Why Your Brain Is In Your Head


[MUSIC] In the animal kingdom, just about wherever
we find brains, they’re wrapped in heads. But being so important, you’d think that evolution
would have … I dunno, looked after the brain a bit better. It just doesn’t make sense that
we wrap our most vital hunk of tissue in this thin candy shell, dangling out in the open
where any low-hanging doorway or fastball can crack it like an egg. BUT, when ya think about it there’s a lot
about the human body that doesn’t immediately make sense. We breathe through the same hole
we eat with, we grow more teeth than we can fit in our mouths, we built our amusement
park next to the garbage dump… To craft this brain story, we’re going to
need some help. And we need to head back to the beginning. With BrainCraft! The very first animals didn’t have brains,
or heads, or really… much of anything going on. But our ancestors DID know left from right. Around 550 million years ago the first animals
with bilateral symmetry branched off from those with radial symmetry
A radial animal like a jellyfish only has two body axes to play with, from head to tentacles
and out from the middle. They’re a bit … two dimensional Bilateral animals suddenly had a new dimension
to play with. Not only could they have a top and a bottom and grow out from the center,
they could have a front and a rear. So many new possibilities!! Every bilateral animal uses the same set of
genes to control how its body is organized head to tail. These genetic choreographers,
called Hox genes, control the developmental dance performed by hundreds of other genes,
instructing an embryo to put the head here or tail there. Hox genes themselves are clustered on the
chromosome, strung together in the same order as the parts of the body they organize. This is the basic body plan that nature has
used to build everything from nematodes to regular toads, from waterbears to polar bears,
and humans to honeybees. The Hox genes of complex animals like humans
and mice aren’t so much different from say, a fly, we just have more of them. Along our
evolutionary journey, these genetic architects were duplicated, allowing the redundant copies
to specialize and sculpt new forms. Early animals turned random jumbles of a few
nerves into telegraph lines from tip to tail, but they still had no central nervous system.
No brains, no elaborate spinal cords, just a simplest of wires connecting front to back.
Turns out that in order to spell “brain”, you need an eye. If you’re in the business of eating, it helps
to have them on the end of your body where the food goes in….the other end is just…
not pleasant. So animals focused their eyespots and other sense organs on their eating ends,
and so more and more nerves began to cluster nearby… this marks the beginnings of a brain. Eyes evolved more than once in different branches
of life. And on those branches, bodies and nervous systems continued to grow more and
more complex. As these early brains became more powerful, and valuable, one branch of
animals started to protect their main nerve cord in a protective wrapper Later, as sensory organs like eyes and scent
receptors became increasingly powerful, so did the brains that processed their information.
Suddenly, they were worth protecting. A group of animals called the craniates began to wrap
theirs in protective skulls, made first of cartilage, and later bone. Hardened skulls meant deadlier jaws, so some
animals developed fins, all the better to escape with. This arms race led to more and
more bony body parts. Our ancestors must have been Daft Punk fans: [SINGING]: “Harder, better, faster, stronger” The first vertebrates that walked out of the
water would diverge into animals as diverse as dinosaurs and dogs, but their basic body
plan was set. Brain inside a skull, up at the eating end, close to the sensory organs. This is why we don’t see more variety in vertebrate
shapes. Evolution is kind of like Taco Bell, a seemingly infinite number of creations made
from essentially the same ingredients. That’s how evolution planted the seed that
put your brain in your head. Now why don’t you put it to good use, and head over to BrainCraft and find out how
it grows. Stay curious. Hey, that’s my line. This video’s part of a three part series all
about “guts”. If you wanna know more about why your body is organized the way that it
is, then check out the rest of these videos. If I’ve uploaded them yet

100 thoughts on “Why Your Brain Is In Your Head

  1. And the VP for United States doesn't believe in evolution. For him the Adam and Eve story makes more sense than this

  2. there was one kind of bracheosaur kind of dino that had a second brain in the tail it was so big that that one wasnt fat enough to control everything

