But we are talking about neutral mutations.
You're missing the key issue. While it's true that some individuals have more offspring because they have beneficial alleles and those alleles give a reproductive boost (by definition) to the individual, there's another possibility. That possibility is that even when individuals are on "equal footing" fitness-wise, SOME WILL PRODUCE MORE/LESS OFFSPRING SIMPLY BY PURE CHANCE. For a trivial example, one may have the bad fortune to be struck by lighting.
It should be trivially obvious that not all individuals end up having the same number of children, and that this differential is not entirely dependent upon genetic fitness. Luck, chance, other factors, call it what you will, plays a large part. Sometimes the big strong specimen gets hit by a car while the runt survives to reproduce.
This is what drives genetic drift.
An allele can reproduce faster than the general population only when it has a non-neutral effect (meaning that it has selective advantage). You look it up.
I *have* looked it up, which is why I can tell you that you're wrong. I told *you* to look it up in my previous post, you should have taken my advice.
If you had, you might have "looked up" such things as:
"If a population is finite in size (as all populations are) and if a given pair of parents have only a small number of offspring, then even in the absence of all selective forces, the frequency of a gene will not be exactly reproduced in the next generation because of sampling error. If in a population of 1000 individuals the frequency of "a" is 0.5 in one generation, then it may by chance be 0.493 or 0.505 in the next generation because of the chance production of a few more or less progeny of each genotype. In the second generation, there is another sampling error based on the new gene frequency, so the frequency of "a" may go from 0.505 to 0.510 or back to 0.498. This process of random fluctuation continues generation after generation, with no force pushing the frequency back to its initial state because the population has no "genetic memory" of its state many generations ago. Each generation is an independent event. The final result of this random change in allele frequency is that the population eventually drifts to p=1 or p=0. After this point, no further change is possible; the population has become homozygous."Or:(Suzuki, D.T., Griffiths, A.J.F., Miller, J.H. and Lewontin, R.C. in An Introduction to Genetic Analysis 4th ed. W.H. Freeman 1989 p.704)
"In other words, as long as the allele provides its bearer with no selective advantages or disadvantages whatsoever, its fate in the gene pool is totally indeterminate. It may disappear as soon as it arises (elimination) or it may proceed toward q = 1 (fixation) in a seemingly haphazard pattern that is aptly described as a random walk: the course taken by the allele depends entirely on how the gamete pool happens to be sampled from one generation to the next."For more technical treatment, see: Kimura 1968. Evolutionary rate at the molecular level. Nature 217: 624-628., or Kimura, M. 1983 The Neutral Theory of Molecular Evolution Cambridge University Press, or S. Karlin. "A first course in stochastic processes". New York, London, Academic Press. 1968.(Goodenough, Ursula in Genetics, 2nd ed. Harvard University 1978, p. 798-800)
If you want to look at the math, check out: Mathematical Methods of Population Genetics
(Sidebar: Why is it whenever anti-evolutionists challenge me to "look something up" it always supports *my* side when I do? Looks like *I'm* not the one who needs to be hitting the books harder.)
I already mentioned that it is a statistical percentage and that indeed you can get two or zero. This causes a problem for your theory because of the chance of it being none it shows that the mutation can indeed tend to dissappear in a fairly short number of generations.
That's no "problem" at all. Sure, a lot of mutations happen and then get lost in the shuffle. No one ever said they didn't. But what's important is that some *don't*, and these are the ones which become a part of the species' gene pool, available for further modification and recombination.
Just because a million people crap out on the lottery each week, that doesn't mean there aren't a bunch of lucky millionaires out there.
Therefore, again, Neutral mutations will not spread. The statistics which you keep claiming prove it show the exact opposite.
Simply repeating that doesn't make it true.
Yes, many neutral mutations occur and then are "shuffled out". But many survive and *do* spread, just on pure blind luck, in a "random walk" through the population. The ones that matter aren't the ones that die out, it's the ones which do manage to persist which provide raw material for further evolution.
