WEBVTT 00:00:14.226 --> 00:00:15.931 Imagine a place so dark 00:00:15.931 --> 00:00:18.149 you can't see the nose on your face. 00:00:18.149 --> 00:00:21.217 Eyes opened or closed, it's all the same 00:00:21.217 --> 00:00:23.985 because the sun never shines there. 00:00:23.985 --> 00:00:26.073 Up ahead, you see a light. 00:00:26.073 --> 00:00:27.961 When you creep in to investigate, 00:00:27.961 --> 00:00:30.212 a blue light flits around you. 00:00:30.212 --> 00:00:32.396 "I could watch this forever," you think. 00:00:32.396 --> 00:00:33.417 But you can't 00:00:33.417 --> 00:00:36.268 because the mouth of an anglerfish has just sprung open 00:00:36.268 --> 00:00:38.471 and eaten you alive. 00:00:38.471 --> 00:00:40.046 You are just one of many creatures 00:00:40.046 --> 00:00:42.352 at the bottom of the ocean who learn too late 00:00:42.352 --> 00:00:45.939 to appreciate the power of bioluminescence. 00:00:45.939 --> 00:00:48.233 Bioluminescence refers to the ability 00:00:48.233 --> 00:00:50.858 of certain living things to create light. 00:00:50.858 --> 00:00:52.535 The human body can make stuff 00:00:52.535 --> 00:00:55.626 like ear wax and toe nails, 00:00:55.626 --> 00:00:57.214 but these organisms can turn 00:00:57.214 --> 00:00:59.862 parts of their body into glow sticks. 00:00:59.862 --> 00:01:02.230 It's like nature made them ready to rave. 00:01:02.230 --> 00:01:03.203 Why? 00:01:03.203 --> 00:01:04.539 In one way or another, 00:01:04.539 --> 00:01:08.601 bioluminescence improves a living thing's chances of survival. 00:01:08.601 --> 00:01:10.044 Take the firefly. 00:01:10.044 --> 00:01:11.603 It's ability to glow green 00:01:11.603 --> 00:01:14.434 helps it attract a mate on a warm, summer night, 00:01:14.434 --> 00:01:17.342 but it's just one of many living things that can glow. 00:01:17.342 --> 00:01:20.054 The railroad worm, Phrixothrix hirtus, 00:01:20.054 --> 00:01:21.936 can light up its body in two colors: 00:01:21.936 --> 00:01:23.171 red and green. 00:01:23.171 --> 00:01:24.261 Would you eat something 00:01:24.261 --> 00:01:26.561 that looks like an airport runway? 00:01:26.561 --> 00:01:28.813 Neither would any sensible predator. 00:01:28.813 --> 00:01:31.719 The flashing lights keep the worm safe. 00:01:31.719 --> 00:01:33.778 Then there's the deep sea shrimp, 00:01:33.778 --> 00:01:35.527 Acantherphyra purpurea. 00:01:35.527 --> 00:01:36.862 When it feels threatened, 00:01:36.862 --> 00:01:40.027 it spews a cloud of glowing goo from its mouth. 00:01:40.027 --> 00:01:41.326 Who doesn't run the other way 00:01:41.326 --> 00:01:43.600 when they've just been puked on? 00:01:43.600 --> 00:01:46.143 Plus, that puke attracts bigger predators 00:01:46.143 --> 00:01:48.386 who want to eat the shrimp's enemy. 00:01:48.386 --> 00:01:50.687 So what if you can't bioluminesce? 00:01:50.687 --> 00:01:51.741 No problem! 00:01:51.741 --> 00:01:53.322 There are other ways for living things 00:01:53.322 --> 00:01:55.524 to make bioluminescence work for them, 00:01:55.524 --> 00:01:58.556 even if they weren't born with the equipment to glow. 00:01:58.556 --> 00:02:00.400 Let's revisit the anglerfish 00:02:00.400 --> 00:02:02.402 moments before it tried to eat you. 00:02:02.402 --> 00:02:04.196 That glowing bait on top of its head? 00:02:04.196 --> 00:02:07.181 It comes from a pocket of skin called the esca. 00:02:07.181 --> 00:02:10.035 The esca holds bioluminescent bacteria. 00:02:10.035 --> 00:02:12.290 The anglerfish can't glow there by itself, 00:02:12.290 --> 00:02:16.327 so it holds a sack of glowing bacteria instead. 00:02:16.327 --> 00:02:18.001 Remember the firefly? 00:02:18.001 --> 00:02:20.083 It can actually make itself glow. 00:02:20.083 --> 00:02:22.674 Inside its lantern are two chemicals, 00:02:22.674 --> 00:02:25.190 a luciferin and a luciferase. 00:02:25.190 --> 00:02:28.095 When firefly luciferase and luciferin mix together 00:02:28.095 --> 00:02:29.389 in the presence of oxygen 00:02:29.389 --> 00:02:31.474 and fuel for the cell, called ATP, 00:02:31.474 --> 00:02:35.184 the chemical reaction gives off energy in the form of light. 00:02:35.184 --> 00:02:36.644 Once scientists figured out 00:02:36.644 --> 00:02:39.606 how the firefly creates its luciferase and luciferin, 00:02:39.606 --> 00:02:41.193 they used genetic engineering 00:02:41.193 --> 00:02:43.110 to make this light-producing reaction 00:02:43.110 --> 00:02:46.259 occur inside other living things that can't glow. 00:02:46.259 --> 00:02:48.461 For example, they inserted the genes, 00:02:48.461 --> 00:02:50.123 or instructions, for a cell 00:02:50.123 --> 00:02:54.363 to create firefly luciferase and luciferin into a tobacco plant. 00:02:54.363 --> 00:02:57.216 Once there, the tobacco plant followed the instructions 00:02:57.216 --> 00:03:01.231 slipped into its DNA and lit up like a Christmas tree. 00:03:01.231 --> 00:03:02.794 The beauty of bioluminescence, 00:03:02.794 --> 00:03:05.544 unlike the light from the sun or an incandescent bulb, 00:03:05.544 --> 00:03:07.136 is that it's not hot. 00:03:07.136 --> 00:03:09.422 It takes place in a range of temperatures 00:03:09.422 --> 00:03:11.406 that don't burn a living thing. 00:03:11.406 --> 00:03:12.844 And unlike a glow stick, 00:03:12.844 --> 00:03:15.720 which fades out as the chemicals inside get used up, 00:03:15.720 --> 00:03:19.466 bioluminescent reactions use replenishable resources. 00:03:19.466 --> 00:03:20.931 That's one reason engineers 00:03:20.931 --> 00:03:24.221 are trying to develop bioluminescent trees. 00:03:24.221 --> 00:03:26.767 Just think, if planted on the side of highways, 00:03:26.767 --> 00:03:28.817 they could light the way, using only oxygen 00:03:28.817 --> 00:03:32.464 and other freely available, clean resources to run. 00:03:32.464 --> 00:03:34.539 Talk about survival advantage! 00:03:34.539 --> 00:03:37.157 That could help our planet live longer. 00:03:37.157 --> 00:03:39.494 Do you find yourself thinking of other ways 00:03:39.494 --> 00:03:42.363 to put bioluminescence to good use? 00:03:42.363 --> 00:03:44.402 That glow stick you swing at a rave 00:03:44.402 --> 00:03:46.001 may help you find a mate, 00:03:46.001 --> 00:03:49.754 but how else can bioluminescence improve your survival? 00:03:49.754 --> 00:03:51.631 If you start thinking in this way, 00:03:51.631 --> 00:03:53.466 you have seen the light.