BrainStuff Classics: Are Humans Still Evolving?

to tell you how human beings are still evolving. But into what I mean, like, where are cool mutant powers that cause fear and hate in those were sworn to protect? Where's my organic steel skin or my optic I beams? Well, contrary to some professor's assertions, evolution does not leap forward. Most experts agree that to give rise to a new species like mutants, we needs 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've stopped evolving. In fact, over time, we've already developed powers well sort of like how about the power to drink milk or fight disease? Because these, along with tiny teeth and small brains, are the mutant powers most of us are born with. Let's start with the milk powers, otherwise known as lactase persistence. See. Milk contains a sugar called lactose, and people need an

enzyme called lactase to digest it. Most manimals lose this enzyme after they stop breastfeeding, but certain human populations have evolved so their lactase persists, allowing the digestion of milk. This was nutritionally advantageous, especially when we domesticated cows and goats. Now this genetic mutation is carried by more than 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 forty thousand years we evolve to be more resistant to disease because our ancestors happen to have the right genes to fight off these 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 is not to say that modern medicine or vaccinations are bad, because without them we'd see a huge increase in disease related death, which I'm going to assume you also think is a bad thing. 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 with no quarter asked and none given. But today our food is softer, 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. Now. I don't need telepathy to know that you think these are really lame powers. How about one more mutation. Did you know that our brains have been shrinking for the last thirty thousand years.

Some researchers think this means we're getting dumber, because the safety of modern society doesn't require intelligence for survival, but others argue that smaller brains just mean they're more efficient. Maybe our wiring up there takes up less room because it's faster, like when you get a newer, smaller phone that has better RAM than your old one. Hopefully, as my brain reaches peak efficiency, I'll be able to focus the totality of my psyche into some kind of weapon.

Today's episode was written by Christian and produced by Tyler Clang. Brain Stuff is a production of I Heart Radio's How Stuff Works. If you miss Christian and want to hear more about the X Men, check out his podcast about the culture of pop culture, super Context and For more on this and lots of other topics, visit our home planet hows toff works dot com plus for more. Podcast for my heart Radio, visit the heart Radio app, Apple Podcasts, or wherever you listen to your favorite shows. H