I earlier urged you to run any of the simulations which are available on the net. You clearly chose not to do so, which was a mistake. If you had, you would have seen ample evidence of how neutral alleles *can* indeed spread through a population. For example:
This represent 8 "trials" of a low-frequency neutral mutation across 250 generations. Note that although 3 do quickly go to extinction (lower left), one (the grey line) drifts quite a bit up and down in frequency until it finally dies off about 200 generations later, two (turquoise and yellow lines) are still present in the population 250 generations later, and, most notably, two (the green and blue lines) have not only managed to spread through the population, they have entirely *supplanted* all competing alleles -- there is now nothing *but* the new mutation in the population.
Furthermore, note that the turquoise line came *very* close to "topping out" before it fell in frequency.
The statistical chances are the same and will even out over several generations that is why neutral drift is false.
If you say so... Feel free to "look it up" and provide me with a citation for that amazing claim. And I mean a reputable biology text or research paper, not a creationist screed, they tend to get their facts and quotes wrong a lot.
Let's remember that you only have one mutation, one single individual able to spread it.
To start with, sure -- but they have a chance to have children, maybe a bunch of them.
Let's also remember that the laws of statistics show that allele frequency will not change except with selective advantage.
There you go again...
No, the "laws of statistics" most certainly do *not* "show" this. Neutral mutations follow the "laws of statistics" in the same way as a ball bearing on a flat, level, vibrating floor -- they can go *anywhere*.
Again, you might want to "look that up" and get back to us.
Therefore in a large population, which is what you need for the many chances required for gradual evolution, the laws of statistics show that the percentage of the mutation will continue to be infinitely small and no larger than the proportion of the one individual in the original population.
Not exactly ("infinitely small" is notably incorrect), but I'll give you the obvious fact that a given mutation has a harder time "winning out" in a large population than a smaller one.
What you're forgetting, however, is that since the population *is* larger, there are more individuals who can *have* mutations.
Example: If the error rate is 0.1 per individual, then in a population of 100 there will be 10 mutations per generation (spread out across different individuals).
But in a population of 1,000,000, there will be 100,000 mutations per generation.
So yeah, while it's true that in the larger population any *given* mutation has a much smaller chance of becoming widespread, the fact remains that because there are many more *total* mutations, *one* of them still has a good chance of prospering. Again, like playing the lottery, the odds of winning suck, but enough people play that there is a frequent stream of winners.
In fact, interestingly enough, the smaller chance of a given mutation prospering in a larger population is *exactly* balanced by the fact that larger populations produce more total mutations. In other words, large populations have the same rate of "successful mutation" addition to the population as do small populations (where "successful" means "a mutation which has managed to spread through the most or all of population).
From the Introduction to Biology FAQ:
If mutations are neutral with respect to fitness, the rate of substitution (k) is equal to the rate of mutation(v). This does not mean every new mutant eventually reaches fixation. Alleles are added to the gene pool by mutation at the same rate they are lost to drift. For neutral alleles that do fix, it takes an average of 4N generations to do so. However, at equilibrium there are multiple alleles segregating in the population. In small populations, few mutations appear each generation. The ones that fix do so quickly relative to large populations. In large populations, more mutants appear over the generations. But, the ones that fix take much longer to do so. Thus, the rate of neutral evolution (in substitutions per generation) is independent of population size.(Copyright © 1996-1997 by Chris Colby)
Because of the complexity of genes and the need to change more than one base (indeed in my view you need completely new genes for new functions) this makes evolution totally impossible since a single base mutation will remain neutral until the complete series of mutations required to make a significantly more useful function has arisen and by the laws of genetics this is absolutely impossible.
You have made a number of invalid presumptions here, including:
1. You haven't taken into account the fact that many mutations are beneficial, not *all* evolutionary steppingstones are neutral.
2. This is especially true for changes that "build upon" an existing function.
3. "Completely new functions" most certainly do *not* require "completely new genes", the literature abounds with examples of a gene serving some prior purpose mutating and gaining a whole new purpose.
4. Being "significantly more useful" is not necessary, even being "slightly more useful" is more than enough of difference for selection to do its work.
5. You (vaguely) argue that something is improbable, then make an unsupported leap to "absolutely impossible". There's a vast difference between the two.
