The brilliance of bioluminescence - Leslie Kenna

2,326,765 views ・ 2013-05-15

TED-Ed


Please double-click on the English subtitles below to play the video.

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Translator: Andrea McDonough Reviewer: Jessica Ruby
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Imagine a place so dark
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you can't see the nose on your face.
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Eyes opened or closed, it's all the same
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because the sun never shines there.
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Up ahead, you see a light.
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When you creep in to investigate,
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a blue light flits around you.
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"I could watch this forever," you think.
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But you can't
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because the mouth of an anglerfish has just sprung open
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and eaten you alive.
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You are just one of many creatures
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at the bottom of the ocean who learn too late
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to appreciate the power of bioluminescence.
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Bioluminescence refers to the ability
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of certain living things to create light.
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The human body can make stuff
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like ear wax and toe nails,
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but these organisms can turn
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parts of their body into glow sticks.
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It's like nature made them ready to rave.
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Why?
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In one way or another,
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bioluminescence improves a living thing's chances of survival.
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Take the firefly.
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It's ability to glow green
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helps it attract a mate on a warm, summer night,
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but it's just one of many living things that can glow.
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The railroad worm, Phrixothrix hirtus,
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can light up its body in two colors:
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red and green.
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Would you eat something
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that looks like an airport runway?
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Neither would any sensible predator.
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The flashing lights keep the worm safe.
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Then there's the deep sea shrimp,
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Acantherphyra purpurea.
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When it feels threatened,
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it spews a cloud of glowing goo from its mouth.
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Who doesn't run the other way
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when they've just been puked on?
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Plus, that puke attracts bigger predators
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who want to eat the shrimp's enemy.
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So what if you can't bioluminesce?
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No problem!
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There are other ways for living things
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to make bioluminescence work for them,
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even if they weren't born with the equipment to glow.
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Let's revisit the anglerfish
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moments before it tried to eat you.
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That glowing bait on top of its head?
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It comes from a pocket of skin called the esca.
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The esca holds bioluminescent bacteria.
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The anglerfish can't glow there by itself,
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so it holds a sack of glowing bacteria instead.
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Remember the firefly?
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It can actually make itself glow.
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Inside its lantern are two chemicals,
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a luciferin and a luciferase.
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When firefly luciferase and luciferin mix together
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in the presence of oxygen
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and fuel for the cell, called ATP,
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the chemical reaction gives off energy in the form of light.
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Once scientists figured out
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how the firefly creates its luciferase and luciferin,
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they used genetic engineering
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to make this light-producing reaction
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occur inside other living things that can't glow.
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For example, they inserted the genes,
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or instructions, for a cell
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to create firefly luciferase and luciferin into a tobacco plant.
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Once there, the tobacco plant followed the instructions
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slipped into its DNA and lit up like a Christmas tree.
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The beauty of bioluminescence,
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unlike the light from the sun or an incandescent bulb,
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is that it's not hot.
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It takes place in a range of temperatures
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that don't burn a living thing.
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And unlike a glow stick,
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which fades out as the chemicals inside get used up,
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bioluminescent reactions use replenishable resources.
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That's one reason engineers
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are trying to develop bioluminescent trees.
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Just think, if planted on the side of highways,
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they could light the way, using only oxygen
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and other freely available, clean resources to run.
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Talk about survival advantage!
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That could help our planet live longer.
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Do you find yourself thinking of other ways
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to put bioluminescence to good use?
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That glow stick you swing at a rave
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may help you find a mate,
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but how else can bioluminescence improve your survival?
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If you start thinking in this way,
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you have seen the light.
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