Puzzle--how to get around these apparent dependencies of the modern synthesis on supernatural powers?

Natural selection works by whittling down the number of less-fit variations. As fast as it does so some agency must add new variations, otherwise natural selection would run out of variations to select from and evolution would cease. Failure to find a non-supernatural agency able to account for the creation of new variation led to natural selection being almost abandoned after Darwin's death.

But did the addition of genetic mutation help? Genetic mutation by itself leads to harmful mutations that, accumulating generation by generation, would lead to rapid extinction. Natural selection's effect, being so slight, can do little to slow that accumulation. But according to population statistics, when that slight effect acts in favor of beneficial mutations it can increase their incidence to make them the dominant form of their gene, although that would take millions of generations. For that time to be availalble something must be suppressing the accumulation of the harmful mutations that would otherwise lead to extinction in just a few generations. That can only be supernatural powers in the beneficial mutation.

Illustration: Take two species competing in the same niche. Both suffer genetic mutation but the second one has a perfect repair mechanism so no mutations survive into its phenotype. Until beneficial genes appear in the first species it accumulates harmful genes and extinction threatens. But once a beneficial gene appears, all that accumulation of harmful genes must supernaturally disappear and only beneficial mutations will increase in incidence, leading after millions of generations to eventual evolution and dominance in the niche. Without this supernatural power of the beneficial mutation, how else how can one account for mutations helping species evolve?

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Replies to This Discussion

Joan, I regret the way I expressed my point. My point is simple math:

  • if in each generation there are 1002 harmful mutations and 2 beneficial mutations, and all carry a value of fitness of plus or minus one, then the sum of harm and benefit together in each generation is -1000 units of fitness (- 1002 + 2). If natural selection had zero effect, then as generations pass the sum increases in arithmetical proportion as, -1000, -2000, -3000, -4000 etc until the loss of fitness reaches the point of making the species go extinct. Note; "harmful" means mutations persist, they are not lethal until their cumulative effect is lethal.

  • Now give natural selection some effect, instead of zero, say, 2%. Let's assume it lets all beneficial mutations through but reduces the number of harmful mutations in each generation by 2%. Then the totals change to around  - (1002 - 20) + 2 = 980 in generation one (compounding won't have much effect on numbers of harmful mutations for several generations) : -980, -1960, -2940 etc, ie natural selection does reduce the amount of harm passed on, but not by enough to prevent extinction.

  • To prevent extinction you need to get rid of at least 99.9% of harmful mutations in each generation, for the accumulation of fitness to be to be positive in each generation, as this mechanism of evolution would demand. That's an efficiency of natural selection of close to 100%.

So it's a mathematical problem. So far, I've not found anyone who can explain to me where the problem is. I see only four answers:

  1. the efficiency of natural selection really is 100%

  2. "Harmful" really means "lethal" so they disappear of their own accord, you can ignore them.

  3. my logic and maths is faulty (no one has yet pointed out where I've made an error grave enough to account for the problem)

  4. the maths are applied differently to beneficial mutations and harmful mutations (I sarcastically referred to that as "supernatural.")

If 3, can you point out my error?

I know I should have put it this way first, but when I do no one takes it seriously, So I made a joke of it, saying I believed answer 4, and challenging anyone to prove me wrong. Sorry.

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