Download What Is a Plant?

Introduction to Plants
12
Compression guide:
To shorten instruction
because of time limitations,
omit Section 4.
Chapter Planning Guide
OBJECTIVES
PACING • 90 min
pp. 298–303
LABS, DEMONSTRATIONS, AND ACTIVITIES
• Identify four characteristics that all plants share.
• Describe the four main groups of plants.
• Explain the origin of plants.
PACING • 45 min
pp. 304–307
Section 2 Seedless Plants
• List three nonvascular plants and three seedless
vascular plants.
• Explain how seedless plants are important to the
environment.
• Describe the relationship between seedless vascular
plants and coal.
PACING • 45 min
pp. 308–313
Section 3 Seed Plants
• Describe three ways that seed plants differ from
seedless plants.
• Describe the structure of seeds.
• Compare angiosperms and gymnosperms.
• Explain the economic and environmental importance
of gymnosperms and angiosperms.
PACING • 90 min
pp. 314–321
Section 4 Structures of Seed Plants
• List three functions of roots and three functions
of stems.
• Describe the structure of a leaf.
• Identify the parts of a flower and their functions.
Parent Letter ■
Student Edition on CD-ROM
Chapter Starter Transparency*
Guided Reading Audio CD ■
Brain Food Video Quiz
SE Start-up Activity, p. 299 ◆ g
OSP
CD
TR
CD
VID
TE Activity Water Travel in Plants, p. 300 g
TE Group Activity Baby-Powder Cuticle, p. 301 g
TE Activity Life Cycles, p. 301 a
OSP Lesson Plans (also in print)
TR Bellringer Transparency*
TR L40 The Main Groups of Plants*
CRF SciLinks Activity* g
CD Interactive Explorations CD-ROM
Shut Your Trap! g
CD Science Tutor
Chapter Opener
Section 1 What Is a Plant?
TECHNOLOGY RESOURCES
TE
SE
CRF
TE
SE
Activity Identifying Plant Parts, p. 304 ◆ g
Quick Lab Moss Mass, p. 305 g
Datasheet for Quick Lab*
Connection Activity Real World, p. 305 g
Science in Action Math, Social Studies, and Language
Arts Activities, pp. 328–329 g
Activity Seed Types, p. 308 g
Quick Lab Dissecting Seeds, p. 309 g
Group Activity Seed Dispersal, p. 309 ◆ g
Connection Activity Earth Science, p. 310 a
Skills Practice Lab Travelin’ Seeds, p. 776 ◆ g
EcoLabs & Field Activities The Case of the Ravenous
Radish* ◆ g
LB Long-Term Projects & Research Ideas
Plant Planet a
TE
SE
TE
TE
SE
LB
TE
TE
TE
TE
TE
SE
Demonstration Roots, p. 314 ◆ g
Group Activity Root Growth, p. 315 ◆ b
Activity Stem Functions, p. 316 b
Connection Activity History, p. 316 a
Activity Analyzing Tree Rings, p. 317 g
School-to-Home Activity Looking at Leaves,
TE
SE
SE
LB
Group Activity Leaf Collecting, p. 318 g
Model-Making Lab Build a Flower, p. 322 ◆ g
Skills Practice Lab Leaf Me Alone!, p. 774 g
Whiz-Bang Demonstrations Inner Life of a Leaf* ◆ a
PACING • 90 min
CHAPTER REVIEW, ASSESSMENT, AND
STANDARDIZED TEST PREPARATION
CRF
SE
CRF
CRF
SE
CRF
CRF
OSP
Vocabulary Activity* g
Chapter Review, pp. 324–325 g
Chapter Review* ■ g
Chapter Tests A* ■ g, B* a, C* s
Standardized Test Preparation, pp. 326–327 g
Standardized Test Preparation* g
Performance-Based Assessment* g
Test Generator, Test Item Listing
297A
Chapter 12 • Introduction to Plants
p. 318 g
OSP Lesson Plans (also in print)
TR Bellringer Transparency*
CD Science Tutor
OSP Lesson Plans (also in print)
TR Bellringer Transparency*
TR L41 Two Classes of Angiosperms*
TE Internet Activity, p. 312 g
CD Science Tutor
OSP Lesson Plans (also in print)
TR Bellringer Transparency*
TR L42 The Structures of a Root*
TR L43 Cross Section of a Herbaceous
Stem; Cross Section of a Woody
Stem*
TR L44 The Structure of a Leaf*
TR LINK TO PHYSICAL SCIENCE P92 The
Electromagnetic Spectrum*
TR L45 The Structure of a Flower*
VID Lab Videos for Life Science
CD Science Tutor
Online and Technology Resources
Visit go.hrw.com for
access to Holt Online
Learning, or enter the
keyword HL7 Home
for a variety of free
online resources.
This CD-ROM package includes:
• Lab Materials QuickList Software
• Holt Calendar Planner
• Customizable Lesson Plans
• Printable Worksheets
•
•
•
•
ExamView ® Test Generator
Interactive Teacher’s Edition
Holt PuzzlePro®
Holt PowerPoint® Resources
KEY
SE Student Edition
TE Teacher Edition
CRF
OSP
LB
TR
Chapter Resource File
One-Stop Planner
Lab Bank
Transparencies
SKILLS DEVELOPMENT RESOURCES
SS
MS
CD
VID
Science Skills Worksheets
Math Skills for Science Worksheets
CD or CD-ROM
Classroom Video/DVD
IT
*
◆
■
SECTION REVIEW AND ASSESSMENT
SE Pre-Reading Activity, p. 298 g
OSP Science Puzzlers, Twisters & Teasers g
Interactive Textbook
Also on One-Stop Planner
Requires advance prep
Also available in Spanish
STANDARDS
CORRELATIONS
CORRELATION
National Science
Education Standards
SAI 1, 2; LS 1c, 3a
CRF
IT
CRF
SE
SE
TE
Directed Reading A* ■ b, B* s
Interactive Textbook* Struggling Readers
Vocabulary and Section Summary* ■ g
Reading Strategy Reading Organizer, p. 300 g
Connection to Social Studies Countries and Crops, p. 301 g
Support for English Language Learners, p. 301
SE
TE
TE
TE
SE
CRF
Reading Checks, pp. 301, 302, 303 g
Reteaching, p. 302 b
Quiz, p. 302 g
Alternative Assessment, p. 302 a
Section Review,* p. 303 ■ g
Section Quiz* ■ g
UCP 1, 2, 4; SAI 1, 2; ST 2;
HNS 2; LS 1a, 2b, 4c, 5a
CRF
IT
CRF
SE
TE
TE
SE
Directed Reading A* ■ b, B* s
Interactive Textbook* Struggling Readers
Vocabulary and Section Summary* ■ g
Reading Strategy Paired Summarizing, p. 304 g
Support for English Language Learners, p. 305
Inclusion Strategies, p. 306 ◆
Connection to Language Arts Selling Plants, p. 307 g
SE
TE
TE
TE
TE
SE
CRF
Reading Checks, pp. 305, 307 g
Reteaching, p. 306 b
Quiz, p. 306 g
Alternative Assessment, p. 306 g
Homework, p. 306 g
Section Review,* p. 307 ■ g
Section Quiz* ■ g
UCP 1, 2, 3, 4; SAI 1; LS 1a, 1c,
2b, 5c
CRF
IT
CRF
SE
TE
TE
SS
CRF
CRF
Directed Reading A* ■ b, B* s
Interactive Textbook* Struggling Readers
Vocabulary and Section Summary* ■ g
Reading Strategy Reading Organizer, p. 308 g
Inclusion Strategies, p. 311
Support for English Language Learners, p. 311
Science Skills Science Writing* g
Reinforcement Worksheet Classifying Plants* b
Reinforcement Worksheet Drawing Dicots* b
SE Reading Checks, pp. 308, 309, 311,
312, 313 g
TE Homework, p. 310 a
TE Reteaching, p. 312 b
TE Quiz, p. 312 g
TE Alternative Assessment, p. 312 a
SE Section Review,* p. 313 ■ g
CRF Section Quiz* ■ g
CRF
IT
CRF
SE
SE
TE
SS
CRF
Directed Reading A* ■ b, B* s
Interactive Textbook* Struggling Readers
Vocabulary and Section Summary* ■ g
Reading Strategy Mnemonics, p. 314 g
Math Practice Practice with Percentages, p. 315 g
Support for English Language Learners, p. 318
Science Skills Taking Notes* g
Critical Thinking The Voodoo Lily* a
SE
TE
SE
TE
TE
TE
CRF
Reading Checks, pp. 315, 316, 318, 320 g
Homework, p. 319 g
Section Review,* p. 321 ■ g
Reteaching, p. 320 b
Quiz, p. 320 g
Alternative Assessment, p. 320 g
Section Quiz* ■ g
Classroom
Videos
www.scilinks.org
Maintained by the National
Science Teachers Association.
