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  • Thanks to Brilliant for supporting this episode of SciShow.

  • Go to Brilliant.org/SciShow to check out their course on Algorithm Fundamentals.

  • [♩INTRO]

  • Brittle stars may seem a bit boring at first glance.

  • They're basically skinnier, wigglier versions of their relatives, the sea stars.

  • But those are not the only ways they differ from their meatier cousins.

  • Sea stars have eyesone at the end of each arm.

  • But brittle stars are eyeless, so clearly they must not be as cool, right?

  • Except, it turns out they can see.

  • Just with their skin instead of eyes!

  • Vision seems like it would be pretty simple: if you have eyes, you can see.

  • If you don't have eyes, you cannot.

  • But eyes are just a really advanced form of photoreception:

  • the ability to perceive light.

  • And there's lots of animals on our planet that do not have eyes

  • that can still sense light.

  • And it has a name!

  • It's known as extraocular photoreception.

  • Basically, they can sense light with other parts of their bodies,

  • either in addition to or instead of having eyes.

  • The brittle star Ophiocoma wendtii, is one such creature.

  • These brainless, shy animals spend their time hanging out

  • in dark crevices of coral reefs.

  • And they know they're in those crevices because they can

  • react to light and shadow using their skin.

  • Until recently, scientists thought that crystal-like structures

  • in their skin worked together like a big compound eye.

  • Essentially, they believed the crystals could focus light onto nerves

  • running all over the brittle star's body,

  • and that allowed the animals to form images of their environment.

  • And they believed that because they thought there was this big network of nerves

  • running below the crystals.

  • But once they took a closer look with high-tech microscopes,

  • they found that these nerves actually run in between the crystals.

  • Which sinks the whole crystals-focusing-light on them idea.

  • However, they also found that the skin on their arms contains lots of cells

  • filled with light-sensitive proteins called opsins.

  • And it turns out these are in close contact with those nerves.

  • So now, biologists think these cells allow the brittle star to detect light.

  • Basically, when light hits those light-sensitive proteins,

  • the cells send a signal to the nerves, and that causes the brittle star to react.

  • Which, in their case, generally means moving out of the spotlight

  • and back into the dark.

  • It's still not fully known how exactly the nerves produce this response,

  • what with the animals lacking a brain.

  • And they aren't sure whether brittle stars can see shapes

  • or just experience light and shadow.

  • But they're eager to learn more, because there are lots of cases

  • where we would like machines to see without relying on a central control system.

  • It could help cut down the circuitry needs of mobile robots, for example,

  • since they wouldn't need to send all information

  • to their centralizedbrainsto process.

  • And it might make the machines better at tolerating and adapting to damage.

  • Basically, much like brittle stars, localized injuries wouldn't have as big an impact

  • on their overall ability to functionan idea known as graceful degradation.

  • So not only do brittle stars have the superpower of seeing without eyes,

  • they might be able to show us how to design robots with that same ability,

  • so that they can travel into dangerous environments

  • and perform all sorts of helpful tasks.

  • And that makes these eyeless, boneless, brainless animals anything but boring.

  • Thanks for watching this episode of SciShow, which is sponsored by Brilliant.

  • Brilliant offers hands-on courses that can help you

  • cultivate your math and scientific thinking skills.

  • Like, if you want to get a peak at what robotics engineers do every day,

  • you could take their Algorithm Fundamentals course.

  • Algorithms are the codes that underlie everything our machines do.

  • So with this course, you'll gain a deeper understanding of how we get robots,

  • or any computer, to do what we want.

  • With a premium subscription, you'll get access to it

  • and all of Brilliant's other courses, as well as their other educational content.

  • And if you're one of the first 200 people to sign up at Brilliant.org/SciShow,

  • you'll get 20% off an annual premium subscription.

  • So if you want to deepen your STEM skills,

  • be sure to head on over to that link and check out what Brilliant has to offer!

  • [♩OUTRO]

Thanks to Brilliant for supporting this episode of SciShow.

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脆い星がロボットに皮膚で見ることを教えてくれるかもしれない (Brittle Stars Could Teach Robots To See With Their Skin)

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    林宜悉 に公開 2021 年 01 月 14 日
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