General Question

Izzard's avatar

Wouldn't it make more sense to be dark-skinned in cold climates and light-skinned in hot ones?

Asked by Izzard (70 points ) June 14th, 2009

Melanin protects from the harmful effects of the sun, but…

Dark surfaces absorb heat and light. Light surfaces reflect heat and light. So does this mean that dark-skinned people are heated up more by the sun? If so, wouldn’t it make more sense to be more “reflective” when you live near the equator and more “absorbent” further from it? (I’m not trying to second-guess evolution here – it just occurred to me that it’s counter-intuitive when you look at it this way. So it’s sort of a rhetorical question but I thought it would be fun to discuss.)

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57 Answers

DarkScribe's avatar

Not really. Dark skins resist sun damage far better than light. As we all tend to be clothed, dark and light, a dark skin when clothed would retain more heat.

Jack79's avatar

I’ve also wondered this many times Izzard. Apparently having dark skin is the result of staying in the sun, and not an evolutionary tactic. Never really understood that one to be honest.

brownlemur's avatar

Actually, it has a great deal to do with surface area to volume ratios. Those who live in hotter climates close to the equator tend to be tall with long arms and legs, thereby facilitating the release of heat. Those who live farther away from the equator and closer to the poles tend to be shorter and stockier, and can better keep heat in. Skin color does have to do with sun exposure on many levels, and a high SA:Volume ratio mitigates the heat dissipation/retention problem. Check out cool concepts like Bergmann’s Rule and Allen’s Rule.

evelyns_pet_zebra's avatar

Great Question, I’ve always wondered about this.

mammal's avatar

didn’t our African Negro forefathers, persecute the genetically paler born individuals, as physically inferior and thus a curse upon the tribe, they were then forced to flee northward into the more sunless European climate, whereupon they grouped up with their nerdy little colourless buddies, to devise long range weaponry with which to arm themselves and head back down to the south side, for some good old fashion payback? Hence the regional skin tones.

whatthefluther's avatar

Removed by self (don’t feel like feeding trolls today)

richardhenry's avatar

The ability for your skin to be burnt by ultra-violet light is the real issue, and not that of your body temperature. The type of melanin that is produced in our skin reduces the effect of UV light, and your skin appearing more brown is simply a side effect of the presence of melanin. The benefit outweighs the cost.

Izzard's avatar

@richardhenry Yeah I think that’s basically it – the benefit of melanin protecting from UV damage outweighs the cost of absorbing more heat. I still think it would make more sense for melanin to be white or silver instead of a dark colour but – as I said – I won’t argue with evolution :)

crisw's avatar

@Jack79

“Apparently having dark skin is the result of staying in the sun, and not an evolutionary tactic.”

Actually, it’s all about evolution.

UV destroys folate in the body, and dark skin evolved, at least in part, to protect folate. On the other hand, in more northerly climes where sun strength is less, light skin allowed maximum vitamin D production.

Fyrius's avatar

I don’t think evolution had much of a say in what the colour of melanin would be… Evolution can’t change just anything, it has to work with what is physically possible to evolve. Otherwise there would probably be animals by now that could live without food and had built-in laser cannons.
Besides, if the skin of people in sunny areas were silver instead of black, everyone would be blinded all the time.

@DarkScribe
Hang on.
Anthropologists estimate that we started wearing clothes about one hundred millennia ago. Isn’t that way too recent to have affected our evolutionary history much?

DarkScribe's avatar

@Fyrius DarkScribe Hang on.

Ok, don’t forget to tell me when I can let go. (Are you doing some research on melanin?)

DarkScribe's avatar

@Fyrius Anthropologists estimate that we started wearing clothes about one hundred millennia ago. Isn’t that way too recent to have affected our evolutionary history much?

Having looked at clothing, armour, doorway heights that are only a few hundred years old, and seeing how quickly people can adapt to environment, (available food sources) no I don’t think that is too recent at all.

Fyrius's avatar

@DarkScribe
Thanks for hanging on. You can let go now.

