"Best" evidence for evolution.

And a shorter way to say that would be???

And a shorter way to say that would be???

That's a bottleneck. Yes, that's what bottlenecks do.If two bison separate from a herd of 100,000, the two have less genetic diversity than the 99,998. (But overall there is no reduction in diversity.)If 50,000 separate there is probably no loss of genetic diversity. But so long as they never meet again the two populations will diverge. And that exactly what they do do - introduce a change from time to time. That all evolution is.

Make it a hundred that separate from a population of a thousand. I'm not talkinjg about a bottleneck, I'm talking about some normal number that would emigrate, some portion of a population that would possess less genetic diversity and that means just about any smallish portion. It would possess its own set of gene frequencies which is how you get the new traits in the new composite phenotype of the new species in the ring. If half the population emigrates then there will probably not be a lot of change but there will probably be some, and in this case in both populations.

Just saying that if a population evolves to look like and behave like another population, that for all intents and purposes it has become a different kind, based on how "kind" is defined. Convergent evolution is explained by similar ecological pressures. This is why there are several differently evolved gliding tree frogs -- it's easier to get from tree to tree and to evade predators. Evolution explains it quite well, adaptation to specific ecological habitats, over time becoming more and more adapted to those habitats.Whether we are talking about evolution within a clade (biological/evolutionary) or within a "kind" (creationist) the result is the same -- adaptation to specific habitats brings out specific adaptations. Their "specificity is too wonderful for that explanation" is easily explained by adaptation over many generations from the parent Clade/"Kind" population. This of course gets us into the question of how much time is involved: I have billions of years, you just a few thousand years, so they had to evolve at a much faster rate for your view than mine. Agreed, and again the issue of time is raised -- how fast they evolved generation by generation. Just as we saw with the mammal ear evolution.Out of interest where do you put hyenas and thylacines? They appear similar to dogs imho, more convergent evolution? Did the thylacines evolve to be like dogs for all intents and purposes? Which is irrelevant if there was not flood. Like microevolution generation after generation after generation ... where I have plenty of time and you don't. False assumptions lead to false conclusions. Because they evolved to work together as they evolved. Again the issue comes down to time, which makes small steps over many generations over billions of years an adequate explanation, but limiting it to a few thousand years much more difficult. You need hyper-evolution and many lumps to get there, while evolution doesn't. That makes evolution the better explanation.EnjoyEdited by RAZD, : finished

That would be a bottleneck. There is no such thing as a 'normal number'. There is a minimum number though, that's the number at which the likelihood of survival is higher than the likelihood of extinction. That's actually quite a high number. The two populations will stay the same for as long as there's no environmental pressure for them to change. If the environments are the same, there will be little change. If they are different there will be greater change. (See Darwin's finches) If they are very different it's probable that one or both populations will go extinct.You may be interested in this

quote:

---

Following a population bottleneck, the remaining population faces a higher level of genetic drift, which describes random fluctuations in the presence of alleles in a population. In small populations, infrequently occurring alleles face a greater chance of being lost, which can further decrease the gene pool. Due to the loss of genetic variation, the new population can become genetically distinct from the original population, which has led to the hypothesis that population bottlenecks can lead to the evolution of new species.

---

Absolutely, juist what I'm talking about although I haven't regarded such a large portion of a population to be a bottleneck. But as usual that's just a semantic glitch people like to throw ibnto the discussion from time to time. No problem, the wpoint is that the smaller population WILL lose the infrequently occurring alleles and under those circumstance some dramatically new traits can develop and create a new composite phenotype quite different from the parent population and all the others in the ring species. This is due to the loss of genetic diversity, in this case the loss of the low frequency alleles. Just what I've been saying has to happen. And they call the resulting new population with its own new traits a "species." I'd call it a "subspecies" or variation myself, and since this is a ring species another population will develop out of this one two by the emigtation of some number to a new location where it will also develop its own peculiar composite phenotype due to reduced genetic diversity.

No, it's a way to reduce confusion and promote communication. You THINK you have, but your "proof" relies on a hidden assumption -- that mutations are inadequate to increase genetic variation, when this is obviously not the case.A "proof" based on false assumptions is not valid.Enjoy

It's not an assumption, I've worked it out. First you can't maintain a species in the wild or a breed in artificial selection if you have any kind of increase in genetic diversity, wether through gene flow or mutation. Since both breeds and species in the wild maintain an identifiable characteristics we know that neither of these sources of increase occur, or that they are extremely rare.Second, if such increases do occur, usually from resumed gene flow rather than mutation, since mutation doesn't contribute much change in a short period of time, then if a population split occurs or any other kind of selection we will again have reduced genetic diversity which always occurs when new traits form a new composite phenotype. Selection IS the driving force of evolution and it always decreases genetic diversity.

quote:

---

It's not an assumption, I've worked it out

---

As we will see, you haven’t.

quote:

---

First you can't maintain a species in the wild or a breed in artificial selection if you have any kind of increase in genetic diversity, wether through gene flow or mutation.

