WEBVTT 00:00:16.046 --> 00:00:19.000 "Stories from the Sea" 00:00:19.000 --> 00:00:23.953 "Urchin Odyssey: Sex Among Plankton" 00:00:25.000 --> 00:00:28.000 I must look rather strange to you, 00:00:28.000 --> 00:00:31.015 all covered in spines, 00:00:31.015 --> 00:00:33.845 without even a face. 00:00:35.261 --> 00:00:38.983 But I've taken many forms during my life. 00:00:39.429 --> 00:00:42.292 I started out just like you, 00:00:42.292 --> 00:00:45.000 a tiny egg in a watery world. 00:00:45.846 --> 00:00:48.000 My parents never knew each other. 00:00:48.000 --> 00:00:50.000 One moonlit night before a storm, 00:00:50.000 --> 00:00:53.000 thousands of urchins, clams and corals 00:00:53.000 --> 00:00:57.000 released trillions of sperm and eggs into the open sea. 00:01:08.815 --> 00:01:11.738 My father's sperm somehow met my mother's egg, 00:01:11.738 --> 00:01:13.676 and they fused. 00:01:15.492 --> 00:01:17.000 Fertilization. 00:01:17.584 --> 00:01:21.107 Instantly, I became an embryo the size of a speck of dust. 00:01:21.107 --> 00:01:24.076 After a few hours of drifting, 00:01:24.076 --> 00:01:27.000 I cleaved in two, then four, 00:01:27.000 --> 00:01:30.261 then eight cells. Then so many I lost count. 00:01:31.414 --> 00:01:33.000 In less than a day, 00:01:33.000 --> 00:01:36.384 I developed a gut and a skeleton. 00:01:36.384 --> 00:01:39.000 I became a rocket ship, 00:01:39.000 --> 00:01:40.646 a pluteus larva. 00:01:42.737 --> 00:01:44.492 I floated through the world of plankton, 00:01:44.492 --> 00:01:47.415 searching for tiny algae to eat. 00:01:49.676 --> 00:01:50.707 For weeks, 00:01:50.707 --> 00:01:53.430 I was surrounded by all kinds of organisms, 00:01:53.430 --> 00:01:55.800 larvae of all sorts. 00:01:57.646 --> 00:02:00.000 Most are so different from their adult form 00:02:00.000 --> 00:02:03.215 that biologists have a tough time figuring out who they are. 00:02:11.492 --> 00:02:14.000 Try matching these youngsters to their parents. 00:02:16.292 --> 00:02:18.400 This veliger larva 00:02:18.400 --> 00:02:20.000 will turn into a snail. 00:02:20.000 --> 00:02:23.430 This zoea, into a crab. 00:02:23.430 --> 00:02:27.000 And this planula into a cnidaria jelly. 00:02:29.507 --> 00:02:33.200 Some of my young companions are easier to picture as grown-ups. 00:02:34.753 --> 00:02:37.138 These baby jellies, known as ephyrae 00:02:37.138 --> 00:02:41.323 already resemble their beautiful but deadly parents. 00:02:42.584 --> 00:02:44.200 Here in the plankton, 00:02:44.200 --> 00:02:47.615 there's more than one way to get your genes into the next generation. 00:02:50.676 --> 00:02:52.000 Most medusa jellies 00:02:52.000 --> 00:02:54.584 make special structures called polyps 00:02:54.584 --> 00:02:58.153 that simply bud off babies with no need for sex. 00:02:59.922 --> 00:03:01.307 Salps are similar. 00:03:01.815 --> 00:03:06.107 When food is abundant, they just clone themselves into long chains. 00:03:09.153 --> 00:03:13.030 A plankton is full of surprises when it comes to sex. 00:03:14.830 --> 00:03:16.723 Meet the hermaphrodites. 00:03:17.830 --> 00:03:20.000 These comb jellies and arrow worms 00:03:20.000 --> 00:03:23.000 produce, store and release both sperm and eggs. 00:03:24.445 --> 00:03:26.000 They can fertilize themselves 00:03:26.000 --> 00:03:28.000 or another. 00:03:32.383 --> 00:03:34.000 When you're floating in a vast sea, 00:03:34.000 --> 00:03:36.892 with little control over who you may meet, 00:03:36.892 --> 00:03:39.476 it can pay to play both sides of the field. 00:03:41.905 --> 00:03:43.830 The majority of species here, however, 00:03:43.845 --> 00:03:47.876 never mate, nor form any sort of lasting bonds. 00:03:49.306 --> 00:03:51.153 That was my parents' strategy. 00:03:53.491 --> 00:03:56.030 There were so many of us pluteus larvae, 00:03:56.030 --> 00:04:00.107 I just hid in the crowd while most of my kin were devoured. 00:04:03.475 --> 00:04:07.307 Not all parents leave the survival of their offspring to chance. 00:04:08.199 --> 00:04:10.000 Some have far fewer young, 00:04:10.000 --> 00:04:12.276 and take much better care of them, 00:04:12.276 --> 00:04:15.076 brooding their precious cargo for days, even months. 00:04:17.306 --> 00:04:19.000 This speedy copepod 00:04:19.000 --> 00:04:21.861 totes her beautifully packaged eggs for days. 00:04:23.307 --> 00:04:27.015 This phronima crustacean carries her babies on her chest, 00:04:27.307 --> 00:04:30.000 then carefully places them in a gelatinous barrel. 00:04:38.000 --> 00:04:41.000 But the black-eyed squid takes the prize. 00:04:41.000 --> 00:04:45.353 She cradles her eggs in long arms for nine months, 00:04:45.353 --> 00:04:49.230 the same time it takes to gestate a human infant. 00:04:52.661 --> 00:04:57.000 Eventually all youngsters have to make it on their own in this drifting world. 00:05:00.092 --> 00:05:03.338 Some will spend their whole lives in the plankton, 00:05:03.338 --> 00:05:06.815 but others, like me, move on. 00:05:10.369 --> 00:05:12.661 A few weeks after I was conceived, 00:05:12.661 --> 00:05:14.169 I decided to settle down 00:05:15.784 --> 00:05:19.107 and metamorphosed into a recognizable urchin. 00:05:22.737 --> 00:05:25.092 So now you know a bit of my story. 00:05:25.092 --> 00:05:28.984 I may just be a slow-moving ball of spines, 00:05:28.984 --> 00:05:32.629 but don't let my calm adult exterior fool you. 00:05:34.799 --> 00:05:36.953 I was a rocket ship. 00:05:37.613 --> 00:05:39.923 I was a wild child.