“Having looked at clothing, armour, doorway heights that are only a few hundred years old, and seeing how quickly people can adapt to environment, (available food sources) no I don’t think that is too recent at all.”
Hang o-
(cough)
Hold it.
I don’t think this recent increase in height is really a result of human evolution, but only one of a change in nutrition. You’re right that these changes are recent – too recent. It’s documented that what used to be really tall people in as late as the mid-nineteenth century would be short compared for example to yours truly.
Recall that we’re talking about genetic changes here. There’s no way that happens in a century and a half.

In addition, you call this adapting to our environment, but I’m pretty sure our environment did not suddenly start requiring us to be tall. Our tallness might result from our new situation, but not as an adaptation.
In fact, what with doors and ceilings being adapted to the medieval standard of height, you’d think there would be an evolutionary pressure against tallness.

DarkScribe's avatar

@Fyrius but why would people evolve to become taller?

It might simply be a part of Darwin’s musings. The taller members of society got to breed more often.

There are many more “whys”.

Why are there so many more blondes in Nordic countries? Why do Inuit people succeed in surviving on a diet that is considered the epitome of poor diets? Why do people who eat at McDonald’s remain healthy. Oh, sorry – scratch that one.

Fyrius's avatar

Darwin’s musings? I don’t follow.

Anyway, most of those “why’s” have been answered. I’d like the one relevant “why” to be answered too before I stop considering it an adequate counterargument.
Or else I’d like to abandon the idea that this is really a matter of evolution.

In fact, even if they weren’t answered, what kind of weak excuse is that? There are things that haven’t been explained, therefore we don’t have to explain ourselves either? That’s completely unscientific, and self-reinforcingly counter-productive.

DarkScribe's avatar

@Fyrius _I’d like the one relevant “why” to be answered too _

You won’t get an answer, you might get some reasonable theories.

What happens when a white person spends time in the sun?

They turn black. When I am living on board my yacht I go as dark as most African, Indian people. Very dark brown. Once I reach that stage I can work shirtless in the sun all day without burning. My comment before about Melanin is the reason. When I become more tanned, my skin has more melanin. Dark skinned people have more Melanin to begin with.

It gets a little more complex than that, but in a simplified version that’s about it. You can go into the various type of UV rays (UVa, UVb, UVc etc, and the body’s melanin response to them) but it one way or another it all comes back to melanin.)

Izzard's avatar

I did a bit of research and, like @crisw up there, also realised that British people like me are pale because melanin restricts our ability to make Vitamin D through exposure to sunlight. So one way of looking at it is that as humans moved away from the fertile crescent and away from the equator, they tended to become lighter-skinned to aid with Vitamin D production (as opposed to being due to a reduced need for UV protection).

Fyrius's avatar

@DarkScribe
If I won’t get an answer, I’ll stick to my null hypothesis that this is not a good explanation. Reasonable theories hypotheses are usually the best answers available, though. But I’m not convinced yours holds much water.

I believe one of the complexities you’re omitting completely overturns your comparison.
What happens to you on your yacht obviously does not change your genes. Tan is acquired and not passed on to offspring.
But the skin of black people is innately that rich in melanin. You might turn dark-skinned when you’re in the sun long enough, and then turn back into PaleScribe when you’re back home, but black people are black even if for generations they’ve lived in the rainy, cloudy Netherlands where sunlight is a rare treat.
Black people aren’t black because they live in a sunny place. They’re black because their ancestors have lived in a sunny place for millions of years, and because people with more melanin are less liable to get cancer from the sun and more likely to get laid before they kick the bucket.

Stature is different. Stature changed over the course of at most a century and a half, for no apparent reason. And that change is most probably not a genetic one. It’s not evolution.

If we want to be sure whether people evolved to be taller or just started eating differently, we should raise a few children with the kind of diet that prevailed in the mid-nineteenth century and see how tall they become. And compare them to a control group of children of the same age that we didn’t abduct.

