Symbiosis: A surprising tale of species cooperation - David Gonzales

364,875 views ・ 2012-03-14

TED-Ed


Please double-click on the English subtitles below to play the video.

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Are you familiar with the word symbiosis?
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It's a fancy term for a partnership between two different species,
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such as bees and flowers.
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In a symbiosis, both species depend on each other.
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I want to tell you about a remarkable symbiosis
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between a little bird, the Clark's nutcracker,
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and a big tree, the whitebark pine.
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Whitebark grow in the mountains of Wyoming, Montana
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and other western states.
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They have huge canopies and lots of needles,
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which provide cover and shelter for other plants and animals,
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and whitebark feed the forest.
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Their cones are packed with protein.
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Squirrels gnaw the cones from the upper branches
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so they fall to the ground,
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and then race down to bury them in piles, or middens.
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But they don't get to keep all of them;
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grizzlies and black bears love finding middens.
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But there's more to a symbiosis than one species feeding another.
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In the case of the Clark's nutcracker, this bird gives back.
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While gathering its seeds, it also replants the trees.
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Here's how it works: using her powerful beak,
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the nutcracker picks apart a cone in a treetop,
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pulling out the seeds.
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She can store up to 80 of them in a pouch in her throat.
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Then she flies through the forest
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looking for a place to cache the seeds
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an inch under the soil in piles of up to eight seeds.
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Nutcrackers can gather up to 90,000 seeds in the autumn,
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which they return for in the winter and spring.
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And these birds are smart.
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They remember where all those seeds are.
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They even use landmarks on the landscape --
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trees, stumps, rocks --
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to triangulate to caches buried deep under the snow.
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What they don't go back and get, those seeds become whitebark.
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This symbiosis is so important to both species
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that they've changed, or evolved, to suit each other.
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Nutcrackers have developed long, tough beaks
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for extracting seeds from cones,
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and whitebarks' branches all sweep upwards
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with the cones at the very ends,
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so they can offer them to the nutcrackers as they fly by.
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That's a symbiosis:
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Two species cooperating to help each other for the benefit of all.
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