See Chapter Enrichment pages
that follow for a complete list
of topics.
Check out Current Science
articles and activities by
visiting the HRW Web site
at go.hrw.com. Just type
in the keyword HL5CS12T.
UCP 1, 2, 4; SAI 1; SPSP 4; LS
1a, 1d, 2b, 2c, 2d, 4b, 4c, 4d,
5b; LabBook: UCP 2, 5;
SAI 1, 2; LS 2b
• Lab Videos demonstrate
the chapter lab.
• Brain Food Video Quizzes
help students review the
chapter material.
Classroom
CD-ROMs
• Guided Reading Audio CD
(Also in Spanish)
• Interactive Explorations
• Virtual Investigations
• Visual Concepts
• Science Tutor
UCP 1, 2, 4; SAI 1; SPSP 5;
LS 1a, 1d, 2b, 3d, 4c, 5b;
Chapter Lab: UCP 1, 2, 5; SAI 1,
2; ST 2; HNS 1, 2; LS 1a, 2a, 2b;
LabBook: UCP 1, 5; SAI 1
Holt Lab Generator
CD-ROM
Search for any lab by topic, standard,
difficulty level, or time. Edit any lab
to fit your needs, or create your own
labs. Use the Lab Materials QuickList
software to customize your lab
materials list.
Chapter 12 • Chapter Planning Guide
297B
12
Chapter Resources
Visual Resources
TEACHING TRANSPARENCIES
Introduction to Plants
BELLRINGER TRANSPARENCY
Nonvascular plants
Mosses, liverworts,
and hornworts
Section: What Is a Plant?
There are four major types of plants. Try to identify
all four types, and give at least two examples for
each one. Do all four types of plants grow near your
home? Where will you most likely find each type
of plant?
Write your responses in your science journal.
Bundles of
vascular tissue
are in a ring.
TEACHING TRANSPARENCY
Leaf cells are arranged in layers. These
layers allow the leaf to work efficiently.
Cuticle
Upper epidermis
TEACHING TRANSPARENCY
Flowering
Angiosperms
Seed plants
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Palisade layer
Spongy layer
Lower epidermis
Xylem
Phloem
Guard cells
CONCEPT MAPPING
TRANSPARENCY
TEACHING TRANSPARENCIES
TEACHING TRANSPARENCY
Phloem
Visible light is only a small band of the electromagnetic spectrum.
Radio waves have the longest wavelengths, and gamma rays
have the shortest wavelengths.
Xylem
Microwaves
Xylem
Phloem
Radio waves
A root absorbs water and minerals, which move
into the xylem. Growth occurs at the tip of a
root. The root cap releases a slimy substance
that helps the root grow through soil.
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Buttercups are just one plant that has herbaceous
stems. Wildflowers and many vegetables have soft,
thin, and flexible stems.
Infrared
Root
cap
Visible
TEACHING TRANSPARENCY
Growth
ring
Stigma
Style
Ovary
Anther
Filament
Sepal
Pistil
Phloem
CONCEPT MAPPING TRANSPARENCY
Use the following terms to complete the concept map below:
angiosperms, vascular, plants, sporophyte, nonvascular, pollen,
gametophyte, xylem
which produces
can be
classified as
which produces
and
include
spores
nonflowering
flowering
gymnosperms
which contain
Xylem
Ovule
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Introduction to Plants
have two life stages
which include the
TEACHING TRANSPARENCY
Stamen
Ovary
Gamma rays
Style
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Petal
Stigma
Ovule
X rays
Some plants, such as these trees, have woody
stems. Plants that have woody stems usually live
for many years. People can use growth rings to
estimate the age of a plant.
The Structure of a Flower
The stamens, which produce pollen, and the pistil,
which produces eggs, are surrounded by the petals
and the sepals.
Ultraviolet
Cross Section of a Woody Stem
Introduction to Plants
Studying Space
TEACHING TRANSPARENCY
Cross Section of a Herbaceous Stem
The Electromagnetic Spectrum
Introduction to Plants
The Structures of a Root
Vascular tissue
Cuticle
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Stoma
Introduction to Plants
Two cotyledons
(seed leaves)
Bundles of
vascular tissue
are scattered.
Vascular plants
Nonflowering
Write your answers in your science journal.
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Flower
parts in
fours or
fives
One cotyledon
(seed leaf)
The Structure of a Leaf
Gymnosperms
bark. They grow as tall as 35 m, and their
trunks can grow as wide as 1 m.
Since the discovery of the trees,
scientists at the Royal Botanic Gardens
in Sydney, Australia, have been planting
seeds of the Wollemi pines and growing
seedlings. Soon Wollemi pines will be
made available to gardeners so they can
transform their yards into their own
Cretaceous parks.
In this chapter, you will learn more
about the mysterious world of plants.
You will see that plants are complex
organisms that challenge our understanding of nature.
Leaves with
branching veins
Flower
parts in
threes
Seedless plants
Ferns, horsetails,
and club mosses
A lone scientist trudges through a remote
rain forest. Peering into a steep, narrow
canyon, he notices something unusual.
On closer inspection, he discovers that
it is a species of tree that has survived
from the days when Tyrannosaurus rex
and Velociraptor walked the Earth!
No, this isn’t a scene out of Jurassic
Park. This really happened in an Australian
rain forest in 1994. The scientist’s name
was David Noble. He discovered a tree
species that dates back to the Cretaceous
period, between 144 million and 65
million years ago.
The trees, called Wollemi pines, have
large, bladelike leaves and knobby brown
Dicots
Monocots
Leaves with
parallel veins
Introduction to Plants
Section: Seedless Plants
If plants can make their own food, why do people
add fertilizer to soil? What happens when you plant
crops in the same field over and over again? Does
fertilizer ever stop working?
This Really Happened!
