1 00:00:01,940 --> 00:00:09,009 Our planet's diverse, thriving ecosystems 2 00:00:09,009 --> 00:00:12,009 may seem like permanent fixtures, 3 00:00:12,009 --> 00:00:15,009 but they're actually vulnerable to collapse. 4 00:00:15,009 --> 00:00:17,010 Jungles can become deserts, 5 00:00:17,010 --> 00:00:19,010 and reefs can become lifeless rocks, 6 00:00:19,010 --> 00:00:23,010 even without cataclysmic events like volcanoes and asteroids. 7 00:00:23,010 --> 00:00:26,010 What makes one ecosystem strong 8 00:00:26,010 --> 00:00:28,010 and another weak in the face of change? 9 00:00:28,010 --> 00:00:32,009 The answer, to a large extent, is biodiversity. 10 00:00:32,009 --> 00:00:35,329 Biodiversity is built out of three intertwined features, 11 00:00:35,990 --> 00:00:40,450 ecosystem diversity, species diversity, and genetic diversity. 12 00:00:41,030 --> 00:00:44,210 The more intertwining there is between these features, 13 00:00:44,609 --> 00:00:47,250 the denser and more resilient the weave becomes. 14 00:00:48,130 --> 00:00:49,329 Take the Amazon rainforest, 15 00:00:50,109 --> 00:00:52,850 one of the most biodiverse regions on Earth 16 00:00:52,850 --> 00:00:56,250 due to its complex ecosystems, huge mix of species, 17 00:00:56,250 --> 00:00:59,049 and the genetic variety within those species. 18 00:00:59,689 --> 00:01:01,350 Here are tangled liana vines, 19 00:01:01,350 --> 00:01:04,409 which crawl up from the forest floor to the canopy, 20 00:01:05,189 --> 00:01:08,549 intertwining with treetops and growing thick wooded stems 21 00:01:08,549 --> 00:01:10,469 that support these towering trees. 22 00:01:11,569 --> 00:01:15,969 Helped along by the vines, trees provide the seeds, fruits, and leaves 23 00:01:15,969 --> 00:01:18,969 to herbivores such as the tapir and the agouti, 24 00:01:19,530 --> 00:01:22,569 which disperse their seeds throughout the forest so they can grow. 25 00:01:23,650 --> 00:01:26,030 Leftovers are consumed by the millions of insects 26 00:01:26,030 --> 00:01:29,250 that decompose and recycle nutrients to create rich soil. 27 00:01:30,090 --> 00:01:34,290 The rainforest is a huge system filled with many smaller systems like this, 28 00:01:34,810 --> 00:01:37,049 each packed with interconnected species. 29 00:01:38,030 --> 00:01:42,150 Every link provides stability to the next, strengthening biodiversity's weave. 30 00:01:43,090 --> 00:01:48,049 That weave is further reinforced by the genetic diversity within individual species, 31 00:01:48,590 --> 00:01:50,530 which allows them to cope with changes. 32 00:01:51,129 --> 00:01:55,629 Species that lack genetic diversity due to isolation or low population numbers 33 00:01:55,629 --> 00:01:59,629 are much more vulnerable to fluctuations caused by climate change, 34 00:01:59,629 --> 00:02:02,629 disease, or habitat fragmentation. 35 00:02:02,629 --> 00:02:06,629 Whenever a species disappears because of its weakened gene pool, 36 00:02:06,629 --> 00:02:10,629 a knot is untied, and parts of the net disintegrate. 37 00:02:10,629 --> 00:02:14,629 So, what if we were to remove one species from the rainforest? 38 00:02:14,629 --> 00:02:16,629 Would the system fall apart? 39 00:02:16,629 --> 00:02:17,629 Probably not. 40 00:02:17,629 --> 00:02:20,629 The volume of species, their genetic diversity, 41 00:02:20,629 --> 00:02:22,629 and the complexity of the ecosystems 42 00:02:22,629 --> 00:02:25,629 form such rich biodiversity in this forest 43 00:02:25,629 --> 00:02:29,629 that one species gap in the weave won't cause it to unravel. 44 00:02:29,629 --> 00:02:33,629 The forest can stay resilient and recover from change. 45 00:02:33,629 --> 00:02:35,629 But that's not true in every case. 46 00:02:35,629 --> 00:02:39,629 In some environments, taking away just one important component 47 00:02:39,629 --> 00:02:42,629 can undermine the entire system. 48 00:02:42,629 --> 00:02:44,629 Take coral reefs, for instance. 49 00:02:44,629 --> 00:02:47,629 Many organisms in a reef are dependent on the coral. 50 00:02:47,629 --> 00:02:51,629 It provides key microhabitats, shelter, and breeding grounds 51 00:02:51,629 --> 00:02:55,650 for thousands of species of fish, crustaceans, and mollusks. 52 00:02:56,289 --> 00:03:00,349 Corals also form interdependent relationships with fungi and bacteria. 53 00:03:01,189 --> 00:03:02,889 The coral itself is a loom 54 00:03:02,889 --> 00:03:06,229 that allows the tangled net of biodiversity to be woven. 55 00:03:07,050 --> 00:03:09,129 That makes coral a keystone organism, 56 00:03:09,669 --> 00:03:12,069 one that many others depend on for their survival. 57 00:03:12,990 --> 00:03:15,389 So what happens when destructive fishing practices, 58 00:03:15,990 --> 00:03:17,949 pollution, and ocean acidification 59 00:03:17,949 --> 00:03:20,550 weaken coral or even kill it altogether? 60 00:03:21,629 --> 00:03:23,509 Exactly what you might think. 61 00:03:23,509 --> 00:03:28,289 The loss of this keystone species leaves its dependents at a loss too, 62 00:03:28,289 --> 00:03:31,069 threatening the entire fabric of the reef. 63 00:03:31,069 --> 00:03:34,270 Ecosystem, species, and genetic diversity 64 00:03:34,270 --> 00:03:37,949 together form the complex tangled weave of biodiversity 65 00:03:37,949 --> 00:03:41,389 that is vital for the survival of organisms on Earth. 66 00:03:41,389 --> 00:03:44,909 We humans are woven into this biodiversity too. 67 00:03:44,909 --> 00:03:49,189 When just a few strands are lost, our own well-being is threatened, 68 00:03:49,189 --> 00:03:53,229 cut too many links, and we risk unraveling it all. 69 00:03:53,229 --> 00:03:55,530 What the future brings is unpredictable, 70 00:03:55,530 --> 00:03:58,569 but biodiversity can give us an insurance policy, 71 00:03:58,569 --> 00:04:02,389 Earth's own safety net, to safeguard our survival.