The wild world of carnivorous plants - Kenny Coogan

2,247,208 views ・ 2019-04-11

TED-Ed


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

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Little do they know it,
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but these six creatures are each about to experience a very unusual death.
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One-by-one,
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they will fall prey to the remarkable, predatory antics of...
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a carnivorous plant.
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Around the world there are more than 600 plant species
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that supplement a regular diet of sunlight, water, and soil
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with insects, microbes, or even frogs and rats.
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Scientists believe that carnivory in plants evolved separately
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at least six times on our planet,
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suggesting that this flesh-munching adaptation
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holds a major benefit for plants.
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Carnivorous plants tend to grow in places with highly acidic soil,
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which is poor in crucial nutrients like nitrogen, phosphorus, and potassium.
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In these hostile conditions,
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plants that are able to lure, trap, and digest prey
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have an advantage over those that rely on soil for their nutrients.
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Take this inhospitable bog,
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where pitcher plants reign supreme.
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Drawn to the pitcher’s vivid colors and alluring scent,
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the fly closes in and slurps its nectar.
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But this pitcher species has an ingredient called coniine in its nectar,
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a powerful narcotic to insects.
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As the coniine takes effect,
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the fly grows sluggish, stumbles, and falls down the funnel
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into a pool of liquid at the base,
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where he drowns.
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Enzymes and bacteria in the liquid slowly break his body down
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into microscopic particles the pitcher plant can consume through its leaves.
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Occasionally,
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larger prey also tumbles into the fatal funnel of the pitcher plant.
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The second victim faces off with the sticky sundew plant.
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The sundew’s tiny leaves are equipped with a viscous secretion called mucilage.
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The ant is swiftly trapped in this goo.
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As she struggles, enzymes begin to digest her body.
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Special tentacles sense her movement and curl around her,
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clenching her in their suffocating grip.
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Once she asphyxiates,
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which can happen in under an hour,
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the tentacles unfurl again to snare their next victim.
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Two down, four to go.
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The next target meets his end underground,
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in the coils of the corkscrew plant.
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He enters the roots through a tiny slit in search of food.
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But inside, he quickly loses his way through the tangled labyrinth.
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A forest of curved hairs prevents his escape,
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guiding him into a central chamber with flesh-digesting enzymes
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and deadly low levels of oxygen.
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In the murky depths of a nearby pond,
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a tadpole unwittingly swims into the path of the bladderwort,
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the speediest of all carnivorous plants.
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She treads on the bladderwort’s trigger,
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and in milliseconds,
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a trapdoor swings open and sucks her in.
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Trapped half in and half out,
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she struggles to free herself
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while the part of her body inside the plant gets digested.
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Over the next few hours,
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her writhing sets the trap off repeatedly,
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each time bringing her deeper into the plant
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to be digested alive bit by bit.
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Meanwhile, this beetle is bewitched by sweet-smelling nectar.
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The scent draws him closer and closer
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until he lands on the leaves of the world’s most infamous carnivorous plant.
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His landing triggers tiny hairs on the surface of the leaves,
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and the jaws of the venus fly trap snap shut around him.
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The spikes interlock to seal his fate.
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Once closed,
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the leaves act like an external stomach that digests the beetle’s soft tissues.
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When they open again a few days later,
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only the dry husk of his exoskeleton remains.
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The mayfly is the last creature standing.
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As she approaches the butterwort plant,
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she heads for the flowers that wave high above the plant’s globs of adhesive goo.
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She alights on the petals, drinks the nectar, and takes off unscathed.
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These long flower stalks keep certain insects away from the carnivore’s traps—
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a way of separating pollinators from food.
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Off the mayfly buzzes to live a long and fruitful life–
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oh.
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