1 00:00:06,630 --> 00:00:11,734 Our planet's diverse thriving ecosystems may seem like permanent fixtures, 2 00:00:11,734 --> 00:00:15,037 but they're actually vulnerable to collapse. 3 00:00:15,037 --> 00:00:17,034 Jungles can become deserts, 4 00:00:17,034 --> 00:00:19,666 and reefs can become lifeless rocks, 5 00:00:19,666 --> 00:00:23,972 even without cataclysmic events, like volcanoes and asteroids. 6 00:00:23,972 --> 00:00:28,466 What makes one ecosystem strong and another weak in the face of change? 7 00:00:28,466 --> 00:00:32,217 The answer, to a large extent, is biodiversity. 8 00:00:32,217 --> 00:00:35,692 Biodiversity is built out of three intertwined features: 9 00:00:35,692 --> 00:00:37,720 ecosystem diversity, 10 00:00:37,720 --> 00:00:39,585 species diversity, 11 00:00:39,585 --> 00:00:41,696 and genetic diversity. 12 00:00:41,696 --> 00:00:44,589 The more intertwining there is between these features, 13 00:00:44,589 --> 00:00:48,321 the denser and more resilient the weave becomes. 14 00:00:48,321 --> 00:00:50,305 Take the Amazon rainforest, 15 00:00:50,305 --> 00:00:53,292 one of the most biodiverse regions on Earth 16 00:00:53,292 --> 00:00:55,289 due to its complex ecosystems, 17 00:00:55,289 --> 00:00:57,086 huge mix of species, 18 00:00:57,086 --> 00:00:59,849 and the genetic variety within those species. 19 00:00:59,849 --> 00:01:01,678 Here are tangled liana vines, 20 00:01:01,678 --> 00:01:04,918 which crawl up from the forest floor to the canopy, 21 00:01:04,918 --> 00:01:07,047 intertwining with treetops 22 00:01:07,047 --> 00:01:11,657 and growing thick wooden stems that support these towering trees. 23 00:01:11,657 --> 00:01:13,299 Helped along by the vines, 24 00:01:13,299 --> 00:01:16,963 trees provide the seeds, fruits and leaves to herbivores, 25 00:01:16,963 --> 00:01:19,821 such as the tapir and the agouti, 26 00:01:19,821 --> 00:01:23,778 which disperse their seeds throughout the forest so they can grow. 27 00:01:23,778 --> 00:01:26,207 Leftovers are consumed by the millions of insects 28 00:01:26,207 --> 00:01:30,223 that decompose and recycle nutrients to create rich soil. 29 00:01:30,223 --> 00:01:34,910 The rainforest is a huge system filled with many smaller systems, like this, 30 00:01:34,910 --> 00:01:38,188 each packed with interconnected species. 31 00:01:38,188 --> 00:01:40,471 Every link provides stability to the next, 32 00:01:40,471 --> 00:01:43,329 strengthening biodiversity's weave. 33 00:01:43,329 --> 00:01:45,092 That weave is further reinforced 34 00:01:45,092 --> 00:01:48,976 by the genetic diversity within individual species, 35 00:01:48,976 --> 00:01:51,484 which allows them to cope with changes. 36 00:01:51,484 --> 00:01:54,441 Species that lack genetic diversity due to isolation 37 00:01:54,441 --> 00:01:56,182 or low population numbers, 38 00:01:56,182 --> 00:01:58,491 are much more vulnerable to fluctuations 39 00:01:58,491 --> 00:02:03,042 caused by climate change, disease or habitat fragmentation. 40 00:02:03,042 --> 00:02:06,713 Whenever a species disappears because of its weakened gene pool, 41 00:02:06,713 --> 00:02:10,945 a knot is untied and parts of the net disintegrate. 42 00:02:10,945 --> 00:02:14,511 So, what if we were to remove one species from the rainforest? 43 00:02:14,511 --> 00:02:16,945 Would the system fall apart? 44 00:02:16,945 --> 00:02:18,388 Probably not. 45 00:02:18,388 --> 00:02:19,610 The volume of species, 46 00:02:19,610 --> 00:02:21,062 their genetic diversity, 47 00:02:21,062 --> 00:02:23,249 and the complexity of the ecosystems 48 00:02:23,249 --> 00:02:26,135 form such rich biodiversity in this forest 49 00:02:26,135 --> 00:02:30,802 that one species gap in the weave won't cause it to unravel. 50 00:02:30,802 --> 00:02:34,457 The forest can stay resilient and recover from change. 51 00:02:34,457 --> 00:02:36,509 But that's not true in every case. 52 00:02:36,509 --> 00:02:40,271 In some environments, taking away just one important component 53 00:02:40,271 --> 00:02:42,747 can undermine the entire system. 54 00:02:42,747 --> 00:02:44,963 Take coral reefs, for instance. 55 00:02:44,963 --> 00:02:48,215 Many organisms in a reef are dependent on the coral. 56 00:02:48,215 --> 00:02:51,801 It provides key microhabitats, shelter and breeding grounds 57 00:02:51,801 --> 00:02:56,397 for thousand of species of fish, crustaceans and mollusks. 58 00:02:56,397 --> 00:03:01,186 Corals also form interdependent relationships with fungi and bacteria. 59 00:03:01,186 --> 00:03:02,987 The coral itself is a loom 60 00:03:02,987 --> 00:03:07,261 that allows the tangled net of biodiversity to be woven. 61 00:03:07,261 --> 00:03:09,624 That makes coral a keystone organism, 62 00:03:09,624 --> 00:03:12,974 one that many others depend on for their suvival. 63 00:03:12,974 --> 00:03:15,670 So what happens when destructive fishing practices, 64 00:03:15,670 --> 00:03:18,237 pollution and ocean acidification 65 00:03:18,237 --> 00:03:21,775 weaken coral or even kill it altogether? 66 00:03:21,775 --> 00:03:23,695 Exactly what you might think. 67 00:03:23,695 --> 00:03:28,478 The loss of this keystone species leaves its dependents at a loss, too, 68 00:03:28,478 --> 00:03:31,241 threatening the entire fabric of the reef. 69 00:03:31,241 --> 00:03:34,232 Ecosystem, species and genetic diversity 70 00:03:34,232 --> 00:03:37,991 together form the complex tangled weave of biodiversity 71 00:03:37,991 --> 00:03:41,593 that is vital for the survival of organisms on Earth. 72 00:03:41,593 --> 00:03:44,711 We humans are woven into this biodiversity, too. 73 00:03:44,711 --> 00:03:46,983 When just a few strands are lost, 74 00:03:46,983 --> 00:03:49,394 our own well-being is threatened. 75 00:03:49,394 --> 00:03:52,796 Cut too many links, and we risk unraveling it all. 76 00:03:52,796 --> 00:03:55,365 What the future brings is unpredictable, 77 00:03:55,365 --> 00:03:58,301 but biodiversity can give us an insurance policy, 78 00:03:58,301 --> 00:04:02,597 Earth's own safety net to safeguard our survival.