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  • Have you ever heard of lichen?

  • It doesn’t get the same attention that bigger, more exciting living things get -- like elephants,

  • or sharks, or giant redwood trees.

  • But it’s one of the coolest things that youre likely to find on your next walk

  • in the woods -- or even in your own back yard!

  • Lichen is a tiny living thing, or organism, that grows outdoors, attaching itself, most

  • of the time, to rocks, trees and soil.

  • This small but colorful organism really likes moist areas, which is why you can find it

  • where water runs down rocks, on the bark of damp trees, and on the wet ground.

  • But here’s a surprise---lichen is actually two different organisms that live together

  • to help each other out.

  • It’s actually both a fungus and an algae.

  • You may have seen fungus on the bottom of your old bread at the bottom of the bag.

  • Gross, I know, sorry. But that fuzzy green mold is a kind of fungus, and mushrooms are

  • part of a fungus, too.

  • As for algae, you mightve seen that on the inside of your fish tank, or wherever

  • there’s still water, like a pond.

  • In lichen, fungus and algae work together in a relationship called symbiosis. A symbiotic

  • relationship is where two organisms help each other survive, with each of them getting something

  • out of the relationship.

  • Both the fungus and the algae bring special skills to this party. The fungus is bigger

  • and has a stronger body than algae, so it gives the lichen its shape.

  • But the algae has another role. The algae brings home the bacon...by which, I mean,

  • it makes food.

  • Not bacon.

  • Like many other plants, algae can make food from sunlight. It uses a process called photosynthesis

  • to capture energy from the sun to make sugars that it uses for energy.

  • Since the fungus can’t do this on its own, it pairs up with the algae to help get a steady

  • supply of food.

  • And while algae can survive on its own, wherever there’s water and light, pairing up with

  • the fungus allows it to grow in all kinds of different landscapes, like moist, sandy

  • places, wooded forests and rocks!

  • Once you learn how to spot it, it can be pretty easy to find in all sorts of places.

  • It can be blue, green or red. Or yellow! Or even orange! The color of lichen depends on

  • what type of fungus and algae are working together.

  • But there are three main types to look for. The first kind is leafy like lettuce. But

  • don’t eat it!

  • The second kind can grow to look like little teacups, or the wispy strands of an old man’s

  • beard. You may have seen this type swaying in the wind on tree branches.

  • And the last type is calledcrust lichen.” It’s colorful and flat - you can find them

  • on rocks. And it makes the rocks look like they have spots!

  • Whatever the shape and color, lichen is very diverse and it's also very delicate. It grows

  • extremely slowly, so if you happen to see some while youre on a hike, try not to

  • step on it!

  • While it may be small, lichen is an important part of nature, because it provides a home

  • for little critters like spiders and small insects.

  • And here’s a fun fact! - Lichen usually grows where the air is fresh and clean, which

  • is why you can find them out in natural areas, like in forests and around lakes, but not

  • necessarily near highways or in the city.

  • So if youre out on a walk with your friends or family, and you see a little sprig of lichen

  • on a tree or a rock, take a deep breath of fresh air! Ahhh.

  • Thanks for watching Sci Show Kids. See you next time.

Have you ever heard of lichen?

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B2 中高級

地衣。一物兩用 (Lichen: Two Living Things In One)

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    Jack 發佈於 2021 年 01 月 14 日
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