Just to be clear on this: I am taking your point to be that people evolved to become taller, and that the above post was supposed to back this up.

DarkScribe's avatar

@Fyrius

What we have here is a failure to communicate…

You have just agreed with me – yet are arguing?

I have just said that black people have more melanin

Dark skinned people have more Melanin to begin with.

and the rest was to illustrate the reason why. Melanin is required for safe sun exposure and they have lived in the sun for millenia.

If we want to be sure whether people evolved to be taller or just started eating differently, we should raise a few children with the kind of diet that prevailed in the mid-nineteenth century and see how tall they become.

As for this contention, there have been many groups who were raised on a mid nineteenth century diet, I am from a family who ate in that fashion. We never had packet, processed or takeaway foods while I was young. I passed six feet tall at thirteen.

Izzard's avatar

@DarkScribe “I am from a family who ate in that fashion. We never had packet, processed or takeaway foods while I was young. I passed six feet tall at thirteen.”

I think that’s what’s called ‘confirmation bias’!

DarkScribe's avatar

@Izzard I think that’s what’s called ‘confirmation bias’!

No, it is called “Fanatical Mother”. She distrusted anything that she didn’t make herself. She was an Adele Davis fan.

Fyrius's avatar

@DarkScribe
I figured as much.
Well, if the only thing you’re trying to say is that black people have more melanin and it helps them not to get skin cancer, I think we can agree.

But I did have the impression you were saying up there that people evolved to become taller in just 150 years.
@Fyrius: “Isn’t that way too recent to have affected our evolutionary history much?”
@DarkScribe: “Having looked at clothing, armour, doorway heights that are only a few hundred years old, and seeing how quickly people can adapt to environment, (available food sources) no I don’t think that is too recent at all.”
Otherwise this here was a non sequitur, because people getting taller would have nothing to do with how quickly humans can evolve.

“As for this contention, there have been many groups who were raised on a mid nineteenth century diet, I am from a family who ate in that fashion. We never had packet, processed or takeaway foods while I was young.”
I do hope that last sentence was not supposed to be your definition of a mid-nineteenth century diet. Even besides the fact that you’re defining something by what it’s not, surely you can’t assume with no questions asked that packet, processed and takeaway food are the only things that changed in our diet in the previous 150 years. And besides what people ate back then, did you also eat just as much of it, in the same relative proportions and at the same times of the day?
And even if every answer to those questions is yes, this is anecdotal evidence. If you want to know this sort of thing with any reliability, you need to get statistically robust samples, and compare them to equally statistically robust control groups, to make up for extraneous factors that might have influenced your height.

I’m not convinced.

DarkScribe's avatar

@Fyrius Otherwise this here was a non sequitur, because people getting taller would have nothing to do with how quickly humans can evolve.

The average height of an entire race increases by several inches in a few hundred years and this is not evolving?

Hmmmm.

As for diet, we ate pretty much what landowners or middle class would eat then. Fresh meat, locally grown vegetables, homemade bread etc. It might not be exact, but it was close. When I was in Scotland as a kid, I met many village people who had very little in the way of lifestyle change from their great. great grandparents day. The same in southern France and Northern Italy.

There is no way that diet accounts for it, there would be a disparity between those nations who have modern diet and those who experienced little change.

As I have said several time “several hundred years” you might realise that I am not referring specifically to the nineteenth century. The armour and building doorways that I am referring to are from the middle ages, not just a hundred or so years ago. The growth was well established by the eighteenth century, not starting in the nineteenth. It did continue, but that is incidental if you are looking at diet for a cause.

As a child I lived in a village called East Meon, in Hampshire UK in a Manor house that was built in the fourteenth century. That is where I first saw doorways that you had to stoop to go through, and in nearby castles, I saw armour that would fit a modern child.

Fyrius's avatar

So you were saying that after all.

I can only assume the “hmmmm” is supposed to be sarcastic, because nothing else in your post implies you’ve given this idea much thought.

