TED 音読練習

共生とは何か

出典：TED Ed



Are you familiar with the word symbiosis?

symbiosis … 共生

It's a fancy term for a partnership between two different species, such as bees and flowers.

fancy term … しゃれた用語、凝った用語

In a symbiosis, both species depend on each other.

I want to tell you about a remarkable symbiosis between a little bird, the Clark's Nutcracker, and a big tree, the Whitebark Pine.

Clark's Nutcracker … ハイイロホシガラス
Whitebark Pine … アメリカシロゴヨウ（松の一種）

Whitebark grow in the mountains of Wyoming, Montana and other western states.

They have huge canopies and lots of needles, which provide cover and shelter for other plants and animals, and Whitebark feed the forest.

canopy … 林冠（樹林の枝葉による屋根のような覆い）

Their cones are packed with protein.

cone … 球果（松かさのような実）

Squirrels gnaw the cones from the upper branches so they fall to the ground, and then race down to bury them in piles, or middens.

squirrel … リス
gnaw [nɔ́ː] … かじる
midden … （動物が集めた種子や葉などの）山

But they don't get to keep all of them; grizzlies and black bears love finding middens.

But there's more to a symbiosis than one species feeding another.

there is more to A than B … AにはB以上のことがある

In the case of the Clark's Nutcracker, this bird gives back.

give back … お返しをする

While gathering its seeds, it also replants the trees.

Here's how it works: using her powerful beak, the Nutcracker picks apart a cone in a treetop, pulling out the seeds.

beak … くちばし

She can store up to 80 of them in a pouch in her throat.

Then she flies through the forest, looking for a place to cache the seeds an inch under the soil in piles of up to eight seeds.

cache … 貯蔵する、隠す

Nutcrackers can gather up to 90,000 seeds in the autumn, which they return for in the winter and spring.

And these birds are smart.

They remember where all those seeds are.

They even use landmarks on the landscape -- trees, stumps, rocks -- to triangulate to caches buried deep under the snow.

triangulate … 三角測量する

What they don't go back and get, those seeds become Whitebark.

This symbiosis is so important to both species that they've changed, or evolved, to suit each other.

Nutcrackers have developed long, tough beaks for extracting seeds from cones, and Whitebarks' branches all sweep upwards with the cones at the very ends, so they can offer them to the Nutcrackers as they fly by.

sweep … 長く延びる

Now, that's a symbiosis: Two species cooperating to help each other for the benefit of all.