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Lactose tolerance a key to evolution?

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beLIEf
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« on: May 25, 2011, 10:32:08 AM »

Evidence that we are still evolving, more fuel for the fire...

7http://www.bbc.co.uk/news/science-environment-12535647
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cyghost
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« Reply #1 on: May 25, 2011, 10:40:09 AM »

At this point in time no more fuel is needed really.

Anyone who denies evolution is denying observable reality and is delusional. More fuel is highly unlikely to change a delusional mind.

But cool link nonetheless  Cheesy
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beLIEf
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« Reply #2 on: May 25, 2011, 11:02:42 AM »

Very true, such is the nature of faith. But at least it's something tangible they could marginally relate to that doesn't involve God burying dinosuars or them thinking we used to be monkeys  Grin
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« Reply #3 on: May 25, 2011, 13:20:15 PM »

i wonder towards what we are evolving.
since we do less work, our limbs with atrophy, fingers might become longer.  even more hairless.  or, evolution might be negated completely by us going nano or having bodies cloned and our 'consciousness' uploaded to the new brain.
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« Reply #4 on: May 25, 2011, 15:14:23 PM »

i wonder towards what we are evolving.
Well, we're buggering up the ozone layer and putting a lot of dust into the atmosphere, so we'll need bigger and darker eyes.  We aren't doing as much physical labour, so we'll get skinnier and nerdier.  Most of our communication will be done via touch screens and the like, so our fingers will get longer and fewer.  After a while we'll end up looking like this:
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BoogieMonster
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« Reply #5 on: May 25, 2011, 15:38:38 PM »

Well, we're buggering up the ozone layer


Not anymore.
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Hermes
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« Reply #6 on: May 25, 2011, 16:42:56 PM »

Lactose tolerance playing a part in human evolution over the last 10 000 years makes a lot of sense.  Milk is very nutritious and the role it can play in natural selection is clear.  I am less convinced by the story of shorter, fatter people opting to have more children.  Have humans not been getting taller?  The theory is based on a rather small sample of humanity and also seems to be limited to female parents only.
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Mefiante
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« Reply #7 on: May 25, 2011, 17:26:55 PM »

Have humans not been getting taller?
That is much more the result of improved nutrition than of evolution.  Increased height doesn’t confer anywhere near the immediate survival advantage that an ability to metabolise lactose does in an agricultural setting.  Also, lactose tolerance is binary (either you can digest it or you can’t), whereas increased average height would be the cumulative effect over successive generations of slight advantages.

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beLIEf
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« Reply #8 on: May 25, 2011, 20:17:09 PM »

i wonder towards what we are evolving.

We aren't doing as much physical labour, so we'll get skinnier and nerdier.  Most of our communication will be done via touch screens and the like, so our fingers will get longer and fewer.  After a while we'll end up looking like this:


But apparantly kid's thumbs are getting bigger.....

http://news.bbc.co.uk/cbbcnews/hi/sci_tech/newsid_1892000/1892881.stm

Also I think the lack of physical labour is making us fatter and maybe the machines rather make us less intelligent rather than nerdier, so maybe a slightly dumber, fatter alien phenotype.
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Rigil Kent
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« Reply #9 on: May 25, 2011, 21:32:45 PM »

Hey, remember this song?
PUSA- Man (Opposable Thumb) Cover
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Hermes
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« Reply #10 on: May 25, 2011, 22:06:59 PM »

Have humans not been getting taller?
That is much more the result of improved nutrition than of evolution.
Perhaps I misunderstand you, but you appear to juxtapose improved nutrition and evolution as two independent causes.  If improved nutrition had no selective effect, it would only impact on the incumbent generation and not have any heritable permanency.  There is a cumulative aspect to humans getting taller.  Perhaps one should interpret it as indicative of improved nutrition causing both contemporary increased tallness as well as selective advantage.  Is that what you intended to convey, but that the former is predominant?
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« Reply #11 on: May 25, 2011, 22:42:33 PM »

No.  Tallness is not genetically fixed in the same way that lactose tolerance is.  In any generation, a biological individual may have a genetic predisposition to be taller than its siblings which may endow it with some or other survival (or reproductive) advantage, but that doesn’t mean that the individual will actually attain the potential tallness if the environment isn’t right.  The case of the Japanese (and now the Chinese, too) illustrates the point: current generations are taller than their progenitors because their nutritional standards are much improved, not because there’s been a spurt of tallness mutations.  That’s the point.

You could of course argue — and correctly so — that the ability to make provision for a healthier diet is itself a product of evolution, and, yes, this ability does indeed provide a selective advantage.  Tallness itself is merely a byproduct of that advantage, not the driving trait.

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« Reply #12 on: May 25, 2011, 23:39:13 PM »

Tallness is not genetically fixed in the same way that lactose tolerance is.
The exact tallness an individual attains is of course the product of both genetics and nutrition, but I am of the opinion that an evolutionary trend towards increased tallness can be discerned, if not in exactly the same way as the trend towards lactose tolerance, at least in a very similar way.  Your modern European is substantially taller than what (say) your Roman soldier used to be two millennia ago.  Reverting to the diet of that era would not result in Europeans, within one or a few generations, "shrinking" to that size again.  The selection driver is more obvious in the case of lactose tolerance, but tallness has genetically evolved and appears to continue doing so.
« Last Edit: May 26, 2011, 03:56:34 AM by Hermes » Logged
GCG
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« Reply #13 on: May 26, 2011, 09:34:08 AM »

when do i get to evolve boneclaws?
(does anybody know a place that deals with adamantium?)
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Rigil Kent
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« Reply #14 on: May 26, 2011, 09:43:59 AM »

Reverting to the diet of that era would not result in Europeans, within one or a few generations, "shrinking" to that size again.  

Good point. I suspect the observed increase in (potential maximum) height is at least partly due to sexual selection.

Mintaka
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