1. Do you even know the first things about how evolution actually works? Evolution doesn’t happen all by itself. There needs to be a driving force so that taller people get laid more before they die. I have not been convinced that any such force exists in our case, beyond perhaps women liking tall guys.
And as for that one potential exception: contrariwise, men tend to like shorter women. And considering that men usually had the last word in who screwed whom, that should have been a much more influential force towards collectively becoming short, actually.

2. Again, 150 years is nothing. That’s just some five generations. It takes hundreds of generations for any kind of evolution to manifest itself. That alone would be enough to definitively rule out the possibility of an evolutionary explanation.

3. Evolution does not affect an entire race all at once. It’s every individual, or even ever gene, for itself. Thus evolution shapes itself like the branches of a tree more than like the steps of a stairway.
An increase across the entire species during the same period disproves an evolutionary explanation and argues for an explanation in terms of changing nutrition habits, as a result of industrialisation or some other development that changes pretty much the entire planet at the same time.

In conclusion: No, absolutely not.

DarkScribe's avatar

@Fyrius Again, 150 years is nothing.

You don’t read posts before responding – do you?

Little point in this.

Fyrius's avatar

Am I supposed to foresee you’re going to edit your post after I’ve started replying? You responded to obsolete quotes of mine too, up there.

It doesn’t matter. Even 500 years is still nothing on the kind of scale that evolution operates on.

Moreover, isn’t it curious how gradual this increase seems to be? If what you say is true, medieval people were shorter than 19th century people, who were shorter than us. You’re saying this is evolution. That means medieval people were genetically shorter than 19th century people, who were genetically shorter than us.
How is that supposed to work?

If this difference in height is innate, that means there would have to be at least two independent genetic changes that improve growth, one of which kicked in between the Middle Ages and the 19th century and the other one of which reported for duty between then and now. There would need to have been two genetic revolution periods in between our three data points when there were tall people with the new genes and short people with the old ones.
Otherwise, if the people of the 19th century had the same height genes as the medieval folks, or the same as you and me, they would all have the same height of the medieval people or us respectively. Which is not the case.

That makes it an ugly explanation because it requires us to just assume (at least) two genetic configurations existed, but it also makes it a plainly absurd one because it faces the exact same “150 years is nothing” problem again, plus an additional “350 years is also nothing” problem on the other side.

By contrast, if it’s due to new nutrition habits, a gradual change could be due to more and more innovations like the discovery of germs, the invention of things like pasteurisation, better knowledge of how food affects the human body, et cetera. Not to mention more and more food becoming available.

That makes four good reasons total why this has not been an evolution. Two of them methodologically compelling and two of them factually insurmountable.
Ready to reconsider yet?

DarkScribe's avatar

@Fyrius That makes four good reasons total why this has not been an evolution.

I have no idea what you are talking about. I suspect that you don’t either.

”...an evolution”???

Talk to me about when I am beginning a slide into senility. That would hopefully be in about sixty years or so. I might agree with you then.

Fyrius's avatar

Oh, for crying out loud.

evolution (plural evolutions)
“1. (general) A gradual process of development, formation, or growth, esp. one leading to a more advanced or complex form.”
http://en.wiktionary.org/wiki/evolution

In the scientific sense, a single adaptation that has been brought about by the evolutionary process.

Your poor vocabulary and refusal to consult a dictionary aside, I do believe I have thoroughly debunked your outlandish hypothesis. Meanwhile, you have shown not to know the first things of the evolutionary process on which your own explanation fundamentally relies, and your only attempt to refute any of my objections has backfired on you by doubling the force of the objection and adding a new one.
If in the face of all of this you still can’t conceive of yourself agreeing with me before losing your wits altogether, I can only assume you haven’t understood a single word I said.

I suggest you spend those sixty years reading up on evolutionary biology and the general scientific modus operandi. You’ll have a lot to learn about both if you want to talk about this sort of subject but can’t follow what I wrote in this thread.

You disappoint me.

