Evolution Requires Reduction in Genetic Diversity

Hi Denisova,I think others have answered your questions. I'll just add that I think you can tell that I'm no shrinking violet, but you can't push on a string or herd cats. I don't think there's any forum anywhere that has ever solved the problem of how to turn on the light bulb for creationists. Just the fact that they've arrived at their position and likely maintained it for many years means that they have developed a complex catacomb of misconceptions and obscure justifications that defies simple facts and rational thinking.

Just a little while back in Message 549, and my own readings confirm this, HBD explained that the term gene frequency and allele frequency are often used interchangeably when it is allele frequency that is actually meant. I don't think Faith meant to imply that the it was actual genes whose frequencies were changing.But, and somebody please correct me if I'm wrong, I believe individuals in a population can differ as to which genes they have and how many. Some individuals may have different numbers of copies of some genes, or even possess genes other members do not. But I don't believe this is what Faith is talking about.

Agreed. I'll rule that the term allele frequency should be used when referring to allelic percentages in a population and related concepts, and the term gene frequency should not be used as it is confusing. If someone finds they need to talk about actual gene frequencies then they need only make it clear that that's what they mean.

Unless you can clarify, I don't see in what way HBD is off-topic. His point that drift, selection and migration are necessary causes of allelic frequency changes was made as a direct counter to your claim that allelic frequencies could change through isolation and nothing else. This paragraph might confuse a lot of people. HBD provided a summary of your position that seems right on to me, but you then accuse him of making it up, and then contradictively conclude that "it's simply what I happened to think."Or did you mean that he's making it up when he says that mutations can add diversity, because if so then I immediately rule that this is self evidently true, almost on the order of 1 plus 1 equals 2, even if only deleterious mutations are considered.Could you please clarify your meaning?

I've been trying to discourage inventing new terminology when existing terminology already exists, and in any case, I don't think you have to give up using the term "migration." When HBD says that in population genetics migration only means gene flow he only means that not only can a subpopulation migrate away, they can migrate back. I think your scenario is not just migration but migration followed by isolation. In your scenario a subpopulation migrates far enough away or encounters a significant enough barrier to become isolated from the original population, causing a cessation of gene flow between the subpopulation and the main population. Do I have that right?

Hi Faith,Maybe this has already been cleared up, but let me try again.You don't need the term migration. Your scenario only requires isolation. Physical migration is just one way to cause isolation, but it doesn't matter how isolation was caused. Physical migration is just the simplest and easiest to understand cause of isolation.So when you want to refer to the actual movement of a subpopulation from the location of the main population to another location I suggest you use the term physical migration, but realize that it is not a synonym for isolation, which is the situation you really need.Edited by Admin, : Improve clarity.

I don't think Wikipedia is saying this. Here's the Wikipedia quote you're referring to that you claim describes a way speciation can occur without mutation, copied from your Message 679: This opening summary doesn't mention mutation, but the mention of evolution implies that of course mutation plays a role, and if you read further through the article you'll find this: So Wikipedia is not claiming that the founder effect can lead to speciation without mutation.The unanswered question is how a subpopulation armed only with alleles already in the main population could arrive at genetically incompatible allele combinations. Unique allele combinations? Sure! Incompatible ones? How?

You're stepping out of line here.Also, I generally encourage participants to repeat their arguments as many times as necessary. Discussion boards are notoriously difficult for getting one's point across.

From the Forum Guidelines:

10. The sincerely held beliefs of other members deserve your respect. Please keep discussion civil. Argue the position, not the person.

Debate can be nuanced and complex, consisting of far more than just facts and arguments. If your goal is an admission of error then it is not enough to simply bombard your opponent with facts and arguments. You must coordinate your resources into a strategy that brings about in your opponent an admission of error, something Faith has done many times, including in this very thread.It is often observed that scientists with the best minds are the hardest to persuade to change their minds because they are so knowledgeable, and so skilled at marshaling that knowledge into a defense of their current position and an attack on the new position. It is also observed that new paradigms are rarely adopted by the old guard but only gradually become accepted as the old guard dies off. Changes of mind are rare, and admissions of changes of mind are even more rare.So use your facts and arguments to maneuver Faith into admissions of error. It's a much bigger challenge than merely demonstrating to yourself and those who already agree with you that you're right.

Concerning mutations that create new alleles, you seem to be saying that a new allelic combination involving existing alleles can create "completely new traits and functions," while a new allelic combination involving a newly mutated allele can only create "inconsequential traits." Is that correct?

I'm trying to discourage redefining existing terms. Mutations increasing genetic diversity is most certainly part of the definition of evolution.If what you're trying to say is that in your view mutations do not increase genetic diversity then that is self-evidently false. Using alleles per locus as the measure of genetic diversity, then if a new allele for a locus comes about via mutation it increases the number of alleles at that locus and must of mathematical necessity increase the alleles per locus.

I don't think you really mean "evolution" in the above passage. For example, you say that the passing on of various alleles in a population would not be evolution, but it most definitely is part of evolution.Might you mean "new phenotype creation?"

This doesn't help resolve the issue I raised, so I'm just going to rule that new allele combinations involving mutated alleles can have just as great an impact on phenotype as those involving existing alleles, and perhaps even greater.

Thank you. I was trying to figure out what you meant by, "You haven't described anything about evolution. You've argued that mutations increase genetic diversity. That's not evolution." I made a guess and asked if it was correct. You said no but nothing more, so I still have no idea what you were trying to say.

Uh, okay. So let me replace the word "evolution" with "microevolution" in one of your sentences: But alleles being passed on randomly within a population is most definitely part of microevolution, so I don't think you mean "microevolution" either. Thank you. That would be very welcome.