TEACHING TRANSPARENCY
Two Classes of Angiosperms
phloem
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter: The Nature of Light
Planning Resources
PARENT LETTER
LESSON PLANS
TEACHER RESOURCE PAGE
SAMPLE
Lesson Plan
SAMPLE
Dear Parent,
TEST ITEM LISTING
TEST ITEM LISTING
The World of Science
SAMPLE
MULTIPLE CHOICE
Section: Waves
Your son's or daughter's science class will soon begin exploring the chapter entitled “The
World of Physical Science.” In this chapter, students will learn about how the scientific
Pacing
Regular Schedule:
with lab(s):2 days
without lab(s):2 days
Block Schedule:
with lab(s): 1 1/2 days
without lab(s):1 day
method applies to the world of physical science and the role of physical science in the
world. By the end of the chapter, students should demonstrate a clear understanding of the
chapter’s main ideas and be able to discuss the following topics:
Objectives
1. Relate the seven properties of life to a living organism.
2. Describe seven themes that can help you to organize what you learn about
biology.
3. Identify the tiny structures that make up all living organisms.
4. Differentiate between reproduction and heredity and between metabolism
and homeostasis.
1. physical science as the study of energy and matter (Section 1)
2. the role of physical science in the world around them (Section 1)
3. careers that rely on physical science (Section 1)
4. the steps used in the scientific method (Section 2)
5. examples of technology (Section 2)
National Science Education Standards Covered
6. how the scientific method is used to answer questions and solve problems (Section 2)
LSInter6:Cells have particular structures that underlie their functions.
7. how our knowledge of science changes over time (Section 2)
LSMat1: Most cell functions involve chemical reactions.
8. how models represent real objects or systems (Section 3)
LSBeh1:Cells store and use information to guide their functions.
9. examples of different ways models are used in science (Section 3)
UCP1:Cell functions are regulated.
10. the importance of the International System of Units (Section 4)
SI1: Cells can differentiate and form complete multicellular organisms.
PS1: Species evolve over time.
ESS1: The great diversity of organisms is the result of more than 3.5 billion years
of evolution.
11. the appropriate units to use for particular measurements (Section 4)
12. how area and density are derived quantities (Section 4)
ESS2: Natural selection and its evolutionary consequences provide a scientific
explanation for the fossil record of ancient life forms as well as for the striking
molecular similarities observed among the diverse species of living organisms.
Questions to Ask Along the Way
ST1: The millions of different species of plants, animals, and microorganisms
that live on Earth today are related by descent from common ancestors.
such as the following:
ST2: The energy for life primarily comes from the sun.
You can help your son or daughter learn about these topics by asking interesting questions
•
What are some surprising careers that use physical science?
SPSP1: The complexity and organization of organisms accommodates the need
for obtaining, transforming, transporting, releasing, and eliminating the matter
and energy used to sustain the organism.
•
What is a characteristic of a good hypothesis?
•
When is it a good idea to use a model?
SPSP6: As matter and energy flows through different levels of organization of
living systems—cells, organs, communities—and between living systems and the
physical environment, chemical elements are recombined in different ways.
•
Why do Americans measure things in terms of inches and yards instead of centimeters
and meters ?
HNS1: Organisms have behavioral responses to internal changes and to external
stimuli.
1. A limitation of models is that
a. they are large enough to see.
b. they do not act exactly like the things that they model.
c. they are smaller than the things that they model.
d. they model unfamiliar things.
Answer: B
Difficulty: I
Section: 3
Objective: 2
2. The length 10 m is equal to
a. 100 cm.
b. 1,000 cm.
Answer: B
Difficulty: I
c. 10,000 mm.
d. Both (b) and (c)
Section: 3
Objective: 2
3. To be valid, a hypothesis must be
a. testable.
b. supported by evidence.
Answer: B
Difficulty: I
c. made into a law.
d. Both (a) and (b)
Section: 3
Objective: 2 1
4. The statement "Sheila has a stain on her shirt" is an example of a(n)
a. law.
c. observation.
b. hypothesis.
d. prediction.
Answer: B
Difficulty: I
Section: 3
Objective: 2
5. A hypothesis is often developed out of
a. observations.
b. experiments.
Answer: B
Difficulty: I
c. laws.
d. Both (a) and (b)
Section: 3
Objective: 2
6. How many milliliters are in 3.5 kL?
a. 3,500 mL
b. 0.0035 mL
Answer: B
Difficulty: I
c. 3,500, 000 mL
d. 35,000 mL
Section: 3
Objective: 2
7. A map of Seattle is an example of a
a. law.
b. theory.
Answer: B
Difficulty: I
c. model.
d. unit.
Section: 3
Objective: 2
8. A lab has the safety icons shown below. These icons mean that you should wear
a. only safety goggles.
c. safety goggles and a lab apron.
b. only a lab apron.
d. safety goggles, a lab apron, and gloves.
Answer: B
Difficulty: I
Section: 3
Objective: 2
9. The law of conservation of mass says the tot al mass before a chemical change is
a. more than the total mass after the change.
b. less than the total mass after the change.
c. the same as the total mass after the change.
d. not the same as the total mass after the change.
Answer: B
Difficulty: I
Section: 3
Objective: 2
10. In which of the following areas might you find a geochemist at work?
a. studying the chemistry of rocks
c. studying fishes
b. studying forestry
d. studying the atmosphere
Answer: B
Difficulty: I
Section: 3
Objective: 2
Copyright © by Holt Rinehart and Winston All rights reserved
297C Chapter 12 • Introduction to Plants
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Introduction to Plants
Introduction to Plants
CHAPTER STARTER
The Main Groups of Plants
Introduction to Plants
BELLRINGER
TRANSPARENCIES
This CD-ROM includes all of the
resources shown here and the
following time-saving tools:
• Lab Materials QuickList
Software
• Customizable lesson plans
• Holt Calendar Planner
• The powerful
ExamView ® Test
Generator
Copyright © by Holt, Rinehart and Winston. All rights reserved.
CHAPTER STARTER
TRANSPARENCY
For a preview of available worksheets covering math and science skills,
see pages T26–T33. All of these resources are also on the One-Stop Planner®.
Meeting Individual Needs
DIRECTED READING A
Name
Class
VOCABULARY ACTIVITY
Date
Name
Class
REINFORCEMENT
Name
Date
SAMPLE
Directed Reading A
SAMPLE
Vocabulary Activity
Section: Exploring
Getting the Dirt on the Soil
THAT’S SCIENCE!
After you finish reading Chapter: [Unique Title], try this puzzle! Use the clues below
to unscramble the vocabulary words. Write your answer in the space provided.
1. How did James Czarnowski get his idea for the penguin boat, Proteus?
Explain.
1. the breakdown of rock into
smaller and smaller pieces:
AWERIGNETH
2. layer of rock lying beneath soil:
CROKDEB
3. type of crop that is planted
between harvests to reduce soil
erosion: CROVE
DIRECTED READING B
3. What do air, a ball, and a cheetah have in common?
4. action of rocks and sediment
scraping against each other and
wearing away exposed surfaces:
Name
SABRONIA
4. What is one question you will answer as you explore physical science?
Class
10. layers of soil, to a geologist:
SNORHIZO
VOCABULARY AND
SECTION SUMMARY
MATTER + AIR ➔ PHYSICAL SCIENCE
Name
9. the chemical breakdown of rocks
and minerals into new
substances: CAMILCHE
THEARIGWEN
GENERAL
2. What is unusual about the way that Proteus moves through the water?
Date
11. the uppermost layer of soil:
SPOTOIL
12. process in which rainwater carries dissolved substances from
the uppermost layers of soil to the
Date
bottom layers: HELANCIG
Class
SAMPLE
Directed Reading B
study theExploring
different forms of
Section:
and how they interact.
THAT’S SCIENCE!
and how it affects
1. How
didinJames
Czarnowski get his idea for the penguin boat, Proteus?
studied
physics.