Girl_Powered's avatar

@Fyrius

When I was in school we were taught that the universal change in height, the change in hearing frequency levels and the change in peripheral vision were all examples of evolution in action, recent evolution as a part of result natural selection as well as genetic drift. This is also represented in some fairly prominent museums and textbooks. Are you saying that they are all wrong?

brownlemur's avatar

@Fyrius: Change in height across the last few centuries is really more of an issue of modern nutrition. Turkana Boy and others are of so-called modern stature, so there has not been an “evolution” of height in recent times, as is my understanding.

I don’t know enough about the changes in hearing frequencies and changes in peripheral vision to discuss those topics at length with you, but I am curious. It’s not really possible to extrapolate what the hearing frequencies of early hominins would have been, since (1) they aren’t around to test, and (2) soft tissue and ossicles of the ear don’t generally fossilize, so we can’t run any cool tests a la von Bekesy. What I do know about the range of human hearing is that it spans from about 20 hertz to 20 kilohertz (but generally most sensitive to sounds between 1 and 4 kilohertz).

Cool factoid: humans can hear at such soft sound intensities (decibels, or dB SPL), that the lowest intensity we can detect is just a hair louder than the sound given off by Brownian Motion.

Girl_Powered's avatar

@brownlemur: Change in height across the last few centuries is really more of an issue of modern nutrition

Yes, that is what we were taught, that it was an evolutionary change caused by the increase in food availability, not type of diet. That when mankind was often hungry stature was kept smaller, and that once food was reliably available we grew taller. It was regarded as evolution as it caused a change in our DNA structure.

Izzard's avatar

@Girl_Powered They taught you that once food was reliably available humans grew taller and this changed their DNA structure…and that’s “evolution”?

I find it really worrying that you were taught that. You know better now, though, right?

Izzard's avatar

I don’t mind that my Fluther became a debate about height/evolution – it’s interesting :)

OK – I’ll put my neck on the line…this is how I see it:

In modern times our potential to grow tall is less restricted by disease, poor diet/nutrition that it was historically. I suspect if you identified someone from hundreds of years ago who only reached 5 feet in height as an adult, went back in a time machine to their birth and brought them into the modern world (e.g. Europe/USA) to grow up, they’d grow to be a taller adult, due to better medicine, better nutrition and better hygiene. (I admit I base that on nothing more than my own speculation.) What do you think?

Girl_Powered's avatar

@Izzard

You suggestion is a little too simplistic if you think about it carefully. It must be a genetic change based on general population nutrition levels or all wealthy people would be much taller than the rest of the population. The aristocracy can trace a thousand years or more of wealth and unlimited healthy food – why aren’t they taller? We were taught that the change in nutrition changed our genetics, our DNA and that must be so, or else as I have pointed out, the wealthy would be taller much sooner.

Fyrius's avatar

@Girl_Powered
What changes were these exactly, and when did they occur?

And if you wish to contend that these things evolved, how do you refute the four objections I gave above (apparent lack of evolutionary pressure, apparent graduality, uniform change across the entire species at the same time, preposterously short time span)?

@brownlemur
Thank you. That’s what I was trying to say.

@Girl_Powered: “The aristocracy can trace a thousand years or more of wealth and unlimited healthy food – why aren’t they taller?”
Aha! A very good point. But not an argument for your cause, I’m afraid.

Who’s to say the genes of the entire population would change all together at once, and not just the ones of the aristocrats? As I pointed out, evolution is tree-shaped; it’s every organism for itself, or at most every family for itself. Evolution is not something that happens to an entire species in the same way. That’s how one species can split up into different life forms.
So, if this alleged evolutionary change really happened as a result of getting more food, as you suggest, what we would expect is that rich people evolve to accomodate for getting more food, while poor people remain the way they are. The rich people should be taller than the poor people.
In other words, this objection applies to the nutrition-and-medicine explanation no more than it applies to the evolutionary explanation.

