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The evolution of the nose: why is the human hooter so big? - space air conditioner

by:HICOOL     2021-10-11
The evolution of the nose: why is the human hooter so big?  -  space air conditioner
This is an evolutionary mystery, as simple as the nose on your face.
Why do our ancestors form a prominent nose when most primates have flat nasal plugs? New research suggests that our unusual nose may only be formed as a by-product.
Other products of more important changes in our facial structure-although other researchers insist that some people's noses are shaped directly by natural selection.
One of the many functions of the nose and nasal cavity is to act as a "air conditioner ".
Together they make sure that the air the animals breathe is warm and humid enough to avoid damaging the fragile lining of the lungs.
Nishimura Wu of Kyoto University in Japan and his colleagues believe that the human nose is not performing well in this work.
They scanned the noses and nasal passages of 6 volunteers, 4 chimpanzees and 6 macaques.
They then used a computer to simulate the flow of the inhaled air through the nasal passage.
Finally, they calculated the adjustment efficiency of these flow modes for three different air types: cold and dry, hot and dry, warm and wet.
The results showed that the nasal passages of chimpanzees and macaques were more effective in regulating the intake of air than our nasal passages.
In fact, even if researchers manipulate computers artificially
The resulting human nose looks more like the flat nose of a chimpanzee
Adjustment performance has not improved.
"It shows that our prominent nose contributes very little to the air --
Conditioning of the nose and nasal cavity, "said Xicun.
He thinks that we may have only a chance to get a prominent nose and a bad nose.
2 to 3 million years ago, the human skull experienced a dramatic reorganization, and the real human being emerged from our kind.
In order to make room, the gray brain becomes relatively small-it is possible for the nose and nasal cavity to be forced into the current shape to adapt to these changes.
Fortunately, at the time of the real human first appearance, climate fluctuations in Africa made good air conditioning crucial, and other parts of human aviation have changed.
This may make up for any inefficiency of the nose and nasal cavity, enabling humans to fully regulate the air they breathe in.
In particular, the throat area-which is much longer in humans than in other primates-may have begun to lengthen at this time.
Our long swallowing is often related to our ability to speak, but Xicun says it also plays an important role in regulating the intake of air.
Despite the new findings, Todd Laiz of the University of Rockhampton in the UK said that we should not give up the idea that the nose adapts to the climate in which the owner lives.
"There is a general trend for people in the tropics, that is, the nostrils are wide," he said . ".
"On the other hand, the European aperture is smaller, which is considered an adaptation to living in a cold climate.
The idea is that narrow nostrils produce more turbulence in the air sucked in, which increases the level of heat and moisture exchange between the air and the tissue that covers the nasal wall.
The Neanderthals are clearly a clear exception to this rule-they live in cold Europe but have a big nose.
Bouterre and his colleagues believe that this may be due to the fact that the Neanderthals evolved and adapted in relatively warm and humid conditions before they later entered Europe.
"If you don't think [Neanderthals]were cold-
"After adjustment, the shape of the aperture is not confusing because it is only inherited from their common ancestor," said Rae . ".
Journal of reference: PLoS Computational Biology1371/journal. pcbi. 1004807
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