Explain.
are
1. scientific method
7. type of reaction that occurs when
oxygen combines with iron to
form rust: oxidation
Identify the field of physical science to which each of the following descriptions
belongs by writing physics or chemistry in the space provided.
_______________________
6. way
how that
a compass
2. What is unusual about the
Proteusworks
moves through the water?
Go to www.scilinks.com. To find links related
to marine ecosystems, type in the keyword
HL5490. Then, use the links to answer the
following questions about marine ecosystems.
You plan to enter a paper airplane contest sponsored
Flaps
by Talkin’ Physical Science magazine. The person
whose airplane flies the farthest wins a lifetime subscription to the magazine! The week before the contest, you watch an airplane landing at a nearby
airport. You notice that the wings of the airplane have
flaps, as shown in the illustration at right. The paper
airplanes you’ve been testing do not have wing flaps.
What question would you ask yourself based on these observations? Write your
question in the space below for “State the problem.” Then tell how you could use
the other steps in the scientific method to investigate the problem.
CRITICAL THINKING
1. State the problem.
2. Form a hypothesis.
Name
SPECIAL NEEDS
3. What is the largest animal on Earth?
4. Describe an ocean animal.
12
Introduction to Plants
I’ve got this great idea for a new product called the Bliss
Heater. It’s a portable, solar-powered space heater.
The heater’s design includes these features:
• he heater will be as long
T
wide as a acking box.
• he heater
p will have a
T glass top set at an angle
to catch the sun’s rays.
• he inside of the heater
5.T Draw
conclusions.
will be dark
colored to
absorb solar heat.
4. Analyze
the results.
as an adult’s arm and as
GENERAL
SCIENCE PUZZLERS, TWISTERS & TEASERS
1. Each of the statements below represents the fantasy of a member
of one of the main groups of plants. Which of the following types
of plants would have each fantasy—an angiosperm, a gymnosperm, or a horsetail? Each plant type can be used only once.
a. “I’d like to live in a wet, marshy area. Having a job in the
abrasives industry would be suited to my natural gifts.”
Joseph D. Burns
Inventors’ Advisory Consultants
Portland, OR 97201
If you think my idea will work, I will make the Bliss
Heaters right away without wasting time and money on testing and making models. Please write back soon with your
opinion.
b. “I want to be the most successful plant in the kingdom. I’d
also like to be very colorful so all of the animals will find me
attractive.”
GENERAL
c. “I’d love to have a large, extended family with a lot of relatives,
old and young alike, living all over the world. Pollen is important to me, but I can do without fruit.”
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Copyright © by Holt, Rinehart and Winston. All rights reserved.
2. What percentage of the Earth’s water is found in the oceans?
SCIENCE PUZZLERS,
TWISTERS & TEASERS
“Plant”asy Puzzler
Dear Mr. Burns,
15. the methods humans use to take
care of soil:
OSIL VASETONRICON
Topic: Reproductive System
Irregularities
SciLinks code: HL5490
CHAPTER
SAMPLE
A Solar Solution
3. observation
Copyright © by Holt, Rinehart and Winston. All rights reserved.
1. What percentage of the Earth’s surface is
covered by water?
Name _______________________________________________ Date ________________ Class______________
Date
Critical Thinking
_______________________ 8. how chlorine and sodium combine to form table salt
_______________________ 9. why you move to the right when the car you are in
MATTER + AIR ➔ PHYSICAL SCIENCE
turns left
3. What do air, a ball, and a cheetah have in common?
Class
Developed and maintained by the
National Science Teachers Association
GENERAL
3. Test the hypothesis.
2. technology
8. type of weathering caused by
physical means: CLEMANIACH
_______________________ 7. why water boils at 100°C
SAMPLE
Complete this worksheet after you finish reading the Section: [Unique Section
Title]
Skills Worksheet
14. the process in which wind, water,
or ice moves soil from one
VOCABULARY
PRATEN CORK
location to another: ROOSINE
In your own words, write a definition of the following term in the space provided.
Date
SciLinks Activity
MARINE ECOSYSTEMS
13. small particles of decayed plant
and animal material in soil:
MUUSH
Section:
Unique
6. rock that is a source of soil:
Class
Activity
The Plane Truth
SAMPLE
Vocabulary & Notes
5. a mixture of small mineral fragments and organic matter: LISO
. Chemists
SCILINKS ACTIVITY
Name
SAMPLE
Reinforcement
Skills Worksheet
Skills Worksheet
5. Chemistry and physics are both fields of
Date
Skills Worksheet
Activity
Skills Worksheet
Class
Labs and Activities
ECOLABS &
FIELD ACTIVITIES
WHIZ-BANG
DEMONSTRATIONS
LONG-TERM PROJECTS &
RESEARCH IDEAS
DATASHEETS FOR
QUICK
QUICKLABS
LABS
TEACHER RESOURCE PAGE
Name
Date
DEMO
Class
3
Name ___________________________________________________ Date _________________ Class _____________
TEACHER-LED DEMONSTRATION
8
E CO L A B
Inner Life of a Leaf
STUDENT WORKSHEET
The Case of the Ravenous Radish
The Industrial Radish Growers Association (IRGA) is mad. It is suing Ma Olson’s
Happy Radish Co-op for libel, slander, and defamation. Recently, Ma Olson ran
an ad claiming that Co-op radishes are bigger, healthier, and tastier than those
grown by the IRGA. The IRGA says there is nothing to support that claim.
Ma Olson, Co-op founder and owner, stands by her claim and says that the ad
is true. The fields of the Co-op are much more spacious than IRGA farms, which
grow “ravenous radishes” due to crowded conditions.
The IRGA is suing Ma Olson for damage to its reputation and to its business. It
is up to you, the jury, to decide if Ma Olson’s claims are true and to close the
Case of the Ravenous Radish.
Purpose
This activity demonstrates how the vascular system of a plant functions and introduces students to plant structures.
Time Required
10–15 minutes
Lab Ratings
EASY
HARD
TEACHER PREP
12
5. Position the bottom of the straw just inside the mouth of the bottle, above the
water. Seal the clay around the straw,
and double-check that the rest of the
bottle opening is still sealed.
6. Ask students to watch the plant carefully
as you inhale air from the bottle. (Be
careful to keep the straw above the water!) Since the clay has created a tight
seal, withdrawing air from the bottle will
be a challenge.
Plant Planet
How does overpopulation affect the growth and
development of radish plants?
Make a Prediction
1. How does overpopulation affect the growth and development of radish plants?
MATERIALS
•
•
•
•
•
•
1. Do some research on making plant-based dyes. Prepare five
plant-based dyes from plants you collected or purchased
from a grocer or greenhouse. Make a display with a picture
of each plant and a sample of the dye color it makes.
SAFETY ALERT!
modeling clay
stem
HELPFUL HINT
Conduct an Experiment
2. Fill the container with potting soil up to 3 cm from the top.
Do not pack the soil. Holes in the soil trap water.
3. Divide the container in half by placing a line down the center of its side with masking tape as shown. Label one side
“crowded” and the other side “uncrowded.” Label the container with the names of your group members.
4. With the eraser end of a pencil, poke two rows of six holes,
1 cm deep, into the soil, as shown. Be sure the holes are
spaced about 3 cm apart and at least 3 cm away from the
sides of the container.
5. On the “crowded” side of the container, place six radish
seeds in each hole. Cover the holes with soil.
What to Do
1. Fill a soda bottle of water to within
3 cm of the top.
