those that are detrimental to the organism's health. Additionally, smaller organisms with a higher reproductive rate will likely show a higher mutation rate in the same period time than that of a larger organism. Reproducing will lead to more mutations within the species, and an example of this is what is seen in bacteria.

In humans, a low mutation rate might be more adaptive than it would be in bacteria, for example. Bacteria generally benefit from a high mutation rate since their existence is threatened almost constantly. Humans use many chemicals and substance to kill bacteria, which can range from hand sanitizer to antibiotics. In order for these bacteria to survive and reproduce, they must mutate in order to fight back against these substances, also known as antibiotic resistance. One thing that doctors like to emphasize is to take the antibiotics that they give you as they are prescribed. If a human is fighting off a bacterial infection, the antibiotics will be able to kill just about all bacteria if taken as directed. However, if the patient forgets to take it for a couple days or stops halfway through, there will be bacteria left over that have been exposed to this antibiotic, but not killed by it and have the chance to mutate to survive. These bacteria will mutate and become resistant to the antibiotics, which will benefit the bacteria in its ability to survive. On the other hand, humans may not need such a high mutation rate, since many of these mutations would be detrimental to health and function.