  3. HARDER BETTER FASTER STRONGER

    Work it
    Make it
    Do it
    Make us

    Harder
    Better
    Faster
    Stronger

    More than
    Hour
    Our
    Never

    Ever
    After
    Work is
    Over

    Work it
    Make it
    Do it
    Make us

    Harder
    Better
    Faster
    Stronger

    Work it harder
    Make it better
    Do it faster
    Makes us stronger

    More than ever
    Hour after
    Our work is
    Never over

    Work it harder
    Make it better
    Do it faster
    Makes us stronger

    Work it harder
    Make it better
    Do it faster
    Makes us stronger

    Work it harder
    Make it better
    Do it faster
    Makes us stronger

    Work it harder
    Make it better
    Do it faster
    Makes us stronger

    Work it harder
    Make it better
    Do it faster
    Makes us stronger

    Work it harder
    Make it better
    Do it faster
    Makes us stronger

    Work it harder make it
    Do it faster makes us
    More than ever hour
    Our work is

    Work it harder make it
    Do it faster makes us
    More than ever hour
    Our work is never over

    Work it harder
    Make it better
    Do it faster
    Makes us stronger

    Work it harder make it
    Do it faster makes us
    More than ever hour
    Our work is

    Work it harder make it
    Do it faster makes us
    More than ever hour
    Our work is never over

    Work it harder
    Make it better
    Do it faster
    Makes us stronger

    Work it harder
    Do it faster
    More than ever
    Our work is never over

    Work it harder
    Make it better
    Do it faster
    Makes us stronger

  4. We don't actually grow more teeth than we fit in our mouths. In cultures where they don't eat so much processed food, they have to do more chewing which develops their jaws more than we do in the west. All their teeth fit in their mouths just fine.

  5. Τhough there are many incects like roaches which as far as im concerned have their brain into their body as they can live without a head for some weaks . How come ? Maybe their thicker body is a better place for their brains ?

  6. I knew it had to do with the eyes! My guess was that when looking and navigating your environment it would be easier if the information going from your eye to your brain had a shorter path, so naturally right behind the eyes. I guess that wouldn't really be needed when originally so minuscule tho.

    Im on such a binge with these videos.

  7. The evolution from aquatic life to land is always portrayed with a fish like creature. But weren't plants the first to make the jump by far? How did THAT jump happen 🤔

  8. Great video but too much info in too little time which is difficult to digest! Could you make a summary slide at the end?

  9. It's not like a tree really it's more like a 3d 360 chain link fence Mandelbrot set type deal you know like your brain kinda but with animal lineage instead. Eyes can be eliminated after a brain is achieved if it was ever necessary to obtain one, brain, is another argument.

  10. So with the subject of this video in mind, why is it so hard for some scientists to believe that alien beings could have evolved a similar body type similar to ours, through convergent evolution? Assuming there are any aliens of course, which statistically there almost certainly are. It's a general body type that makes evolutionary sense and has been proven by evolution to work. Yet I have heard many scientist scoff at the idea that any sentient alien life could have a body shape that looks anything like humans or anything that even resembles what we see on earth. Even with the differing conditions of another planet, It seems rather arrogant to so quickly dismiss a body layout that has been proven by evolution to work and be quite effective.

  11. 3:51 I'd disagree slightly. Animals have wildly different parts in the same basic configuration, instead of having the same basic parts in wildly different configurations.

  12. Listen guys, the reason behind the existence of our brains in the head is because it's the safest place for it.

    But the most important question is, where is our mind?
    I believe that the mind has no stable place to remain in. So, sometimes it stay at the Brain, the heart, the stomach, or at the testicles.

    And takes control of where it stays in.

  13. If evolution is real then how come all of the animals did not evolve? Because evolution in not real. If you are going to teach the theory of evolution you must also teach creation, and the story of Adam an Eve.

  14. If our brains were in our stomachs but our eyes, ears nose and mouth were still on our head, would we still feel the same?

  15. Because the cpu should have the fastest connections with the most important sensors like smell, hearing and seeing devices in order to have the quickest response as possible to the outside world, therefore the brain's located closest to them. That results in these devices along with the brain collectively forming a relatively independent module, and humans call it, a head.

  16. That whole "breathing through the same hole we eat with" can be a real inconvenience! Anyone ever choke on your own saliva? (not to the point of respiratory failure but just coughing your ass off). Maybe Genesis is right and God spent like 12 hours on the 6th day of creation making an anatomically counter-productive talking ape.

  17. "There is no higher happiness than wisdom, no better friend than knowledge, and no other saviour than the power of the consciousness."

  18. Hey you could say Stay Smart instead of Stay Curious, because it fits with the name of the channel

Leave a Reply

Your email address will not be published. Required fields are marked *