2. Cut a leaf from the ivy plant so that
the stem is approximately 8 cm. Wrap a
piece of clay around the stem, near the
leaf.
3. Place the stem into the bottle so that
its end is below the surface of the water. Cover the opening of the bottle
with the clay, making sure that the
bottle is tightly sealed.
Explanation
Holes called stomata perforate the leaf. Tiny
tubes called xylem and phloem run up and
down the stem. The xylem carries water up
from the roots to the stem and leaves just
like the straw carried air to your mouth.
The phloem carries carbohydrates, which are
produced by photosynthesis in the leaves
If you have trouble
finding a plant in the
field guide, it may be
helpful to find out the
plant’s common name.
4. Where does your food come from? You might get your
food at a supermarket, but most foods in supermarkets
originally come from farms. Research current methods of
growing food in the United States. How big is the average
American farm? What is commonly used for pest control
and fertilizer in the United States? Are there effective alternative methods available? Design an informative brochure
that explains your findings. You may want to compare the
agricultural system of the United States with that of
another country.
Lee Yassinski
Sun Valley Middle School
Sun Valley, California
7. Fill a cup with water, and pour half of the water over the
seeds in each side of the container. Place the container in
the area that your teacher has set aside.
2. Visit a woodland, park, field, or pond, and make detailed
drawings and descriptions of 10 wild plants. Remember to
include the following: size, shape, and coloring of the
plant; leaf size and shape; flower, fruit, or nut size; special
features of the stem or trunk; and the date and location
you found the plant. Use a plant field guide for your area
to identify the 10 plants. Look up each plant’s scientific
name, its common name, how it reproduces, and where
and when it grows. Then find out if the plant is edible to
animals or humans and if the plant has any other uses
(medicinal, dyeing, clothmaking). Make a small field
guide about the 10 plants, including your sketches and
the results of your research.
Research Ideas
continued...
DATASHEETS FOR
CHAPTER LABS
Analysis
1. Determine about how long an action potential lasts.
TEACHER RESOURCE PAGE
Another Long-Term Project Idea
3. Plants were used to treat diseases long before modern medicines were developed. Research the medicinal uses of
plants. What products have been developed from rainforest plants or underwater plants? How effective are medicinal plants compared with more traditional medicines?
Write a news article highlighting your findings.
4. Use a pencil to poke a hole through the
clay to make an opening for the straw.
6. On the “uncrowded” side of the container, place two radish
seeds in each hole. Cover the holes with soil.
GENERAL
Avoid poison oak, poison ivy, and poison
sumac. Also avoid
allergen-producing
plants, such as ragweed, and plants
containing thorns.
SAMPLE
The graph below illustrates changes that occur in the membrane potential of a
neuron during an action potential. Use the graph to answer the following
questions. Refer to Figure 3 as needed.
To Dye For
leaf
straw
soda bottle
tap water
ivy plant
modeling clay about the size of a walnut
plastic drinking straw
scissors
Date
DATASHEET FOR QUICK LAB
Background
Did you know that you can eat dandelions?
It’s true—fresh dandelion leaves make a
tasty salad, and the roots can be boiled to
make tea. In fact, many of the plants we
think of as weeds can be used in dyes,
foods, or medicines.
CLEAN UP
Ask a Question
MATERIALS
Class
Reaction to Stress
STUDENT WORKSHEET
CONCEPT LEVEL
• disposable gloves
• plastic rectangular
containers
• potting soil
• masking tape
• metric ruler
• pencil
• 48 radish seeds
• permanent marker
• large plastic cup
• water
• spray bottle
Name
Quick Lab
PROJECT
Skills Practice Lab
DATASHEET FOR CHAPTER LAB
Using Scientific Methods
SAMPLE
Teacher’s Notes
TIME REQUIRED
One 45-minute class period.
RATING
Teacher Prep–3
Student Set-Up–2
Concept Level–2
Clean Up–2
Easy
1
2
3
4
Jason Marsh
Montevideo High
and Country School
Hard
DATASHEETS FOR
LABBOOK
MATERIALS
The materials listed on the student page are enough for a group of 4–5 students.
Large, dried beans of any kind will work well in this exercise.
TEACHER RESOURCE PAGE
SAFETY CAUTION
Skills Practice Lab
DATASHEET FOR LABBOOK LAB
Remind students to review all safety cautions and icons before beginning this lab
activity.
Does It All Add Up?
SAMPLE
Teacher’s Notes
TIME REQUIRED
One 45-minute class period.
Jason Marsh
Montevideo High
Review and Assessments
SECTION QUIZ
Name
Class
Date
Assessment
Section: Energ
______ 1. building molecules that can be used as
an energy source. or breaking down molecules
in which energy is stored
GENERAL
c. heterotroph
d. cellular respiration
______ 3. an organism that uses sunlight or inorganic
substances to make organic compounds
f. cellular respiration
e. metabolism
SECTION REVIEW
______ 5. an organism that consumes food to get energy
______ 6. the process of getting energy from food
logs burning in a fire
SAMPLE
cells, such as sperm or egg
cells, are called?
a. genes
b. chromosomes
c. gamates.
d. zygotes.
______10. Which of the following most
closely resembles cellular
respiration?
a. warm water moving
______ 8. An organism’s reproductive
2. How does a trace fossil differ from petrified wood?
cells, such as sperm or egg
through copper pipes
cells, are called?
b. people movimg alomg a
escalator
a. genes
b. chromosomes
c. mixing different foods in
c. gamates.
a blender
3. Define fossil.
d. zygotes.
d.
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Name
Class
Date
1. Define biome in your own words.
______ 1. Surface currents are formed by
a. the moon’s gravity.
b. the sun’s gravity.
Name
c. wind.
d. increased water density.
______ 2. When waves come near the shore,
a. they speed up.
c. their wavelength increases.
b. they maintain their speed.
d. their wave height increases.
CHAPTER TEST A
Class
Date
Assessment
Chapter Test A
SAMPLE
5. Use each of the following terms in an original sentence: plankton, littoral
zone, and estuary.
[Unique
MULTIPLE CHOICE
In the space provided, write the letter of the term or phrase that best completes
each statement or best answers each question.
______ 1. Surface currents are formed by
6. Describe how marshes and swamps differ.
a. the moon’s gravity.
c. wind.
b. the sun’s gravity.
d. increased water density.
______ 2. When waves come near the shore,
a. they speed up.
c. their wavelength increases.
b. they maintain their speed.
d. their wave height increases.
GENERAL
______ 3. Longshore currents transport sediment
c. only during low tide.
a . out to the open ocean.
b. along the shore.
d. only during high tide.
______ 4. Which of the following does NOT control surface currents?
a global wind
c Coriolis effect
Copyright © by Holt, Rinehart and Winston. All rights reserved.
______ 3. Longshore currents transport sediment
a . out to the open ocean.
c. only during low tide.
b. along the shore.
d. only during high tide.
CHAPTER TEST C
______ 4. Which of the following does NOT control surface currents?
a. global wind
c. Coriolis effect
b. tides
d. continental deflections
______ 5. Whitecaps break
Name
Standardized Test Preparation
Date
SAMPLE
READING
In the space provided, write the letter of the term or phrase that best completes
each statement or best answers each question.
GENERAL
Class
Assessment
MULTIPLE CHOICE
2. Describe the characteristics of a savanna and a desert.
STANDARDIZED TEST
PREPARATION
Name
SAMPLE
Chapter Test B
[Unique
4. Compare the open-water zone and the deep-water zone.
In
the space provided, write the letter of Class
the term or phrase thatDate
best completes
Name
each statement or best answers each question.