My guess would be that in the past, aristocrats were taller than peasants. And precisely because this has not been a genetic change, the effects are no longer visible now that most people have enough to eat and then some.

As another side note, though, it would be simplistic to summarise all the changes in our diet over the past centuries as “getting more to eat”. Obviously, we also eat different things now, in different relative proportions, at different times of the day, and during different times of our lives. We got the Food Pyramid, we invented refrigerators, we got health education in schools, we got food labels telling us exactly what nutrients are in what food. All of these things could affect our stature in ways that the aristocrats’ diet might not have affected theirs.

walterallenhaxton's avatar

No. What does biology have to do with making sense? It is all about what works.

Girl_Powered's avatar

@Fyrius “And if you wish to contend that these things evolved, how do you refute the four objections I gave above”

I don’t, I don’t find them valid, they don’t need refuting. I will trust several different science texts, several different professors trained in both biology and history, the British Museum and Charles Darwin before considering your contradictory theory.

“Aha! A very good point. But not an argument for your cause, I’m afraid”

Don’t be afraid, I am not as I feel that it is a more than adequate argument.

“My guess would be that in the past, aristocrats were taller than peasants. And precisely because this has not been a genetic change, the effects are no longer visible now that most people have enough to eat and then some.”

Precisely. Your guess.

The country is riddled with paintings, literature, and the actual clothing that many of them wore. You really think that nobody would notice if they were taller than others? In many cases they were smaller, possibly because there was less new blood entering a rather limited ‘Royal’ gene pool.

We do not agree. I will stick to my more than a little expensive tertiary education and ignore your determined and very closed minded ‘guesses’ thank you.

Please don’t bother beginning an endless series of lectures bases on guesswork as you have with some others, unlike some of those who ‘play ping pong post’ with you, I am not interested in responding to a plainly biased person. We disagree, just leave it at that.

walterallenhaxton's avatar

Regulating the production of vitamin D is obviously important to the survival of human beings. Too little and you have problems as well as too much. That is what skin color is about.

Fyrius's avatar

@Girl_Powered
If you want me to agree to disagree and stop talking to you, you would do well not to slap me in the face with a glove in the same post.

“I don’t, I don’t find them valid, they don’t need refuting.”
What the deuce are you saying? Of course they need refuting, especially if they’re invalid.
You need to explain to us why they’re invalid. That’s what “refuting” means.

Unless you find my arguments invalid for no reason at all, refuting them should only be a matter of speaking your mind.

“I will trust several different science texts, several different professors trained in both biology and history, the British Museum and Charles Darwin before considering your contradictory theory.”
Then at the very least, refute me with reference to them.
I doubt they even say what you think they say. PROVE ME WRONG!

As for your taller aristocrat argument: how do you explain the fact that they are not taller than everyone else? Like you said, they’ve been eating well for centuries more than the rest of us, and if eating well triggered an evolution to become taller, why aren’t the (former) aristocrats taller than the rest of us?
I explained how this is not a problem to my explanation. Our eating habits changed in ways that could affect our stature in ways that they could not have affected those of the aristocrats of yore.
Here’s a hint: I think you can probably adapt the same explanation to support your own position. Now you give it a try.

“I will stick to my more than a little expensive tertiary education and ignore your determined and very closed minded ‘guesses’ thank you.

Please don’t bother beginning an endless series of lectures bases on guesswork as you have with some others, unlike some of those who ‘play ping pong post’ with you, I am not interested in responding to a plainly biased person.”
How dare you?
If you accuse me of closed-mindedness and bias, I demand that you tell me what you base this judgement on. In PM, if you must.

