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Lichen: A Rock Crust Made by Two Partners

6th grade nonfiction passage about lichens on rocks: 222 words, six questions, an answer key and vocabulary.

6th grade nonfiction lichens on rocks 222 words

Lichen: A Rock Crust Made by Two Partners

Gray-green crusts, orange patches and tufts that look like tiny antlers: these are lichens, and you can find them on rocks, fences, gravestones and tree bark. A lichen looks like a single plant, but it is actually a partnership between two kinds of living things.

One partner is a fungus. The other is an alga, or sometimes a type of bacteria that can use sunlight. The fungus forms the body of the lichen, a tough mat that holds water and shelters the partner inside. The alga lives within that mat and makes sugar from sunlight, the same way a green leaf does. The fungus gets a share of the sugar. In return, it gives the alga a safe home that stays damp.

Because of this teamwork, lichens can live in places where little else can. They grow on bare rock, where there is no soil at all. Over very long stretches of time, the acids they make slowly crumble the surface, which helps start the soil that later plants will use.

Lichens are also slow. Some grow less than a few millimeters a year. Many of them soak up whatever is in the air and rain, so scientists often watch which lichens are present to learn about air quality. A tree covered in healthy lichens usually stands in fairly clean air.

Questions

  1. What two kinds of living things make up most lichens? in the text

  2. What does the alga make for the partnership? in the text

  3. What does the fungus give the alga in return? in the text

  4. How do lichens help start soil on bare rock? in the text

  5. Why does the writer say a lichen only looks like a single plant? think about it

  6. Why might scientists study lichens to learn about air quality? think about it

Words to know

lichen
a living partnership of a fungus and an alga
alga
a simple living thing that makes food from sunlight, often found in water
partnership
a relationship where two sides work together
crumble
to break into small pieces
tufts
small bunches of threads or hairs growing together
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One passage, three levels

The same topic and facts written three ways, so a mixed class can read and talk about one text. Each group’s sheet shows only a shape; the key says which is which.

● Easier · 193 words · Flesch-Kincaid grade 2.7

Gray-green crusts. Orange patches. Tufts like tiny antlers. These are lichens. You can find them on rocks, fences and tree bark. A lichen looks like one plant. But it is two kinds of living things that live together.

One partner is a fungus. The other is an alga. Sometimes it is a kind of bacteria that can use sunlight. The fungus makes the body of the lichen. It is a tough mat that holds water. The alga lives inside the mat. It makes sugar from sunlight, like a green leaf. The fungus gets some of the sugar. The alga gets a safe home that stays damp.

Because of this teamwork, lichens live where little else can. They grow on bare rock with no soil. Over a very long time, the acids they make slowly crumble the rock. This helps start the soil that later plants will use.

Lichens grow slowly. Some grow only a few millimeters a year. Many soak up what is in the air and rain. So scientists watch which lichens grow in a place to learn about the air. A tree with healthy lichens usually has fairly clean air.

▲ This passage · 222 words · Flesch-Kincaid grade 6.1

Gray-green crusts, orange patches and tufts that look like tiny antlers: these are lichens, and you can find them on rocks, fences, gravestones and tree bark. A lichen looks like a single plant, but it is actually a partnership between two kinds of living things.

One partner is a fungus. The other is an alga, or sometimes a type of bacteria that can use sunlight. The fungus forms the body of the lichen, a tough mat that holds water and shelters the partner inside. The alga lives within that mat and makes sugar from sunlight, the same way a green leaf does. The fungus gets a share of the sugar. In return, it gives the alga a safe home that stays damp.

Because of this teamwork, lichens can live in places where little else can. They grow on bare rock, where there is no soil at all. Over very long stretches of time, the acids they make slowly crumble the surface, which helps start the soil that later plants will use.

Lichens are also slow. Some grow less than a few millimeters a year. Many of them soak up whatever is in the air and rain, so scientists often watch which lichens are present to learn about air quality. A tree covered in healthy lichens usually stands in fairly clean air.

■ Harder · 229 words · Flesch-Kincaid grade 8

Gray-green crusts, orange patches and tufts resembling miniature antlers: these are lichens, and they can be discovered on rocks, fences, gravestones and tree bark. A lichen appears to be a single plant, yet it is in fact a partnership between two different kinds of living things.

One partner is a fungus. The other is an alga, or occasionally a type of bacteria that is able to use sunlight. The fungus forms the body of the lichen, a tough mat that retains water and shelters the partner within. The alga lives inside that mat and manufactures sugar from sunlight, just as a green leaf does. The fungus receives a share of the sugar. In exchange, it provides the alga with a safe home that remains damp.

Thanks to this teamwork, lichens can survive in places where very little else can. They grow on bare rock, where there is no soil whatsoever. Over extremely long stretches of time, the acids they produce gradually crumble the surface, which helps to begin the soil that later plants will depend upon.

Lichens are also remarkably slow. Some grow less than a few millimeters in a year. Many absorb whatever is present in the air and rain, so scientists often observe which lichens are growing in order to learn about air quality. A tree blanketed in healthy lichens generally stands in fairly clean air.

Download as one PDF

How to use it

  1. Press Read it big (or B) to put the text on the projector, or Full screen (F) to fill the whole screen.
  2. Ask the questions one at a time and use Show answer when the class has decided. A shows or hides every answer.
  3. Print student copy for the class, or Print with answers for yourself.

Ideas for class

  • Before reading, put lichen, alga, partnership, crumble and tufts on the board with their meanings from the Words to know section and have students predict what the text will be about.
  • Read it aloud once while students follow along, then have them reread it alone or with a partner. At a calm 100 words a minute it takes about 2 minutes to read aloud.
  • Use the Read it big button (or B) to put the text on the projector, and Show answer on one question at a time so the class commits to an answer first.
  • Question 5 asks the reader to infer. Ask students to point to the words in the passage that led them to their answer.
  • Ask students to write one question the passage did not answer, then look for the answer in a book or on a classroom screen.
  • Print the student copy for independent work and keep the answer-key copy for yourself.

Related

Questions

What reading level is "Lichen: A Rock Crust Made by Two Partners"?

It was written for 6th grade. It has 222 words and works out to a Flesch-Kincaid grade level of about 6.1. That is a formula's estimate from sentence length and syllables, and it is not a Lexile or a guided reading level, so check it against your students.

What do the questions ask?

There are six. 4 ask for something the text says directly and 2 ask the reader to work something out from clues. Each has an answer in the key, and the answers are written as a teacher would accept them, not as the only possible wording.

How long does it take to read?

About 2 minutes read aloud at 100 words a minute. For a one-minute fluency check, paste it into the fluency timer and use the word count.

Can I print it?

Yes. Print student copy gives the passage, the questions with lines to write on, and the word meanings. Print with answers gives the same page with the answers filled in. Both are made in your browser.

Is this passage from a published book?

No. It was written for Peabody Teach, so there is no book to buy and no login to read it.

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