Skills Worksheet
______ 7. Which of the following most
______ 9. An organism’s reproductive
CHAPTER TEST B
Assessment
SAMPLE
3. Identify the relationship between tundra and permafrost.
______ 4. an organism that uses sunlight or inorganic
substances to make organic compounds
UNDERSTANDING KEY IDEAS
Date
a. photosynthesis
b. autotroph
______ 2. the process by which light energy is converted
to chemical energy
GENERAL
Class
Chapter Review
USING VOCABULARY
In the space provided, write the letter of the description that best matches the
term or phrase.
respiration?
a. warm water moving
through copper pipes
Section: Unique
b. people movimg alomg a
KEY TERMS
escalator
1. What do paleontologist study?
c. mixing different foods in
a blender
d. logs burning in a fire
Name
Skills Worksheet
SAMPLE
Section Quiz
Section
Review
closely
resembles cellular
CHAPTER REVIEW
Class
a. in the surf.
Assessment
b. in the breaker zone.
Chapter Test C
Date
Passage 1 adventurous summer camp in the world. Billy can’t
wait to head for the outdoors. Billy checked the recommended
supply list: light, summer clothes; sunscreen; rain gear; heavy,
down-filled jacket; ski mask; and thick gloves. Wait a minute! Billy
thought he was traveling to only one destination, so why does he
need to bring such a wide variety of clothes? On further investigation, Billy learns that the brochure advertises the opportunity to
“climb the biomes of the world in just three days.” The destination
is Africa’s tallest mountain, Kilimanjaro.
PERFORMANCE-BASED
ASSESSMENT
______ 1. The word destination in this passage means
A camp
B vacation.
C place.
D mountain.
______ 2. Which of the following is a FACT in the passage?
F People ski on Kilimanjaro.
G Kilimanjaro is Africa’s tallest mountain.
H It rains a lot on Kilimanjaro.
Class
Date
J The summers are cold on Kilimanjaro.
Assessment
SKILL BUILDER
______ 3. Billy wondered if the camp was advertising only one destination after
SAMPLE
he read the brochure, which said that
A the camp was the most adventurous summer camp in the world.
B he would need light, summer clothes and sunscreen.
OBJECTIVE C he would need light, summer clothes and a heavy, down-filled
jacket.
Determine which
factors cause some sugar shapes to break down faster than others.
D the summers are cold on Kilimanjaro.
KNOW THE SCORE!
As you work through the activity, keep in mind that you will be earning a grade
for the following:
Name
c. in the open ocean.
d. as their wavelength increases.
SAMPLE
______ 6. Most ocean waves are formed by
a . earthquakes.
c. landsides.
b. wind.
d. impacts by cosmic bodies.
[Unique
______ 7. Which factor controls surface currents?
MULTIPLE CHOICE
a. global winds
c. continental deflection
In the space
write
the letter of the term
or phrase
that best completes
b.provided,
the Coriolis
effect
d. all
of the above
each statement or best answers each question.
______ 8. Streamlike movments of ocean water far below the surface are
______ 1. called
Surface currents are formed by
a. jet
thecurrents
moon’s gravity.
c. surface
wind. currents.
a.
c.
b. Coriolis
the sun’scurrents.
gravity.
d. deep
increased
water density.
b.
d.
currents.
2. When
When the
waves
come
near
the moon
shore, that can be seen from Earth
______ 9.
sunlit
part
of the
______
a. theylarger,
speed it
up.is
c. their wavelength increases.
grows
b.
they maintain their speed.
d.
their
height phase.
increases.
a. waxing.
c. in
thewave
new moon
b. waning.
d. in the full moon phase.
______ 3. Longshore currents transport sediment
. out
to theWay
open
Milky
is ocean.
thought to be c. only during low tide.
______10. aThe
b.
along
the shore.
d.
only
during
high tide.
a. an
elliptical
galaxy.
c. a
spiral
galaxy.
SPECIAL NEEDS
______ 4. Which of the following does NOT control surface currents?
a global wind
c Coriolis effect
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Read the passages below. Then, read each question that follows the passage.
Decide which is the best answer to each question.
GENERAL
Performanced-Based Assessment
• how you form and test the hypothesis (30%)
• the quality of your analysis (40%)
• the clarity of your conclusions (30%)
Using Scientific Methods
GENERAL
ASK A QUESTIONS
Why do some sugar shapes erode more rapidly than others?
MATERIALS AND EQUIPMENT
© by Holt,
Rinehart
1 regular
sugar
cubeand Winston. All rights reserved.
•Copyright
• 90 mL of water
Chapter 12 • Chapter Resources 297D
12
Chapter Enrichment
This Chapter Enrichment provides relevant and
interesting information to expand and enhance
your presentation of the chapter material.
Seedless Plants
Bryophytes
•
What Is a Plant?
Theophrastus
•
Theophrastus (c. 372–287 BCE) was Aristotle’s student
and one of the first botanists. He wrote two books
about plants, Inquiry into Plants and Growth of Plants.
He described the morphology, uses, propagation, and
pollination of 500 plants and described sexual reproduction in plants. Theophrastus directed the Lyceum,
a school and center of learning in Athens. The Lyceum
housed the first botanical garden. Theophrastus’s writings were the standard for botanical study until the
16th century.
Bryophytes, which include mosses, hornworts, and
liverworts, make up more than 15,000 described species worldwide. Various species tend to be restricted to
particular environments because of sensitivities to
temperature, light, water availability, and chemical
composition of the substrate. So, bryophytes are good
indicator species for ecologists and conservation biologists. These experts can characterize an environment
by identifying the bryophytes present in an area.
Is That a Fact!
◆ Before the invention of flashbulbs and strobe lights
for indoor and low-light photography, photographers
created an explosive flash of light with a powder. The
powder contained spores from club mosses, seedless
vascular plants that are related to ferns and horsetails.
•
Bryophytes are small and are easy to culture in the lab.
Field biologists, however, usually observe bryophytes
year-round under natural conditions.
Carnivorous Plants
•
Carnivorous plants photosynthesize and are true
plants. They often grow in wetlands, such as marshes,
where soil is waterlogged. Bacteria and fungi cannot
thrive in these soils, so little organic matter is decomposed to provide minerals to plants. The small invertebrates that carnivorous plants catch provide additional
minerals, especially nitrogen. The insects are digested
by enzymes secreted by the leaves or by bacteria and
fungi living in the cupped leaves of the plant.
Is That a Fact!
◆ The leaves of a pitcher plant form tall, narrow cups
that hold rainwater. The tip of the plant is colorful
and has nectar-secreting glands that attract insects.
The insects follow a path of tiny hairs down into the
cup, where the walls are smooth. The insects lose
their grip and drown.
297E Chapter 12 • Introduction to Plants
Evolution of Ferns
•
Ferns are an ancient group of plants with fossil records
dating to the middle of the Devonian period, 408 to
345 million years ago. Nearly all of those early fern
groups are now extinct. Few modern fern genera can
be traced directly to their Carboniferous ancestors.
For background information about teaching strategies and
issues, refer to the Professional Reference for Teachers.
Seed Plants
Structures of Seed Plants
The Millennium Seed Bank
Inflorescences
•
•
The Royal Botanic Gardens in Kew, England, has
launched a project to collect seeds from 24,000 plant
species around the world. As many as 50,000 species of
plants might become extinct in the next 30 years, but
the seed bank will ensure the survival of plants that
help stabilize soil and provide food, medicine, and
building materials. The collected seeds are dried and
stored in subzero temperatures. Scientists believe the
seeds will grow even hundreds of years in the future.
