I think we are talking past each other. Also, my reasoning here is statistical rather than biological.
Disregarding selection and thresholds for a moment, Neutral standing variation doesn’t change for mean fitness of the population, but the variation in fitness (variance of the fitness) among members of the population will increase (law of large numbers). If the range of fitness with a population is small enough, then selective pressure cannot act to increase fitness. BUT with accumulating mutations, the variance will increase the range of fitness to the point where selection can begin to act, even if all the individual effects are negligible.
Thresholds and selection will affect this of course. Even if most mutations are detrimental, this will still increase the variance. IF slightly detrimental mutations become fixed so rapidly that the variance-of-fitness never increases, THEN GE might be possible. My intuition is this cannot occur in any realistic situation; the increase in variance from GE will force selection to come into play.
That claim would be incredibly easy for any GE believing Creationist to test. We have sequenced the genomes of plenty of preserved animals from the ice age - mammoths, musk oxen, wooly rhinos, bears, wolves, etc. We also have sequenced the genomes of most all large extant species. All any GEer has to do is publish a comparison of two genomes, say from a Dire wolf and a modern wolf - and show the decline in function or the decline in information content. But no one pushing GE has ever attempted this easy test.
I’ve already shown the genetic data from the 700,000 year horse find and asked why hasn’t that used by Creationists to compare to a modern horse genome but no one ever answered. Even if they thought the 700,000 year old genome was really only 6000 years old tops there still should be evidence of this claimed “decline” in a comparison. So why are Sanford and Carter and Price so loathe to actually test their claims?
But standing variation reaches an equilibrium as fixations reduce variation and mutations increase it. Whether the standing variance is enough for selection to affect would seem to depend on the average selection coefficient of the nearly neutral alleles.
Let’s recall that we’re only talking about non-selectable, nearly neutral, deleterious mutations. Selectable mutations are not relevant.
The vast majority would. It doesn’t matter whether the machine is perfect or not. It’s still much easier to damage a functional machine than to improve on it. That is a basic principle of logic that always holds true. This is the stumbling block that @glipsnort has fallen on repeatedly in these discussions. His discussion of “tolerances” is still a mystery to me, since tolerances would be blown out quite obviously as mutations continue to accrue. He would need to show a natural process that can somehow prevent mutations from ever changing past its engineered error tolerances. That would itself require a kind of supernatural oversight.
PDPrice still ignore the fact in biological life it’s easy to improve living “functional machines” when the environment changes. Then the improved versions get to reproduce more than the “damaged” ones and eventually become the new standard. That’s a basic scientific principle which PD just can’t seem to grasp.
Life forms don’t have “engineered error tolerances”. They can range in dimensions from the smallest microbe to the largest blue whale and all the sizes / shapes in between. I know one Creationist in desperate need of a basic biology course.
But humans do not have a large enough variance in fitness because of noise - we’re too complex for selection to be effective. This is the point of GE as I’m understanding it. But the increase in variance will force selection to come into play for other organisms as population size increases, generation time decreases, and complexity decreases. The differences should be extreme!
That’s how I understand GE. I think you got it too!
I’m wondering if you could describe your thoughts on this a bit more–If the virus is getting better at surviving by keeping its “food” alive, what is breaking down?
I’m also struggling to understand how something could be getting better at staying alive and reproducing, but is in fact not getting better at staying alive and reproducing. Would you be willing to ascribe the same sentiment to a complementary scenario? For example, if you came across a dead insect, would you say the insect is trending toward life?
Is there a way you might measure how well something survives and reproduces?
Again it doesn’t get better at surviving, it maintains its survival through the generations. But its instruction manual about how to do so continues to break down through each copy.
This is where I think “survival of the fittest” confuses. Fitness is about the next generation, not survival of the current one. We can copy the instruction manual for the next generation. It may include an innovation occasionally, but there will always be mistakes. In life and in biology.
No. That’s why I put my hope in the resurrection. We can’t see a dead insect come back to life except by a supernatural power.
Maybe I can use the idea of money to illustrate what I’m asking. I’m using unrealistic numbers here, but I just want to make sure we can agree on basic numbers:
If I put $10 in the bank and it accrues $2 in interest over a period of time, I now have $12 total. This means I gained $2 more than I started with.
Would you consider this a gain or would you consider this maintenance? I am viewing the extra $2 as a gain and I think you would agree with that.
No funny business. It just seems like we should find some common ground on the ideas of what gain and maintenance are first.
It is notable that @pdprice rejected a comment to the article that linked to creation.com, so our tolerance of him is not reciprocated.
This topic is now on a timer, and we will be considering carefully whether or not to allow @PDPrice to continue to post here unrestricted. I think other avenues of dialogue with creation.com might be more effective.
That’s not a basic principle of logic at all. It’s at best an inference from experience. And still it’s too vague to be meaningful, because it actually says nothing about the relative proportions other than X > Y. It doesn’t, by itself, say by how much, nor how the relative proportion is affected by changing the environment to which the system is adapted or how well adapted the system already is to those conditions.
Now it also happens to be the case that we know that the relative proportions of deleterious to beneficial mutations change as a function of how well-adapted the organism already is. We know that as we move ever higher in performance, the relative proportions shift towards more deleterious. Rates of adaptation slow down near a peak in the fitness-landscape. Which then implies the converse, that as we move back down it opens up more opportunity for change back to higher-fitness states. This is the stumbling block you keep running into, that you think the DFE is essentially fixed.
This is nothing but word salad. What does it mean to “blow out” tolerances? And what does it mean to “change past engineered error tolerances”? If you’re merely talking about preventing the accumulation of fitness-reducing mutations, that’s just natural selection. The reduction in relative reproductive rate entails selection against it. So now you have to make the assumption that the DFE stays constant and will always contain an overabundance of VSD mutations that remain invisible to selection. Yet we know it does not.
Yes, I am hoping we can explore a few different scenarios so we can have some sort of foundation to work from. I think it’s difficult to speak about the more complicated situation of genetics if we are unable to agree on gain versus maintenance or living versus dying.
Going back to the idea of money:
If I start with $10 and put it in the bank, it accrues $2 in interest, but then I take out $2 to pay for bank fees, I have maintained $10. Would you agree that this constitutes maintenance?
Understood and agreed. There may be (seem to be?) biological reasons that may limit the variability of the population, but I don’t know how to quantify that. I see no mathematical reasons to prevent variation from increasing.
Agree to this too.
I wonder if an allele might be so sensitive to mutation that any change would be strongly negative - and we see conserved sequences for this reason, as I understand it. This would prevent GE too.
Of course humans have enough variation. Roughly 20% of miscarriages are thought to be due to genetic incompatibility or defect, and that is selection too. We don’t have hard numbers on that because it’s very difficult to study directly.
Humans also have social selection factors. We may have overcome many biological factors, but selections are still being made. It kinda hard to see where those selections are taking us too.
But humans do not have a large enough variance in fitness because of noise - we’re too complex for selection to be effective. This is the point of GE as I’m understanding it. But the increase in variance will force selection to come into play for other organisms as population size increases, generation time decreases, and complexity decreases. The differences should be extreme!