How outrageous you are.
You have evaded and dismissed my arguments for no given reason, replied to a meticulous explanation why your argument doesn’t hold with no more than “yes it does”, referred to authorities (who I have been given no reason to believe are even on your side) in lieu of motivating your views, and then went on to call me biased.
Well, madam, I for one defend the positions I take. I handle criticism on my views by actually addressing it and evaluating whether it holds water or not, I explicitly refute counter-arguments when I can, and I do change my mind when I cannot. I believe what I believe for explicit reasons, reasons I share with the rest of the world to comment on and attack. I purposely put my beliefs on the line to test whether I should keep them.
But I’m also critical thinker, and in order to persuade me, you’ll need solid arguments that I cannot find fatal flaws in. And if other people fail to attack my beliefs in ways I cannot parry, I will not change my mind for what I have good reasons to believe are not to good reasons.

Do not mistake scepticism for closed-mindedness. They are very different.

DarkScribe's avatar

@Fyrius

How rude!

She won’t play by your rules!

Never mind, you can argue with me. I won’t take any more notice than she seems to, but at least I’ll play the ping pong post game with you.

As for your taller aristocrat argument: how do you explain the fact that they are not taller than everyone else?

BTW, I thought that she explained it pretty well. What didn’t you understand? Tell me and I’ll try to explain it for you.

Girl_Powered's avatar

@DarkScribe

He is one of those people who don’t look at responses before replying. I think that you are wasting your time, but it is your time to waste. I will not respond to him again but am quite willing to discuss things with anyone who actually registers what is said to them. He either doesn’t understand evolution or is conveniently ignoring aspects of it when it suits him.

As for the original question, when clothed, as you pointed out, skin color as far as reflecting or absorbing heat is quite different. Few races, even tropical do not clothe themselves. There could be other aspects too, but I feel that as most species develop in a way that is protective, there will always be a reason for things, even if not immediately apparent.

Are you Australian born?

walterallenhaxton's avatar

@Girl_Powered The color of the skin has nothing to do about it. If you had any knowledge on the subject you would kno that. It is what gives skin color that it is all about not the color. The colorant keeps the body from producing too much vitamin D. That is all. It is all about healthy people being favored for reproduction over unhealthy ones.

Girl_Powered's avatar

@walterallenhaxton

“The color of the skin has nothing to do about it. If you had any knowledge on the subject you would kno that. It is what gives skin color that it is all about not the color”

Would you care to rewrite that? It doesn’t make sense, none at all.

As for dark skin being primarily to avoid overdosing on vitamin D, that is as funny as anything that I have read or heard for weeks. Why do Inuits have dark skin? You know, land of the polar night/midnight sun etc.

Fyrius's avatar

@DarkScribe, @Girl_Powered
Fine, have it your way. I’m out of this thread.
I hope for the sake of your own information that someone else with any evolutionary and general academic know-how will drop by and present you the flaws of your explanation on a silver platter like I have done, and that you’ll consider actually giving them a chance like you haven’t done with me.

“How rude!

She won’t play by your rules!”
“My rules” are the internationally accepted rules of (scientific) debate. One person gives arguments for their view, the opponent then tries to refute those and gives arguments of their own. We don’t ignore other people’s arguments, we’re open to the possibility that we’re wrong, and if the facts are overwhelmingly against us, we abandon our indefensible position.
Following these rules is a requirement for any kind of civilised debate. And you both violate them time and time again.

“He is one of those people who don’t look at responses before replying.”
“anyone who actually registers what is said to them.”
“He either doesn’t understand evolution or is conveniently ignoring aspects of it when it suits him.”
All right, that’s enough.
You must be a troll. Surely you can’t actually have things this backwards. Surely you can’t be this much of a hypocrite.
I hereby mark you on my list of “people to ignore”. Congratulations, it’s not easy to get me to close my mind to anyone. It’s like your accusations of not listening to you are a self-fulfilling prophecy.

Oh, wait. I shouldn’t get so hung up on my own rules. I should try playing the game by your rules too. All right, here goes.

