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Old 07-14-2010, 11:26 AM   #51
Steven Price
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Re: Study finds correlation between C.O.G. and Speed

Aushion,
As I mentioned in two posts above, documenting genetic differences between populations of the same species has been going on for almost 100 years. Butterflies, wild oats, pine trees, mice, zebra fish,….the list is endless. Over the decades one of the premier Journals that publishes this information is “Evolution.”
(http://www.wiley.com/bw/journal.asp?ref=0014-3820) wfs
I am at a University, so I can call this journal up and review content with no problem. If you are able to just look at the table of contents, you will see many articles documenting genetic differences between populations and trying to explain these differences via selection, migration, etc. (micro-evolution). The theory, or course, is that micro-evolution leads to macro-evolution, but that is a different issue here, but one I’d be happy to discuss with you off-line. To answer your question, YES, there is genetic differentiation WITHIN populations—in fact all populations of all organisms are found to be genetically variable for most characteristics (if not, the population is said to be “fixed” for that particular characteristic. However, although populations are genetically variable within populations, they are commonly found to be genetically variable BETWEEN populations, too. This can be so striking as to not require a statistical test, but all can be quantified using well-known statistical procedures.
There are many books describing these micro-evolutionary patterns. The best place to start is with the “classics.”
Dobzhansky, Th. 1970. Genetics of the Evolutionary Process. Columbia University Press, New York.
And
Variation and Evolution in Plants is a book written by G. Ledyard Stebbins, published in 1950
A more recent book covering DNA patterns and written for a more lay audience is “Endless Forms Most Beautiful” by Sean Carroll.
If you object to macro-evolutionary parts, just skip.
Again, if you want a little tutorial on any of this, let me know.
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Old 07-14-2010, 11:33 AM   #52
Katherine Derbyshire
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Re: Study finds correlation between C.O.G. and Speed

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Originally Posted by Aushion Chatman View Post

So then why would micro-evolution have necessarily played a part in what we observe today? Couldn't the answer simply be that there are literally millions of genetic possibilities... And in any community that has been segregated so that only certain genes are allowed to be expressed through procreation AND coupled with remaining in the same environment, can we reason that over time, certain nations have certain traits and other nations have other traits that have become dominant? I think we can.
Umm... That's what micro-evolution *is*...

Katherine
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Old 07-14-2010, 11:57 AM   #53
Joe Bellisano
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Re: Study finds correlation between C.O.G. and Speed

To me, the theories of micro-evolution are absolutely plausible. Let us simplify it (for this threads sake) and think about it like this: how animals change to become bigger or smaller, but they don't necessarily change the species in its entirety. This falls under the concepts like genetic drift (gene variation due to random sampling) and/or mutation/migration (movement of genes from one population to another). "Gene flow is hindered by mountain ranges, oceans and deserts or even man-made structures such as the Great Wall of China, which has hindered the flow of plant genes." Example: a turtle may get bigger or smaller over time, but it never becomes a snake. So, I guess that would fall under the theoretical assumption of micro-evolution. Not saying it is absolute; however, it is interesting to see how it could have and may have had it's impact on certain plant, animal, and insect species.
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Old 07-14-2010, 12:06 PM   #54
Joe Bellisano
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Re: Study finds correlation between C.O.G. and Speed

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Originally Posted by Katherine Derbyshire View Post
Umm... That's what micro-evolution *is*...

Katherine
To my understanding macro-evolution is changes in organisms that are considerable enough that the newer organisms would be considered a new species. To paraphrase that, if they would be put together, they would be unable to interbreed.
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Old 07-14-2010, 12:15 PM   #55
Steven Price
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Re: Study finds correlation between C.O.G. and Speed

Joe, you are correct. That is the model. Micro-evolution is pretty well established and accepted; taking that to the next step of macro-evolution is controversial in some quarters. Though here again, IMO, the evidence is overwhelming at all levels--genetic, organismal, populational, taxonomic, and geological. But a bit off this thread!
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Old 07-14-2010, 12:25 PM   #56
Jamie J. Skibicki
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Re: Study finds correlation between C.O.G. and Speed

"So then why would micro-evolution have necessarily played a part in what we observe today? Couldn't the answer simply be that there are literally millions of genetic possibilities... And in any community that has been segregated so that only certain genes are allowed to be expressed through procreation AND coupled with remaining in the same environment, can we reason that over time, certain nations have certain traits and other nations have other traits that have become dominant? I think we can.
"

Aush,

I think you just described the process of micro evolution, genetic traits within a species driven environmental and cultural differences from other members of the species who do not interbreed.

And I 'm late to the party, carry on.
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Old 07-14-2010, 04:29 PM   #57
Aushion Chatman
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Re: Study finds correlation between C.O.G. and Speed

I understand what you all are saying...but just because a certain trait has proved dominant doesn't mean the other traits have been stamped out. Which to me means there is no mechanism driving these traits to adapt to the environment. It simply means that certain traits are dominant in a given population in an environment. A subtle but profound difference IMO.