---

That is obviously false. Maybe there is some sort of maximum to diversity but it is far from clear that any species has come close to reaching it. And if they have not then more diversity can be added.

quote:

---

Since both breeds and species in the wild maintain an identifiable characteristics we know that neither of these sources of increase occur, or that they are extremely rare.

---

Species are not breeds. Breeds are derived from species and the breeds in aggregate will show greater phenotypic variation. Even if the breeds have less genetic diversity than the wild species they were derived from. Clearly it is NOT a simple matter of genetic diversity.

quote:

---

Second, if such increases do occur, usually from resumed gene flow rather than mutation, since mutation doesn't contribute much change in a short period of time, then if a population split occurs or any other kind of selection we will again have reduced genetic diversity which always occurs when new traits form a new composite phenotype.

---

Why assume only a short period of time? Not that population splits tend to greatly reduce diversity even if we consider the sub-populations against the combined population.

quote:

---

Selection IS the driving force of evolution and it always decreases genetic diversity.

---

Selection is the guiding force. Mutation drives it by providing the necessary diversity.

All populations that have an identifiable homogenous composite phenotype (to use dwise's term which I think is a good one) have a reduced genetic diversity compared to the parent population they came from. It's got nothing to do with any "mqaximum" of diversity, it's a relative thing: daughter populations formed from a small portion of the parent population, that form in reproductive isolation, and are not subject to gene flow, have reduced genetic diversity from the parent population. instead of just pronouncing me wrong you have to prove me wrong and you always fail to do so.Breeds are just like this kind of populaton in the wild that forms from a limited number of individuals in reproductive isolation. Genetically it's the same situation and reduced genetic diversity is always the necessary concomitant to the development of the new population or subpopulation or species or subspecies or varliety or whatever you want to call it.Mutation really has no role in this as I discussed above, and most of it is just wishful thinking anyway, as beneficial mutations don't occur frequently or fast enough to have the effects you imagine. Besides which, as I show above, they would only destroy any newly formed subpopulation's composite phenotype, or any breed, if they did occur, because they are just one form of gene flow which destroys what selection is trying to do.Edited by Faith, : No reason given.

quote:

---

All populations that have an identifiable homogenous composite phenotype (to use dwise's term which I think is a good one) have a reduced genetic diversity compared to the parent population they came from.

---

I disagree. It will take time, but if the daughter population is successful I expect it to catch up with the diversity of the parent population. There is no reason why it cannot.

quote:

---

It's got nothing to do with any "mqaximum" of diversity, it's a relative thing: daughter populations formed from a small portion of the parent population, that form in reproductive isolation, and are not subject to gene flow, have reduced genetic diversity from the parent population.

---

What you originally said definitely DID relate to a maximum, since you claimed: That is NOT relative.

quote:

---

instead of just pronouncing me wrong you have to prove me wrong and you always fail to do so.

---

Of course I have succeeded in proving you wrong on occasion. However, I need not do so, I only need to show that you lack a good case for your position.Indeed, even here you are arguing a different point rather than defend your original statement - and even so you have not made a case.

quote:

---

Breeds are just like this kind of populaton in the wild that forms from a limited number of individuals in reproductive isolation.

---

No, they are not. Produce examples if you disagree. Genuine examples, not recognised species.

quote:

---

Genetically it's the same situation and reduced genetic diversity is always the necessary concomitant to the development of the new population or subpopulation or species or subspecies or varliety or whatever you want to call it.

---

But it is only temporarily necessary. There is nothing stopping diversity from increasing again.

quote:

---

Mutation really has no role in this as I discussed above, and most of it is just wishful thinking anyway, as beneficial mutations don't occur frequently or fast enough to have the effects you imagine.

---

You are the one engaging in wishful thinking, not least because neutral mutations are quite sufficient to restore diversity. You have no numbers to back up your claims.

quote:

---

Besides which, as I show above, they would only destroy any newly formed subpopulation's composite phenotype, or any breed, if they did occur, because they are just one form of gene flow which destroys what selection is trying to do.

---

You have never shown any such thing. You just keep saying it, without even an attempt to support it. Why do you say these things when you must know they aren’t true?In reality selection is not trying to do anything and the idea that new variations must directly target the loci under selection is obviously foolish. Yet if those loci are not targeted the obviously there can be no interference with selection. You obviously have not thought it through.

So you are claiming that at a certen point a species would no longer be able to change because of a loss in genetic diversity if they are separated from the pack?Um soo... how do asexual organism change/evolve then?
From the moment they are borne they are separated from their populations genome, they cant exchange chromosomes or genes as they do not have sex. And given that their life cycles are shorter even in a 6000 year old universe they should have run out of genetic diversity and be unable to change/evolve, and yet they do.
Could it be that mutations play a larger role than you think?

"Being separated from the pack" has nothing to do with anything I've said.

You claimed that the changes we see are do to a loss of genetic diversity, when species undergoes a bottleneck. Well asexual beings go trough a bottleneck at birth. Each is an island un to its own, and yet they keep evolving/changing. How?