Forgive the sloppy post, 7:30 is not a time when I am usually awake.
Really? The experts seem to disagree.
“Genetic interchange between Africans and non-Africans is also suggested by a Y-DNA haplotype tree [9"] and
a hemoglobin 13 locus tree [13"]. The hemoglobin data make a particularly compelling case against OAR because
the coalescence of an autosomal gene is expected to be about four times as old as that of a uniparental haploid
genetic element and this seems to be the case [13"’]. Consequently, the patterns of widespread gene flow across
Africa and Asia with isolation by distance observed with the hemoglobin locus appear to predate the hypothesized
replacement event.”
Templeton, A.R.
Out of Africa? What do genes tell us?
Current Opinion in Genetics & Development 1997, 7:841-847
Care to elaborate on your belief that such constant genetic intechange never occurred?
Can you perhaps provide a reference to support your contention that there was no constant interbreeding between European and Africans?
Sure, any number. But let’s cut the strawman. We are not arguing whether or not ‘If a trait is detrimental, and present less of a survival advantage, it will disappear’ We are arguing about your actual contention that ‘change must produce a survival advantage before DNA is passed on’. Those are very different. In one you are arguing about selection against negative traits, which no one disputes. What I take issue with is your claim that a trait must be advantageous to be passed on. That is simply nonsense.
Want an example? Well here is one:
“For example, if a population of green and red moths is preyed on by a colorblind predator, any differences in reproductive success between the two types will not be
due to the physical differences between the moths. As a result, particularly if the population is small, there may be a change in the distribution of types in the population over the course of generations. For example, the population of moths might become entirely red. This would be evolution, but not adaptive evolution. Thus, random drift is another possible mechanism of evolution, but it is a mechanism that tends to lead to an increase in <b>nonadaptive (read: neutral) traits</b> rather than adaptive ones”
philsci-archive.pitt.edu/archive/00001139/ 00/Millstein_Evolution4.pdf
I hope you now understand how totally erroneous it is to suggest that traits that are neutral, and hence produce no survival advantage, can not be passed on.
If you still struggle with this basic concept I suggest S.J. Gould ‘Hen’s Teeth and Horse’s Toes”. But please don’t make references to Darwin turning in his grave when you clearly don’t understand something that is completely non-controversial in the biological sciences. No scientist in the world doubts that changes can be passed on without producing survival advantages.
And what would that assertion be based on, pray tell?
Evolution - Change in the genetic composition of a population during successive generations, as a result of natural selection acting on the genetic variation among individuals, and resulting in the development of new species.
I hope you now understand that posting crap you made up makes you look, well ‘less evolved’. You see, I never said, “traits that are neutral, and hence produce no survival advantage, can not be passed on.”
I said that evolution was advantage-driven and not disadvantage-driven.
I said, “If a trait is detrimental, and presents less of a survival advantage, it will disappear.”
But I never said neutral traits couldn’t be passed on.
Really, which experts are you speaking of? Because the ones you quoted…don’t. The rest of the study doesn’t and, for that matter, neither does the text you pasted in. In fact, the text you’re quoting deals with the migration theories of Homo Sapiens from the evolutionary Eden. It does say:
But that doesn’t even come close to bolstering your claim that ‘constant’ inbreeding occurred.
I don’t think I have to. I think that it’s common knowledge and sense. In the same way I shouldn’t have to explain why I think the earth is round or that dogs can’t do algebra. It’s a no brainer!
If we were swapping the genes with everyone else on the planet, how did such diverse groups come to be? Why are Europeans light-skinned and Africans dark-skinned? Why do the Inuit have extra layers of fat?
If we were all interbreeding, why haven’t we ever heard of a white Zulu warrior? Of a Celtic Pygmy? An Asian knight of the Round Table?
These people were separated by thousands of miles. Now, I’ve traveled for a piece, but to freekin’ Africa! And walking, no less. C’mon!
Oh, back to that again. Well I agree. It is nonsense. Because I never said it. (I’ll explain more in a minute)
I was looking for a real-life example, not a hypothetical one. That text explains how something can occur, not how it did occur.
I think the problem, here is that you believe that passing on a trait is evolution. It’s not. What you’re talking about is the propagation of mutated DNA. If that mutation produces an advantage, and is passed on to subsequent generations, then you have yourself some evolution.
My advice to you, if you still struggle with this basic concept is to pick up a copy of S.J. Gould ‘Hen’s Teeth and Horse’s Toes”.
But please don’t drag Darwin down with you, when you clearly don’t understand something that is completely non-controversial in the biological sciences.
On the other hand, I see you’ve mastered that ‘Preview Post’ button. Kudos!
By the way, I still say hair is for sex appeal.
What you said was, and I quote, “change must produce a survival advantage before DNA is passed on’”.
By defintion neutral traits can not produce a survival advantage. But according to you traits ‘must produce a survival advantage before DNA is passed on’. Therfore by your tandards neutral traits can not be passsed on.
That is completely incorrect and displays gros signorance of evolutionary theory.
However since I have now corrected this point I think we can let it rest.
In fact prcroughn I think we can let the whole thing rest there.
I have provided reference that say that there was ‘widespread gene flow across Africa and Asia’, and yet you simply assert that the article never makes that statement.
There is little that can be done to help the willfully ignorant when they refuse to acknowledge the facts presented in black and white. I hav presented the facts, you deny they even exist. You have so far failed to bring any facts at all to the discussion, just your baseless opinion. You clearly wish wish to remain ignorant. There is nothing else I can do.
You’re paraphrasing, my friend. You’re taking my words out of context. What I said was:
It was only seven extra words. But those seven make the difference. A change has to produce survival advantage to be ‘evolution’.
I’m not trying to be picky, but that’s what I said. So stop twisting my words. Especially since they’re shown right there on this page. It’s not like any of us can’t just go look at them. They’re right there!
Heh-heh.
Maybe I missed it. Can you provide a link so that I can read exactly what you are reading? Especially the part about it being ‘widespread’.
My favorite part, of your latest post, is how you suggest that we let it rest and take a few more swings. “Willfully Ignorant” Maybe I’ll change my name to that.
On that off chance that you are right, I’d like to ask others to comment on the discussion. Perhaps I’m not seeing things the right way. Am I missing something? I have been wrong before. Please, anyone who sees this thread, give it to me straight and straighten me out.