I should point out that you have no more than a pop culture understanding of evolution, where the entire species goes through the same phases at the same time. Any high school child who doesn’t fail biology class would know better.
You know even less of the scientific method and of how to put up an argument. You’ve proven completely impervious to reason. You’re closed-minded and bent on keeping an explanation despite being completely unable to defend it.
You make the impression of two irrational, academically incompetent dunderheads whom their undoubtedly expensive education taught nothing at all, and who can only handle being proven wrong by plugging their ears and shouting they’re right. You’re like savage beasts that spit venom when cornered. Irrationalists like you are the bane of humanity. You’re pathetic and despicable.
Oh, and you’re racist. Now excuse me while I utterly refuse to justify why the deuce I would say that. Who needs criticism to be constructive? We’re just here to call each other names, after all.

How did I do?
Don’t bother answering that, I won’t be here to read it any more.

Girl_Powered's avatar

@DarkScribe I think that you have offended him. He seems upset.

But then when he says “Congratulations, it’s not easy to get me to close my mind to anyone.” it does make it difficult for me to keep a straight face. When he says “We don’t ignore other people’s arguments, we’re open to the possibility that we’re wrong,” I can no longer keep a straight face, I burst out laughing.

Still, maybe someone should start him here. http://en.wikipedia.org/wiki/Evolution

I know Wikipedia isn’t the best of resources, but in his case it has to be better than what he has.

walterallenhaxton's avatar

@Girl_Powered Light skin is good in the north/south and a bad thing to have at the equator. Dark skin can lead to serious vitamin d deficiencies in the north/south.
I imagine that your Inuit people eat a great deal of meat containing vitamin-d.
Nothing in biology makes sense. It just furthers survival.
People make vitamin-d when exposed to the sun. Pigment is a sun screen.

Izzard's avatar

@Girl_Powered “Why do Inuits have dark skin?” Because they’re not really “from” where they now reside – they’ve only been there about 5,000 years.

mattbrowne's avatar

Evolution created time-tested species and races.

walterallenhaxton's avatar

@mattbrowne Not exactly. Creates not created. Not exactly that either. I don’t think that English has a word that includes both concepts.

brownlemur's avatar

@walterallenhaxton don’t you mean, “Nothing in Biology Makes Sense Except in the Light of Evolution?” (Theodosius Dobzhansky)

walterallenhaxton's avatar

@brownlemur The origins of life are not evolutionary in nature. They have to do with chemistry both of the elements and of solid objects as well as large numbers and the conditions necessary for order to survive long enough to be combined into larger structures.
Evolution is life’s response to change so the change agents are most important as well.

mattbrowne's avatar

@walterallenhaxton – The term evolution has a very broad sense. We can speak of the evolution of the elements, also called nucleosynthesis, or the the evolution of molecules. The origins of life cannot be explain by Darwinian processes. At the moment we have little clue how DNA and proteins evolved from simpler molecules such as amino acids. We don’t know what really happened before the first cell.

walterallenhaxton's avatar

@mattbrowne That is because natural selection did not exist at that time. The molecules were organized units but they had not become to the organized process that is life yet. So I do not use evolution as a term before the organized process begins. It is the process that evolves. Not complex molecules.

We do know quite a bit. The thing is that the pieces of the puzzle are not put together. There are several ways that it could work I suspect and just one way that it happened. I think it was just chance that it happened the way that it did. Once it had happened then the other ways were no longer possible. Life was using them for food.

I don’t know much about it but I remember something about left and right sugars and there being no reason that they should not be the other way around except that they were the way they were.

Have you heard of the posibility of long molecules forming on ice? I did mention the chemistry of solids. We don’t know all about it.

mattbrowne's avatar

We might know some aspects of what happened before the first cell, but there’s nothing conclusive. Long molecules forming on ice? No, sounds interesting. I read a few articles on black smokers, see

http://en.wikipedia.org/wiki/Iron-sulfur_world_theory

Yetanotheruser's avatar

One of the fathers of the “African Genesis” theory (Ihis name escapes me but the book I read was published in the sixties) has stated that albinism, or the lack of melanin in the skin, would be considered a negative trait in the hot sunny tropics; but the same lack of melanin would allow the body to absorb the rarer vitamin-D-filled rays of the more temperate or even arctic sun.

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