0:00:14.226,0:00:15.931 Imagine a place so dark 0:00:15.931,0:00:18.149 you can't see the nose on your face. 0:00:18.149,0:00:21.217 Eyes opened or closed, it's all the same 0:00:21.217,0:00:23.985 because the sun never shines there. 0:00:23.985,0:00:26.073 Up ahead, you see a light. 0:00:26.073,0:00:27.961 When you creep in to investigate, 0:00:27.961,0:00:30.212 a blue light flits around you. 0:00:30.212,0:00:32.396 "I could watch this forever," you think. 0:00:32.396,0:00:33.417 But you can't 0:00:33.417,0:00:36.268 because the mouth of an anglerfish has just sprung open 0:00:36.268,0:00:38.471 and eaten you alive. 0:00:38.471,0:00:40.046 You are just one of many creatures 0:00:40.046,0:00:42.352 at the bottom of the ocean who learn too late 0:00:42.352,0:00:45.939 to appreciate the power of bioluminescence. 0:00:45.939,0:00:48.233 Bioluminescence refers to the ability 0:00:48.233,0:00:50.858 of certain living things to create light. 0:00:50.858,0:00:52.535 The human body can make stuff 0:00:52.535,0:00:55.626 like ear wax and toe nails, 0:00:55.626,0:00:57.214 but these organisms can turn 0:00:57.214,0:00:59.862 parts of their body into glow sticks. 0:00:59.862,0:01:02.230 It's like nature made them ready to rave. 0:01:02.230,0:01:03.203 Why? 0:01:03.203,0:01:04.539 In one way or another, 0:01:04.539,0:01:08.601 bioluminescence improves a living thing's chances of survival. 0:01:08.601,0:01:10.044 Take the firefly. 0:01:10.044,0:01:11.603 It's ability to glow green 0:01:11.603,0:01:14.434 helps it attract a mate on a warm, summer night, 0:01:14.434,0:01:17.342 but it's just one of many living things that can glow. 0:01:17.342,0:01:20.054 The railroad worm, Phrixothrix hirtus, 0:01:20.054,0:01:21.936 can light up its body in two colors: 0:01:21.936,0:01:23.171 red and green. 0:01:23.171,0:01:24.261 Would you eat something 0:01:24.261,0:01:26.561 that looks like an airport runway? 0:01:26.561,0:01:28.813 Neither would any sensible predator. 0:01:28.813,0:01:31.719 The flashing lights keep the worm safe. 0:01:31.719,0:01:33.778 Then there's the deep sea shrimp, 0:01:33.778,0:01:35.527 Acantherphyra purpurea. 0:01:35.527,0:01:36.862 When it feels threatened, 0:01:36.862,0:01:40.027 it spews a cloud of glowing goo from its mouth. 0:01:40.027,0:01:41.326 Who doesn't run the other way 0:01:41.326,0:01:43.600 when they've just been puked on? 0:01:43.600,0:01:46.143 Plus, that puke attracts bigger predators 0:01:46.143,0:01:48.386 who want to eat the shrimp's enemy. 0:01:48.386,0:01:50.687 So what if you can't bioluminesce? 0:01:50.687,0:01:51.741 No problem! 0:01:51.741,0:01:53.322 There are other ways for living things 0:01:53.322,0:01:55.524 to make bioluminescence work for them, 0:01:55.524,0:01:58.556 even if they weren't born with the equipment to glow. 0:01:58.556,0:02:00.400 Let's revisit the anglerfish 0:02:00.400,0:02:02.402 moments before it tried to eat you. 0:02:02.402,0:02:04.196 That glowing bait on top of its head? 0:02:04.196,0:02:07.181 It comes from a pocket of skin called the esca. 0:02:07.181,0:02:10.035 The esca holds bioluminescent bacteria. 0:02:10.035,0:02:12.290 The anglerfish can't glow there by itself, 0:02:12.290,0:02:16.327 so it holds a sack of glowing bacteria instead. 0:02:16.327,0:02:18.001 Remember the firefly? 0:02:18.001,0:02:20.083 It can actually make itself glow. 0:02:20.083,0:02:22.674 Inside its lantern are two chemicals, 0:02:22.674,0:02:25.190 a luciferin and a luciferase. 0:02:25.190,0:02:28.095 When firefly luciferase and luciferin mix together 0:02:28.095,0:02:29.389 in the presence of oxygen 0:02:29.389,0:02:31.474 and fuel for the cell, called ATP, 0:02:31.474,0:02:35.184 the chemical reaction gives off energy in the form of light. 0:02:35.184,0:02:36.644 Once scientists figured out 0:02:36.644,0:02:39.606 how the firefly creates its luciferase and luciferin, 0:02:39.606,0:02:41.193 they used genetic engineering 0:02:41.193,0:02:43.110 to make this light-producing reaction 0:02:43.110,0:02:46.259 occur inside other living things that can't glow. 0:02:46.259,0:02:48.461 For example, they inserted the genes, 0:02:48.461,0:02:50.123 or instructions, for a cell 0:02:50.123,0:02:54.363 to create firefly luciferase and luciferin into a tobacco plant. 0:02:54.363,0:02:57.216 Once there, the tobacco plant followed the instructions 0:02:57.216,0:03:01.231 slipped into its DNA and lit up like a Christmas tree. 0:03:01.231,0:03:02.794 The beauty of bioluminescence, 0:03:02.794,0:03:05.544 unlike the light from the sun or an incandescent bulb, 0:03:05.544,0:03:07.136 is that it's not hot. 0:03:07.136,0:03:09.422 It takes place in a range of temperatures 0:03:09.422,0:03:11.406 that don't burn a living thing. 0:03:11.406,0:03:12.844 And unlike a glow stick, 0:03:12.844,0:03:15.720 which fades out as the chemicals inside get used up, 0:03:15.720,0:03:19.466 bioluminescent reactions use replenishable resources. 0:03:19.466,0:03:20.931 That's one reason engineers 0:03:20.931,0:03:24.221 are trying to develop bioluminescent trees. 0:03:24.221,0:03:26.767 Just think, if planted on the side of highways, 0:03:26.767,0:03:28.817 they could light the way, using only oxygen 0:03:28.817,0:03:32.464 and other freely available, clean resources to run. 0:03:32.464,0:03:34.539 Talk about survival advantage! 0:03:34.539,0:03:37.157 That could help our planet live longer. 0:03:37.157,0:03:39.494 Do you find yourself thinking of other ways 0:03:39.494,0:03:42.363 to put bioluminescence to good use? 0:03:42.363,0:03:44.402 That glow stick you swing at a rave 0:03:44.402,0:03:46.001 may help you find a mate, 0:03:46.001,0:03:49.754 but how else can bioluminescence improve your survival? 0:03:49.754,0:03:51.631 If you start thinking in this way, 0:03:51.631,0:03:53.466 you have seen the light.