Mueller's ratchet. Ahh, yes. Within most asexually reproducing species the buildup of diliterious genes will, eventually crash the population, even to extinction. Some corollaries in small inbred sexual populations as well...like Arkansas.
May I make one observation? Picky, I know, but do let's keep things straight.
"Evolution" does not happen to individuals. It happens to populations. It is the basis of speciel events and an individual does not constitute a species. Populations do. Individuals suffer mutations which add (maybe) to genetic variation within the population which leads to adaption (maybe) to changing environments. No individual evolves.
Mutations may or may not be in the "individuals" best interest. Mutations are random events that have whatever effect they have and the individual suffers or prospers accordingly.
Mutations [you]are[/you] in the best interests of the "population." Individuals with dilitarious mutations (usually) do not survive to reproduce, thus, for a population over many generations, survived mutations add considerable genetic variation to the gene pool.
When the inevitable environmental change occurs, the more genetically varied the population the better the chance that some combination of available alleles (ex-mutations now ubiquitous within the population) will produce individuals better able to cope (fitter) in the changing environment. Or maybe not.
As for Bot's desire for a faster rate of mutation rates:
Keep in mind that in a simulator like DB the mutation rate, and the rate of mutation rates, is synonymous with overall evolutionary time. One way to simulate great lengths of time is to have a high rate of mutations and a high rate of change in those rates. The other side of the simulation, to make this time scale accurate, must be a very short individual life span.
Since beneficial mutations, and allele variability, are slow to work through even a subset of a population, the higher the mutation rate the higher the generation "turnover" must be to weed out the bad (but lucky, since it may have been, by fluke, passed on to one generation) mutation and make the good alleles more frequent in the population.
In the absence of this, Shvarz has got it right. Not enough generations for natural selection to work, you end up with bad genes everywhere, very quickly. Back to brother Mueller and his silver ratchet. Or was that Maxwell and his silver hammer? Can't remember.