reading for how a leaf works

Reading forInformation

548 unit 5: author’s purpose

What’s the Connection?You just read a rather poetic yet scientific description of why leaves turn color in the fall. Now you will learn from a few well-designed graphic aids why leaves are green in the first place.

Standards Focus: Interpret Graphic AidsA graphic aid is a visual illustration of a verbal statement. Graphic aids include photographs, diagrams, maps, and equations. Well-made graphics clarify the text they accompany, making complex information easier to understand. Graphics may also emphasize details that the text does not. Determining which information comes from graphics, which from text, and which from both, can help you more fully comprehend the process. You can use these guidelines to interpret and evaluate most graphic aids:

• Read the title, headings, and captions first to get the main idea. • On maps and complex graphic aids, look for a key or legend to see

how colors and symbols are used.• Use the obvious meanings of symbols such as arrows to help you

read the visual information. • Pay attention to labels that identify specific details.• Study the information in the graphic, looking for patterns or basic

concepts.• Ask yourself, “Is this graphic clear? Does it help explain the text or

add visual appeal?”

As you read the pages that follow, complete a chart like the one shown. State in your own words what each graphic aid shows.

Type of Graphic Aid What It Shows

Magnified photograph of a leaf cell

Cutaway diagram of a chloroplast

Schematic diagram of photosynthesis

Chemical equation for photosynthesis

Cutaway diagram of a leaf

Use with “Why Leaves Turn Color in the Fall,”

page 540.

How a Leaf Works Textbook Diagrams

Use with “Why Leaves

The stealth of autumn catches one unaware. Was that a goldfinch perching

in the early September woods, or just the first turning leaf? A red-winged

blackbird or a sugar maple closing up shop for the winter? Keen-eyed as

leopards, we stand still and squint hard, looking for signs of movement. Early-

morning frost sits heavily on the grass, and turns barbed wire into a string of

stars. On a distant hill, a small square of yellow appears to be a lighted stage.

At last the truth dawns on us: Fall is staggering in, right on schedule, with its

baggage of chilly nights, macabre holidays, and spectacular, heart-stoppingly

beautiful leaves. Soon the leaves will start cringing on the trees, and roll up

in clenched fists before they actually fall off. Dry seedpods will rattle like tiny

gourds. But first there will be weeks of gushing color so bright, so pastel, so

confettilike, that people will travel up and down the East Coast just to stare at

it—a whole season of leaves. a

Where do the colors come from? Sunlight rules most living things with its

golden edicts. When the days begin to shorten, soon after the summer solstice

on June 21, a tree reconsiders its leaves. All summer it feeds them so they

can process sunlight, but in the dog days of summer the tree begins pulling

nutrients back into its trunk and roots, pares down, and gradually chokes off

its leaves. A corky layer of cells forms at the leaves’ slender petioles,1 then scars

over. Undernourished, the leaves stop producing the pigment chlorophyll,

and photosynthesis2 ceases. Animals can migrate, hibernate, or store food to

prepare for winter. But where can a tree go? It survives by dropping its leaves,

1. petioles: the stalks of leaves.

2. chlorophyll . . . photosynthesis: Chlorophyll is the green pigment in plants that is necessary for

photosynthesis, the process by which plants use sunlight, water, and carbon dioxide to produce food.

10

20

diane ackerman

WhyLeaves

Turn Color

in theFall

stealth (stDlth) n. a concealed manner of acting

edict (CPdGkt’) n. a command issued by an authority

a AUTHOR’S PURPOSE What seems to be Ackerman’s purpose in the first paragraph? Support your answer with

specific details.

Language Coach

Denotations/Connotations The feelings and ideas associated with a word

are its connotations. Staggering and toddling

both mean “moving unsteadily.” Toddling suggests youth; what does staggering (line 7)

suggest?


RI 4

RI 4 Determine the technical meaning of words and phrases used in a text. RI 7 Analyze various accounts of a subject told in different mediums, determining which details are emphasized in each account.

NA_L10PE-u05s3-rl3Lea.indd 548NA_L10PE-u05s3-rl3Lea.indd 548 12/25/10 6:02:59 PM12/25/10 6:02:59 PM

Reading for Information

reading for information 549 reading fo

a

INTERPRET GRAPHIC AIDSScience textbooks often include photographs of structures magnified to many times their actual size. What does this photo of a leaf cell show you about chloroplasts?

c

INTERPRET GRAPHIC AIDSA schematic diagram uses lines, symbols, and words to help readers picture processes or objects not normally seen. What do the arrows in this schematic diagram communicate?

a

c

b

TECHNICAL MEANINGSMany English words are derived from Greek root words. The root chloro- comes from the Greek chlóros, meaning “pale green.” English words containing the root chloro- are used in many biological terms. Reread the text under step 2. What words contain chloro-? What do you think these words mean? (Hint: -plast means “to form” and -phyll means “leaf.”)

b

RI 4


Inside a Leaf

The leaf is an organ that produces sugars.It is made up of different types of cellsand tissues.

Cells at the surface producea waxy cuticle that keepsthe leaf from losing water.

Carbon dioxide, oxygen,and water vapor moveinto and out of the leafthrough stomata.

Most chloroplasts arelocated in cells of theupper layer of the leaf.

Xylem transports water and nutrients up from the roots.

Phloem transports energy-richcompounds made in the leafdown to other parts of the plant.


d

INTERPRET GRAPHIC AIDSA cutaway diagram shows an object with the outer part removed to reveal the interior. Notice the different layers of cells in this cutaway diagram of a leaf. Where are the chloroplasts located? What do they look like?

d


After Reading Reading for Information

reading for information 551

Comprehension1. Recall Where does photosynthesis take place?

2. Recall What does a plant do with the products of photosynthesis?

3. Paraphrase Review the equation at the bottom of page 549.Paraphrase this equation.

Text Analysis4. Interpret Graphic Aids What parts of a leaf are shown in the cutaway

diagram on page 550, titled “Inside a Leaf”? What are their different functions?

5. Compare Texts How would you compare the experience of reading the graphic aids with the experience of reading “Why Leaves Turn Color in the Fall”? Which source did you find more informative? Explain your answer.

Read for Information: Use Information from Multiple Sources

writing promptOn the basis of the information in the textbook diagrams and Diane Ackerman’s essay, explain (1) the process of photosynthesis, (2) the reason leaves are green in summer, and (3) the reason leaves turn color in the fall. Define scientific terms in your explanation.

To respond to this prompt, you will need to synthesize information from multiple sources having to do with photosynthesis and the color of leaves. Then you will need to paraphrase this information. Following these steps can help:1. Review the chart you created as you read, noting what the schematic

diagram of photosynthesis showed you.2. Review the diagram labeled “Inside a Leaf,” looking for more details you

could add to your explanation. Jot them down.3. Review Diane Ackerman’s essay,

identifying and taking notes on passages that discuss photosynthesis, the green color of leaves, and the process of color change.

4. Using your notes from all three sources, describe the three topics in the order listed in the prompt.

Notes from Source 1

Notes from Source 3

Notes from Source 2 Your Paper

RI 7 Analyze various accounts of a subject told in different mediums, determining which details are emphasized in each account. W 2d Use domain-specific vocabulary to manage the complexity of the topic. W 8 Gather relevant information from multiple print sources.


reading for how a leaf works

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