WEBVTT - BrainStuff Classics: Are Humans Still Evolving?

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<v Speaker 1>Welcome to brain Stuff production of I Heart Radio. Hey

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<v Speaker 1>brain Stuff. I'm Lauren vog Obam and this is a

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<v Speaker 1>classic episode from our archives and from our prior host,

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<v Speaker 1>Christian Sager. Today's topic may or may not have been

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<v Speaker 1>inspired by his pervasive love of the X Men. Are

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<v Speaker 1>humans still evolving? Welcome to brain Stuff. I hope you

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<v Speaker 1>survived the experience. I'm Christian Sager, and I'm the best

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<v Speaker 1>there is at what I do. And today I'm going

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<v Speaker 1>to tell you how human beings are still evolving. But

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<v Speaker 1>into what I mean, like, where are cool mutant powers

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<v Speaker 1>that cause fear and hate in those were sworn to protect?

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<v Speaker 1>Where's my organic steel skin or my optic I beams? Well,

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<v Speaker 1>contrary to some professor's assertions, evolution does not leap forward.

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<v Speaker 1>Most experts agree that to give rise to a new

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<v Speaker 1>species like mutants, we needs some kind of geographic isolation

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<v Speaker 1>from other humans. Otherwise, cross breeding makes it less likely

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<v Speaker 1>that mutations will be established in our gene pool, and

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<v Speaker 1>with a densely packed planet full of planes and cars,

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<v Speaker 1>it's highly unlikely we're going to find that kind of seclusion.

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<v Speaker 1>Think of it this way. Genetic mutations are only passed

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<v Speaker 1>down if they afford us some kind of benefit through

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<v Speaker 1>natural selection, that doesn't mean we've stopped evolving. In fact,

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<v Speaker 1>over time, we've already developed powers well sort of like

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<v Speaker 1>how about the power to drink milk or fight disease?

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<v Speaker 1>Because these, along with tiny teeth and small brains, are

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<v Speaker 1>the mutant powers most of us are born with. Let's

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<v Speaker 1>start with the milk powers, otherwise known as lactase persistence. See.

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<v Speaker 1>Milk contains a sugar called lactose, and people need an

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<v Speaker 1>enzyme called lactase to digest it. Most manimals lose this

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<v Speaker 1>enzyme after they stop breastfeeding, but certain human populations have

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<v Speaker 1>evolved so their lactase persists, allowing the digestion of milk.

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<v Speaker 1>This was nutritionally advantageous, especially when we domesticated cows and goats.

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<v Speaker 1>Now this genetic mutation is carried by more than of

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<v Speaker 1>people of Northern European descent. Researchers have also found signs

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<v Speaker 1>of another set of human mutations that were devoted to

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<v Speaker 1>fighting off infectious diseases. Afflictions like malaria or tuberculosis used

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<v Speaker 1>to mean bang, you're dead, but over the last forty

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<v Speaker 1>thousand years we evolve to be more resistant to disease

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<v Speaker 1>because our ancestors happen to have the right genes to

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<v Speaker 1>fight off these viruses and bacteria, our mutant power to

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<v Speaker 1>resist disease may not last much longer. However, as we

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<v Speaker 1>become more dependent on medications for survival, our immune systems

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<v Speaker 1>will slowly weaken. The more that pathogens are defeated by drugs,

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<v Speaker 1>the less our body will need the internal functions to

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<v Speaker 1>withstand them. This is not to say that modern medicine

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<v Speaker 1>or vaccinations are bad, because without them we'd see a

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<v Speaker 1>huge increase in disease related death, which I'm going to

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<v Speaker 1>assume you also think is a bad thing. So maybe

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<v Speaker 1>milk powers or anti disease genes aren't what you were

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<v Speaker 1>hoping for. What about smaller jaws and less teeth. Our

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<v Speaker 1>ancestors had huge jaws so they could chew on tough

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<v Speaker 1>foods like roots and nuts, and wisdom teeth helped them

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<v Speaker 1>replace their worn down pearly whites from tearing meat apart

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<v Speaker 1>with no quarter asked and none given. But today our

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<v Speaker 1>food is softer, easier to chew, and we use utensils

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<v Speaker 1>to cut the portions we put into our mouths. Consequently,

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<v Speaker 1>our jaws got smaller, our teeth are half the size

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<v Speaker 1>they used to be, and we don't really need wisdom

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<v Speaker 1>teeth anymore. They're already gone in some ethnic groups, and

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<v Speaker 1>many predict they'll disappear entirely. Now. I don't need telepathy

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<v Speaker 1>to know that you think these are really lame powers.

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<v Speaker 1>How about one more mutation. Did you know that our

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<v Speaker 1>brains have been shrinking for the last thirty thousand years.

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<v Speaker 1>Some researchers think this means we're getting dumber, because the

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<v Speaker 1>safety of modern society doesn't require intelligence for survival, but

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<v Speaker 1>others argue that smaller brains just mean they're more efficient.

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<v Speaker 1>Maybe our wiring up there takes up less room because

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<v Speaker 1>it's faster, like when you get a newer, smaller phone

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<v Speaker 1>that has better RAM than your old one. Hopefully, as

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<v Speaker 1>my brain reaches peak efficiency, I'll be able to focus

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<v Speaker 1>the totality of my psyche into some kind of weapon.

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<v Speaker 1>Today's episode was written by Christian and produced by Tyler Clang.

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<v Speaker 1>Brain Stuff is a production of I Heart Radio's How

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<v Speaker 1>Stuff Works. If you miss Christian and want to hear

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<v Speaker 1>more about the X Men, check out his podcast about

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<v Speaker 1>the culture of pop culture, super Context and For more

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<v Speaker 1>on this and lots of other topics, visit our home

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<v Speaker 1>planet hows toff works dot com plus for more. Podcast

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<v Speaker 1>for my heart Radio, visit the heart Radio app, Apple Podcasts,

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<v Speaker 1>or wherever you listen to your favorite shows. H