The Economic Importance of Plants
•
Farming originated thousands of years ago. Today,
three of the earliest cultivated crops—wheat, rice, and
corn—feed more than half of the people in the world.
•
Herbs and spices were valued commodities on ancient
trade routes. In medieval times, explorers and merchants brought spices to Europe by camel caravan
from east Asia.
•
Perfume makers use essential oils from a variety of
flowers, including rose, orange, lavender, and jasmine.
•
The ancient Egyptians made paper from papyrus reeds.
Paper can also be made from nettles, bamboo, cotton,
hemp, and other plants. Today, most paper is made
from wood pulp.
Is That a Fact!
◆ The sea bean (genus Mucuna) is one of the largest seed
pods in the world. When a sea bean pod falls into a
river, it floats to the ocean, where it may travel for
thousands of miles before it is washed onto shore.
The cluster of flowers that
develops on many plants
is called an inflorescence,
of which there are two
types. In a determinate
inflorescence, the peduncle, or main axis, terminates in a flower bud, which
prevents the peduncle
from continued growth.
In indeterminate inflorescences, the lower buds
open first. As the peduncle
continues to grow, the
youngest flowers are always
at the top. There are several forms of inflorescences,
including the following:
• raceme: each flower of the cluster is on a pedicel,
or short stem, that extends from the peduncle
(snapdragon)
• spike: resembles a raceme but has no pedicels
(gladiolus)
• panicle: branched raceme in which each branch
has multiple flowers (lilac)
• head: short, dense spike with flowers in a circular
mass (dandelion)
• umbel: all the pedicels grow from the same point
at the top of the peduncle (onion)
Developed and maintained by the
National Science Teachers Association
SciLinks is maintained by the National Science Teachers Association
to provide you and your students with interesting, up-to-date links that
will enrich your classroom presentation of the chapter.
Visit www.scilinks.org and enter the SciLinks code for more
information about the topic listed.
Topic: Plant Characteristics
SciLinks code: HSM1158
Topic: Plants with Seeds
SciLinks code: HSM1168
Topic: How Are Plants Classified?
SciLinks code: HSM0763
Topic: Structure of Seed Plants
SciLinks Code: HSM1467
Topic: Seedless Plants
SciLinks code: HSM1368
Chapter 12 • Chapter Enrichment 297F
12
12
Overview
Tell students that this chapter
will help them learn about
plants. The chapter describes
the four basic groups of plants.
The chapter also discusses the
structures of flowering plants.
Assessing Prior
Knowledge
Introduction
to Plants
Students should be familiar
with the following topics:
Plants have several common
characteristics and can be
classified by their structures.
• cells
• photosynthesis
SECTION
Identifying
Misconceptions
1 What Is a Plant? . . . . . . . . . . . . 300
As students learn the material in
this chapter, some of them may
think that plants get all of their
food from soil. Plants do get
water and some water-soluble
minerals from soil, but the mass
of plants—even large plants,
such as trees—is derived from
the carbon dioxide gas that
plants take in from the air for
photosynthesis. This carbon
dioxide is combined with water
to make larger molecules, such
as glucose. In turn, glucose is
used to make storage molecules,
such as sucrose and starch.
2 Seedless Plants . . . . . . . . . . . . 304
3 Seed Plants. . . . . . . . . . . . . . . . 308
4 Structures of Seed Plants . . . . 314
About the
Standards Correlations
National Science Education Standards
The following codes indicate the National Science Education
Standards that correlate to this chapter. The full text of the
standards is at the front of the book.
Chapter Opener
Section 3 Seed Plants
UCP 1, 2, 4; SAI 1; SPSP 4; LS 1a, 1d, 2b, 2c, 2d, 4b, 4c, 4d, 5b;
LabBook: UCP 2, 5; SAI 1, 2; LS 2b
Section 4 Structures of Seed Plants
UCP 1, 2, 4; SAI 1; SPSP 5; LS 1a, 1d, 2b, 3d, 4c, 5b;
LabBook: UCP 1, 5; SAI 1
SAI 1, 2; LS 1c, 3a
Chapter Lab
Section 1 What Is a Plant?
UCP 1, 2, 5; SAI 1, 2; ST 2; HNS 1, 2; LS 1a, 2a, 2b
UCP 1, 2, 4; SAI 1, 2; ST 2; HNS 2; LS 1a, 2b, 4c, 5a
Chapter Review
Section 2 Seedless Plants
UCP 1, 2, 3, 4; SAI 1; ST 2; SPSP 4, 5; HNS 2; LS 1a, 1c, 1d, 2b,
2c, 2d, 3d, 4b, 4c, 4d, 5a, 5b, 5c
UCP 1, 2, 3, 4; SAI 1; LS 1a, 1c, 2b, 5c
298
Pyramid Before you
read the chapter, create the
FoldNote entitled “Pyramid”
described in the Study Skills section
of the Appendix. Label the sides of
the pyramid with “Nonvascular plants,”
“Seedless vascular plants,” and “Seed
plants.” As you read the chapter, define
each kind of plant, and write characteristics of each kind of
plant on the appropriate pyramid side.
In Costa Rica’s Monteverde Cloud Forest
Preserve, a green coil begins to unfold. It is
hidden from all but the most careful observer.
The coil looks alien, but it is very much of this
Earth. The coil is the leaf of a fern, a plant
that grows in moist areas. Soon, the coil will
unfold into a lacy, delicate frond.
Chapter 12 • Introduction to Plants
START-UP
v
MATERIAL S
FOR EACH GROUP
• aluminum foil
• bean seeds (3–4)
• bottle, soda, clear plastic, with
neck cut off, 2 L
• potting soil, moist
• water, 60 mL
Safety Caution: Some
students—particularly those
who suffer from allergies—may
wish to wear protective gloves
while handling the soil and
seeds. Have students wash their
hands when they are finished
with the activity.
Teacher’s Notes: Cut off the
neck of each bottle before distributing bottles to students.
Soaking the seeds overnight in
advance will decrease the number of days until germination.
Answers
START-UP
Observing Plant Growth
When planting a garden, you bury seeds and water
them. What happens to the seeds below the soil?
How do seeds grow into plants?
Procedure
4. Water the seeds with about 60 mL of water, or
water them until the soil is moist. Add more water
when the soil dries out.
5. Place the bottle in an area that receives sunshine.
Check on your seeds each day, and record your
observations.
1. Fill a clear 2 L soda bottle to within 8 cm of the
top with moist potting soil. Your teacher will have
already cut off the neck of the bottle.
Analysis
2. Press three or four bean seeds into the soil and
against the wall of the bottle. Add enough additional potting soil to increase the depth by 5 cm.
2. How long did the seeds take to start growing?
1. Answers may vary. Students
may report that not all of their
seeds grew.
2. Answers may vary. Germination
times vary depending on the
seeds used.
3. Sample answer: The seed
contains stored food that is
used for energy to grow.
1. How many seeds grew?
3. From where did the seeds most likely get the
energy to grow?
3. Cover the sides of the bottle with aluminum foil
to keep out light. Leave the top of the bottle
uncovered.
Introduction to Plants
CHAPTER STARTER
Science in Action
CHAPTER RESOURCES
Technology
ST 2; SPSP 1, 3, 4, 5; HNS 1, 2, 3; LS 1f
Transparencies
READING
• Chapter Starter Transparency
SKILLS
Student Edition on CD-ROM
Guided Reading Audio CD
• English or Spanish
This Really Happened!