So maybe most Maasai are tall...maybe they've been that way for a long time. maybe you can trace the Maasai tribe back to two families...both above average height who moved out into the middle of the country...they had kids...their kids had kids...and today we see an above average height community. But there was no "evolution" it was simply that given what was available genetically to breed with, they wound up with a bunch of tall people. There was no genetic CHANGE. Just genetic preference...I believe it is entirely possible for the Maasai to have (at random) a large number of smaller children, who reproduce with other children dramatically reducing the average height of the Maasai...is that necessarily "evolution" or just a numbers game?

I think it has more to do with math, then some sort of response to the environment. But I'm a physics guy so I'd rather see Math driving the world then some ethereal cognition of cells to help an organism survive. Have evolutionists determined what that mechanism is that drives changes?

There would need to be some sort of environmental feedback loop that says..."hey it's cooler here, let's develop lighter skin so we can harvest more Vitamin D" How does the skin cell get that information? From who from where by what means? I just feel like there is a lot of Jedi Mind Tricks when it comes to whole-heartedly believing that. It would take energy for that information to be relayed on a constant basis to your DNA so that the sperm and eggs produced start to develop traits that are a better fit for the environment, has anyone attempted to measure that?

I will look into that research you provided though Steven THANKS! I may hit you up off-line after reading a little. Amazon.com awaits.
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Old 07-14-2010, 05:09 PM   #58
Jamie J. Skibicki
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Re: Study finds correlation between C.O.G. and Speed

Aush,

Take the vitamin d thing. THe lighter the shade of skin you have, the less sunlight you need to get the vitamin d you need. I'm assuming you have read Steven lows treatise on the lack of vitamin D. If you have less vitmin D, all other things being equal, you are at a disadvantage. The people with lighter shades of skin would get more food, be more alert, etc and therefore reproduce more. THis would mean each subsequent generation would be predisposed to have lighter skin.

The adaptation which is the biggest benefit to securing breeding partners is the one that will win out. Thats it.

"It would take energy for that information to be relayed on a constant basis to your DNA so that the sperm and eggs produced start to develop traits that are a better fit for the environment, has anyone attempted to measure that?"

I have no idea where you are going with this. It's not "it's pretty shady here, lighten up the skin". Skin color is variable to some degree based on genetics. having lighter skin color in shady climes is an advantage (see above). this trait gets passed on becuase in shady climes, lighter skinned people get more breeeding partners.

If you live in an area where running long distance was desirable or encouraged culturally (by encourage I mean in such a way as to increase the number or c hance of you having offspring) then after several generations, most of those people would be good long distance runners.
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Old 07-14-2010, 05:28 PM   #59
Steven Price
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Re: Study finds correlation between C.O.G. and Speed

Aushion, since you are a physics guy you will be glad to know that population genetics is mostly math. The phenomenon you describe, ie, random fixation of traits, is well known--it is called "genetic drift" or "founder effects". The point you are making is that just because there is some association of a character with a particular race does not mean that this came about because of natural selection--ie, it was randomly fixed "in". Yes, of course, this is a well known phenomenon. Especially amongst organisms that are dispersed in small populations--smaller the population, the greater the chance of getting "fixation." And the evidence is that Homo sapiens was probably, in fact, dispersed in very small populations. This would mean that "drift" was probably a very important factor in the micro-evolution of humans. This does NOT, however, say that the genes that were fixed were not adaptive in the environment where they were initially fixed. The real question you are asking, I think, is how much of the differences we see amongst humans is adaptive--that is, are the differences we see due to adaptive effects. A test of this is to look at the distribution of fixed traits--if they were randomly fixed in, then there should be no environmentally associated pattern--in fact there would be a hodge-podge of different traits from population to population. But in fact we find MANY environmentally associated patterns in humans and other organisms that show statistical associations with environments--again, the references I gave you addresses these. Also, the origin of these genetic differences are ultimately gene mutations, of which there are multitudes being "tossed" as dice every day under every rock and leaf. DNA loves to mutate. Finally, through out the genome there are regions that are under selection and those that are not, other regions "hitch-hiking" along with selected traits. None of this has to do with mind Jedi tricks--now action at a distance between protons, now that is spooky. If you are a particle physicist I can see why you might say that. Fortunately string theory does not seem to overlap with Newtonian physics, yet....
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Old 07-14-2010, 08:24 PM   #60
Aushion Chatman
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Re: Study finds correlation between C.O.G. and Speed

Steven,

No doubt I need to research more...I'm sure I haven't had any original thoughts on evolution that haven't already been brought to light given the wide dissention among belief on this topic.

Jamie

What you seem to suggest is that people would die off because of some trait that is less advantageous...I don't believe that's the case, I think the discrepency would need to be something much more drastic than being vitamin d deficient or short or less athletic...

What I mean is, humans can live and reproduce in very sub-par states of being...look at the overweight in America having kids that are overweight who go on to have kids that are overweight. I understand being overweight may or may not have much to do with genetics...(that's a whole other can of worms) but you see my point. Probably a bad anecdote.

So my quesion is, what observable trait is so detrimental in any human you see today that would suggest that those people would die off? It just doesn't happen, there are no humans today that are going to stop reproducing or die off because they express this or that detrimental trait. Which in my limited understanding would mean we have ceased to evolve (if we ever evolving in the first place) as there is now no noticeable adaptation that needs to take place to live and reproduce...
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