Are Humans Still Evolving?
141.2 هزار بار بازدید -
9 سال پیش
-
We may not have mutant
We may not have mutant powers like the X-Men, but natural selection is still changing humanity… for the better.
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Welcome to BrainStuff. Hope you survive the experience. Today I’m going to tell you how human beings are still evolving.
But into what? I mean, like where are our cool mutant powers that cause fear and hate in those we’re sworn to protect? Where’s my organic steel skin? Or my optic eye-beams? When can I join the X-Men?
Well, contrary to the assertions of a certain bald professor, evolution does not “leap forward.” Most experts agree that to give rise to a new species (like mutants) we’d need some kind of geographic isolation from other humans. Otherwise, cross-breeding makes it less likely that mutations will be established in our gene pool. And with a densely-packed planet full of planes and cars it’s highly unlikely we’re going to find that kind of seclusion.
Think of it this way: genetic mutations are only passed down if they afford us some kind of benefit through natural selection.
That doesn’t mean we have stopped evolving. In fact, over time we’ve already developed powers… sort of… Like how about the power to… da da da dun… drink milk? Or fight disease? Or have tiny teeth? Because these are the mutant powers most of us are born with.
Let’s start with the milk powers, otherwise known as “lactase persistence.” Milk contains a sugar called lactose and people need an enzyme called lactase to digest it. Most mammals lose this enzyme after they stop breast feeding.
But certain human populations have evolved so their lactase production persists, allowing the digestion of milk. This was nutritionally advantageous, especially when we started domesticating cows and goats. Now this genetic mutation is carried by more than 95 percent of people of Northern European descent.
Researchers have also found signs of another set of human mutations that were devoted to fighting off infectious diseases. Afflictions like malaria or tuberculosis used to mean “Bang. You’re dead.”
But over the last 40,000 years we evolved to be more resistant to disease because our ancestors happened to have the right genes to fight off viruses and bacteria.
Our mutant power to resist disease may not last much longer however. As we become more dependent on medications for survival, our immune systems will slowly weaken. The more that pathogens are defeated by drugs, the less our body will need the internal functions to withstand them.
This isn’t to say that modern medicine or vaccinations are bad, because y’know… without them we’d see a huge increase in disease-related death.
So maybe milk powers or anti-disease genes aren’t what you were hoping for. What about smaller jaws and less teeth? Our ancestors had huge jaws so they could chew on tough foods like roots and nuts. And wisdom teeth helped them replace their worn down pearly whites from tearing meat apart like wild animals.
But today our food is softer. It’s easier to chew and we use utensils to cut the portions we put into our mouths. Consequently, our jaws got smaller, our teeth are half the size they used to be and we don’t really need wisdom teeth anymore. They’re already gone in some ethnic groups and many predict they’ll disappear entirely.
I don’t need telepathy to know that you think these are really lame powers. We have evolved mutations, just not the ones we dream about from comics or the big screen.
SOURCES:
http://www.npr.org/2013/09/27/2268378...
http://mentalfloss.com/article/30795/...
http://io9.com/5906603/new-research-d...
http://www.huffingtonpost.com/2014/05...
http://listverse.com/2012/11/26/top-1...
http://news.nationalgeographic.com/ne...
Learn more at HowStuffWorks.com:
http://science.howstuffworks.com/life...
Share on Facebook: http://goo.gl/6JIKdW
Share on Twitter: http://goo.gl/ewfcTz
Subscribe: http://goo.gl/ZYI7Gt
Visit our site: http://www.brainstuffshow.com
Welcome to BrainStuff. Hope you survive the experience. Today I’m going to tell you how human beings are still evolving.
But into what? I mean, like where are our cool mutant powers that cause fear and hate in those we’re sworn to protect? Where’s my organic steel skin? Or my optic eye-beams? When can I join the X-Men?
Well, contrary to the assertions of a certain bald professor, evolution does not “leap forward.” Most experts agree that to give rise to a new species (like mutants) we’d need some kind of geographic isolation from other humans. Otherwise, cross-breeding makes it less likely that mutations will be established in our gene pool. And with a densely-packed planet full of planes and cars it’s highly unlikely we’re going to find that kind of seclusion.
Think of it this way: genetic mutations are only passed down if they afford us some kind of benefit through natural selection.
That doesn’t mean we have stopped evolving. In fact, over time we’ve already developed powers… sort of… Like how about the power to… da da da dun… drink milk? Or fight disease? Or have tiny teeth? Because these are the mutant powers most of us are born with.
Let’s start with the milk powers, otherwise known as “lactase persistence.” Milk contains a sugar called lactose and people need an enzyme called lactase to digest it. Most mammals lose this enzyme after they stop breast feeding.
But certain human populations have evolved so their lactase production persists, allowing the digestion of milk. This was nutritionally advantageous, especially when we started domesticating cows and goats. Now this genetic mutation is carried by more than 95 percent of people of Northern European descent.
Researchers have also found signs of another set of human mutations that were devoted to fighting off infectious diseases. Afflictions like malaria or tuberculosis used to mean “Bang. You’re dead.”
But over the last 40,000 years we evolved to be more resistant to disease because our ancestors happened to have the right genes to fight off viruses and bacteria.
Our mutant power to resist disease may not last much longer however. As we become more dependent on medications for survival, our immune systems will slowly weaken. The more that pathogens are defeated by drugs, the less our body will need the internal functions to withstand them.
This isn’t to say that modern medicine or vaccinations are bad, because y’know… without them we’d see a huge increase in disease-related death.
So maybe milk powers or anti-disease genes aren’t what you were hoping for. What about smaller jaws and less teeth? Our ancestors had huge jaws so they could chew on tough foods like roots and nuts. And wisdom teeth helped them replace their worn down pearly whites from tearing meat apart like wild animals.
But today our food is softer. It’s easier to chew and we use utensils to cut the portions we put into our mouths. Consequently, our jaws got smaller, our teeth are half the size they used to be and we don’t really need wisdom teeth anymore. They’re already gone in some ethnic groups and many predict they’ll disappear entirely.
I don’t need telepathy to know that you think these are really lame powers. We have evolved mutations, just not the ones we dream about from comics or the big screen.
SOURCES:
http://www.npr.org/2013/09/27/2268378...
http://mentalfloss.com/article/30795/...
http://io9.com/5906603/new-research-d...
http://www.huffingtonpost.com/2014/05...
http://listverse.com/2012/11/26/top-1...
http://news.nationalgeographic.com/ne...
9 سال پیش
در تاریخ 1393/12/21 منتشر شده
است.
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