A barrier to macroevolution & objections to it

I'd like this to be more or less a continuation of the thread, What is the mechanism that prevents microevolution to become macroevolution?, on which I argued as usual for the mechanism of reduction of genetic diversity through selection and population-splitting processes, but I'd like to extend it to include the claim that mutations can overcome this barrier to macroevolution. But since it's apparently hard for the argument about the reducing processes to stick in anyone's mind, it needs to be reviewed.On that thread at the very end, Percy said: I would say it's unfortunate that Percy didn't read more of the thread since he missed the whole argument that answered his walking analogy.When the same doubt about the topic's being addressed came up earlier in the thread, Ben answered it quite well:http://EvC Forum: What is the mechanism that prevents microevolution to become macroevolution? -->EvC Forum: What is the mechanism that prevents microevolution to become macroevolution? Percy continues: This has been answered already many times by my argument. The only way the walking analogy would work at all, and then not really, is if you modify it to say that micro-walking is like a steep uphill hike in which baggage is periodically jettisoned from the backpack to make it easier, until you arrive at the foot of a sheer vertical cliff without any of the gear that would be needed to scale it (macro-walk it), because it has been jettisoned along the way. THAT is the boundary between micro-and macro-evolution, and the path to that point is the definition of the Kind. Defining that boundary is the whole point of my argument. The boundary is the fact that all the processes of evolution either maintain genetic diversity while varying frequencies of alleles, or reduce genetic diversity by eliminating alleles from new populations, the very populations considered most likely to lead to speciation, and the overall trend of this is slow reduction.There is nothing whatever that could increase it except mutation.Adding mutations to this is really more like interfering with a perfectly well-designed system than it is furthering anything useful, but on the assurance given by evolutionists that mutations do indeed provide useful alleles and increase genetic diversity enough and in the right direction to power evolution through to macroevolution, I've asked for evidence that this is so, and all I get is the usual short list of supposedly beneficial mutations. This does not meet the requirement, about which I'll say more in response to the following:RickB in http://EvC Forum: What is the mechanism that prevents microevolution to become macroevolution? -->EvC Forum: What is the mechanism that prevents microevolution to become macroevolution?: A logical conclusion is a logical conclusion. There is no other from the premises I have assembled, which you do not bother to mention, preferring to make an unsupported pronouncement. I've rejected the evidence as insufficient and therefore no evidence at all, if it's meant to demonstrate increase in alleles and genetic diversity after speciation. To do that you'd have to actually MEASURE alleles in a population after speciation, you can't merely assume that the occasional beneficial mutation in another species is sufficient to prove this. And the ball is in your court, not mine, because I've shown that all the other processes reduce genetic diversity, so it's up to those who claim mutation overcomes this to prove it. The whole point of the discussion about all the processes that reduce genetic diversity is that they come up against a brick wall beyond which no further variation or evolution is possible. Wherever this barrier is found is the outer edge of the Kind. You may want a definition, but a barrier should do as well instead.But also, in another thread MJFloresta suggested that a Kind might be defined by all that could be interbred even artificially, assuming that some species simply stop interbreeding from lack of inclination rather than inability, and I thought that possibly a useful way to think about it. Then kuresu posted a list of hybrids that is quite extensive, and intuitively satisfying as a suggestion for what a Kind would include, which I thought would be a great start toward a definition of the Kinds. It's not that we haven't offered some thought along these lines.Anything that clarifies the argument about the processes that reduce genetic diversity or supports the claim that mutations overcome this effect should be on-topic in this thread. Edited by Faith, : No reason given.Edited by Faith, : No reason given.

Thread copied to the A barrier to macroevolution & objections to it thread in the Biological Evolution forum, this copy of the thread has been closed.