Where is the fur? yeah, particularly on my shiny old head!
Evolution Gap - Where's the Fur?
by shadow 87 Replies latest watchtower bible
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cofty
..models that suggest humans started walking upright as a means to cool off aren’t looking at the whole picture because in addition to the metabolic heat generated, the cooling effect gained in losing body hair would be much more profound in a person walking upright, than would be the case for one who remained crouching.
Thus, they argue, it was only after hominins started walking upright that they began losing their fur, though they do agree that the latter change came about as a means of keeping cooler.
Read more at: http://phys.org/news/2011-12-early-humans-lost-fur-bipedalism.html#jCp
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cofty
Shadow - Of course it would have taken you 30 seconds to find that study yourself if you had actually been interested in the answer rather than yet another failed "gotcha".
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shadow
Yes, I read it. How about we try to keep this cordial?
Would you be gracious enough to write in layman's terms what the steps were that led to the loss of fur?
They left the trees and then started walking upright and were better off without fur, at least after they gained enough ability to sweat? Please correct and elaborate
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shadow
and again . . . . it's not an answer
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cofty
Here click this link and read the whole paper by Ruxton & Wilkinson at PNAS...
Avoidance of overheating and selection for both hair loss and bipedality in hominins..
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cofty
See this paragraph in particular..
Specifically, our model predicts that once hair loss and sweating ability have evolved to near-modern human levels, a hominin could thermoregulate even under hot, sunny conditions and even when involved in something as energetically demanding as brisk walking. Further, our calculations make predictions as to how the evolution of such hair loss and sweating ability might be linked to daily behavioral patterns. Specifically, it is clear from the extremes of hairiness that we simulated that progressive hair loss (in the absence of specialist adaptations to maximize sweating ability) would have led to even greater risk of overheating in the heat of the day (compared with a hairier individual), but would have made it easier to have been active nearer dusk and dawn. This could have provided selection pressure for hair loss, combined with behavioral adaptations such that long-distance travel under hot, sunny conditions was constrained to occur only early and late in the day. Once hair loss and sweating ability have evolved increasingly toward near-modern human levels, this temporal restriction would have progressively decreased, until eventually such exercise was even possible (providing sufficient water was available to allow replenishment of reserves) in the hottest part of the day.
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shadow
Ok, I've read the whole thing. Did you actually read the whole thing? You refer to this article as "facts"???
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cofty
Yes and yes.
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shadow
I'll try to post my critique of this article and whether it merits being called "fact" tomorrow