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Our planet's diverse thriving ecosystems[br]may seem like permanent fixtures,

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but they're actually [br]vulnerable to collapse.

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Jungles can become deserts,

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and reefs can become lifeless rocks,

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even without cataclysmic events, [br]like volcanoes and asteroids.

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What makes one ecosystem strong[br]and another weak in the face of change?

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The answer, to a large extent,[br]is biodiversity.

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Biodiversity is built out [br]of three intertwined features:

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ecosystem diversity,

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species diversity,

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and genetic diversity.

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The more intertwining [br]there is between these features,

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the denser and more resilient [br]the weave becomes.

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Take the Amazon rainforest,

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one of the most biodiverse [br]regions on Earth

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due to its complex ecosystems,

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huge mix of species,

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and the genetic variety [br]within those species.

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Here are tangled liana vines,

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which crawl up from the forest floor [br]to the canopy,

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intertwining with treetops

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and growing thick wooden stems[br]that support these towering trees.

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Helped along by the vines,

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trees provide the seeds, fruits[br]and leaves to herbivores,

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such as the tapir and the agouti,

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which disperse their seeds[br]throughout the forest so they can grow.

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Leftovers are consumed [br]by the millions of insects

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that decompose and recycle nutrients[br]to create rich soil.

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The rainforest is a huge system filled[br]with many smaller systems, like this,

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each packed with interconnected species.

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Every link provides stability to the next,

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strengthening biodiversity's weave.

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That weave is further reinforced

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by the genetic diversity [br]within individual species,

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which allows them to cope with changes.

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Species that lack genetic diversity[br]due to isolation

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or low population numbers,

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are much more vulnerable [br]to fluctuations

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caused by climate change, disease[br]or habitat fragmentation.

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Whenever a species disappears[br]because of its weakened gene pool,

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a knot is untied [br]and parts of the net disintegrate.

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So, what if we were to remove one species[br]from the rainforest?

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Would the system fall apart?

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Probably not.

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The volume of species,

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their genetic diversity,

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and the complexity of the ecosystems

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form such rich biodiversity in this forest

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that one species gap in the weave[br]won't cause it to unravel.

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The forest can stay resilient[br]and recover from change.

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But that's not true in every case.

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In some environments, taking away[br]just one important component

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can undermine the entire system.

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Take coral reefs, for instance.

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Many organisms in a reef[br]are dependent on the coral.

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It provides key microhabitats,[br]shelter and breeding grounds

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for thousand of species of fish,[br]crustaceans and mollusks.

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Corals also form interdependent [br]relationships with fungi and bacteria.

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The coral itself is a loom

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that allows the tangled net [br]of biodiversity to be woven.

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That makes coral a keystone organism,

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one that many others depend on[br]for their suvival.

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So what happens when destructive[br]fishing practices,

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pollution and ocean acidification

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weaken coral [br]or even kill it altogether?

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Exactly what you might think.

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The loss of this keystone species[br]leaves its dependents at a loss, too,

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threatening the entire fabric of the reef.

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Ecosystem, species[br]and genetic diversity

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together form the complex tangled weave[br]of biodiversity

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that is vital for the survival [br]of organisms on Earth.

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We humans are woven [br]into this biodiversity, too.

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When just a few strands are lost,

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our own well-being is threatened.

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Cut too many links,[br]and we risk unraveling it all.

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What the future brings is unpredictable,

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but biodiversity can give [br]us an insurance policy,

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Earth's own safety net [br]to safeguard our survival.