A lone scientist trudges through a remote
rain forest. Peering into a steep, narrow
canyon, he notices something unusual.
On closer inspection, he discovers that
it is a species of tree that has survived
from the days when Tyrannosaurus rex
and Velociraptor walked the Earth!
No, this isn’t a scene out of Jurassic
Park. This really happened in an Australian
rain forest in 1994. The scientist’s name
was David Noble. He discovered a tree
species that dates back to the Cretaceous
period, between 144 million and 65
million years ago.
The trees, called Wollemi pines, have
large, bladelike leaves and knobby brown
bark. They grow as tall as 35 m, and their
trunks can grow as wide as 1 m.
Since the discovery of the trees,
scientists at the Royal Botanic Gardens
in Sydney, Australia, have been planting
seeds of the Wollemi pines and growing
seedlings. Soon Wollemi pines will be
made available to gardeners so they can
transform their yards into their own
Cretaceous parks.
In this chapter, you will learn more
about the mysterious world of plants.
You will see that plants are complex
organisms that challenge our understanding of nature.
Chapter Starter Transparency
Use this transparency to help students
begin thinking about the world of
plants.
Classroom Videos
• Brain Food Video Quiz
Workbooks
Science Puzzlers, Twisters & Teasers
• Introduction to Plants g
Copyright © by Holt, Rinehart and Winston. All rights reserved.
Chapter 12 • Introduction to Plants 299
1
1
Overview
In this section, students will
learn the shared characteristics
of plants. Plants make their
own food, have a cuticle, reproduce with spores and sex cells,
and have cells with cell walls.
Finally, students will learn about
the four main groups of plants.
What You Will Learn
Identify four characteristics that all
plants share.
Describe the four main groups of
plants.
Explain the origin of plants.
Vocabulary
nonvascular plant
vascular plant
gymnosperm
angiosperm
Bellringer
Tell students that there are four
major types of plants. Ask them
to try to identify those types
and to give at least two examples for each one. (Students likely
will not classify plants according to
the section information. Students
may name flowers, trees, weeds,
grasses, fruits, and vegetables.)
READING STRATEGY
Reading Organizer As you read
this section, create an outline of the
section. Use the headings from the
section in your outline.
What Is a Plant?
Imagine spending a day without plants. What would you eat?
It would be impossible to make chocolate chip cookies and
many other foods.
Without plants, you couldn’t eat much. Almost all food is
made from plants or from animals that eat plants. Life would
be very different without plants!
Plant Characteristics
Plants come in many different shapes and sizes. So, what do
cactuses, water lilies, ferns, and all other plants have in common? One plant may seem very different from another. But
most plants share certain characteristics.
Photosynthesis
Take a look at Figure 1. Do you know why this plant is green?
Plant cells contain chlorophyll (KLAWR uh FIL). Chlorophyll
is a green pigment that captures energy from sunlight.
Chlorophyll is found in chloroplasts (KLAWR uh PLASTS). Chloroplasts are organelles found in many plant cells and some
protists. Plants use energy from sunlight to make food from
carbon dioxide and water. This process is called photosynthesis
(FOHT oh SIN thuh sis). Because plants make their own food,
they are called producers.
Cuticles
l Verbal
Most plants live on dry land and need sunlight to live. But why don’t plants dry out?
Plants are protected by a cuticle. A cuticle is
a waxy layer that coats most of the surfaces
of plants that are exposed to air. The cuticle
keeps plants from drying out.
Demonstration -------------g
Water Travel in Plants Slice a
stalk of celery lengthwise to just
below the leaves. Place the two
halves in separate beakers, each
containing a different color of
water. Red and blue food colorings work best. Students should
be able to see the veins in the
leaves change color after the
colored liquids have traveled
up the stalk.
l Visual
Figure 1 Chlorophyll makes
the leaves of this plant green.
Chlorophyll helps plants make
their own food by capturing
energy from sunlight.
e
CHAPTER RESOURCES
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CRF
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• Directed Reading B s
Technology
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Interactive Textbook Struggling Readers
300
Chapter 12 • Introduction to Plants
Cultural
Awareness
g
Breadnut Ancient Maya and Aztec
people made extensive use of the fruit
of the breadnut tree. It was boiled and
eaten like potatoes or mashed into a
gruel and sweetened. Breadnuts were
ground, cooked, and mixed with corn
to make tortillas. Diluted breadnut sap
was fed to babies when their mother’s
milk was not available. Breadnut leaves
were also fed to female animals to
increase their milk supply.
Figure 2
Some Structures of a Photosynthetic Plant Cell
Group
A vacuole stores water,
helps support the cell,
and plays a role in many
other cell functions.
Chloroplasts contain
chlorophyll. Chlorophyll
captures energy from
the sun. Plants use this
energy to make food.
The cell membrane
surrounds a plant cell
and lies beneath the
cell wall.
MATERIAL S
FOR EACH GROUP
• baby powder
• eyedropper or spoon
• water
Baby-Powder Cuticle Have students work in groups of four.
Give each group one set of the
materials listed above. Tell students that all but one member
of the group should coat the
palms of their hands with baby
powder. Instruct the remaining
member of the group to release
a few drops of water on his or
her classmates’ hands and to
record his or her observations.
Explain to students that a plant’s
cuticle forms a similar barrier to
keep the plant from losing moisture. Students should wash their
hands immediately following
this exercise.
The cell wall surrounds
the cell membrane. The
cell wall supports and
protects the plant cell.
Cell Walls
How do plants stay upright? They do not have skeletons like
many animals do. Instead, plant cells are surrounded by a
rigid cell wall. The cell wall lies outside the cell membrane,
as shown in Figure 2. Carbohydrates and proteins in the cell
wall form a hard material. Cell walls support and protect the
plant cell. Some plant cells also have a secondary cell wall that
forms after the cell is mature. When this wall has formed, a
plant cell cannot grow larger.
Reproduction
Plants have two stages in their life cycle—the sporophyte
(SPAWR uh FIET) stage and the gametophyte (guh MEET uh FIET)
stage. In the sporophyte stage, plants make spores. In a suitable
environment, such as damp soil, the spores of some plants
grow. These new plants are called gametophytes.
During the gametophyte stage, female gametophytes produce eggs. Male gametophytes produce sperm. Eggs and sperm
are sex cells. Sex cells cannot grow directly into new plants.
Instead, a sperm must fertilize an egg. The fertilized egg grows
into a sporophyte. The sporophyte makes more spores. So, the
cycle starts again.
v -------g
Countries and Crops Without plants, most life on land
couldn’t survive. But plants
are important for more than
the survival of living things.
Many countries rely on plants
for income. Identify five major
food crops. Then, find out
which countries are the main
producers of these crops and
how much the countries produce each year. Make a table
to show your findings.
l Kinesthetic
e
v--------------------------------------a
Life Cycles Have
students compare and
contrast the basic life cycle of a
plant with the basic life cycles of
bacteria and fungi. Ask students
to create a series of illustrations
that show how all three types of
organisms reproduce and to
include captions that explain
similarities and differences.
PORTFOLIO
✓
Reading Check How do plants reproduce? (See the Appendix for
answers to Reading Checks.)
l Visual/Verbal
SUPPORT FOR
English Language Learners
Reproductive Cycle Having students
write summaries can improve their
comprehension of text material. After
students finish reading about plant
reproduction, ask them to summarize
the reproductive cycle of plants in their
own words in their science journals.
Evaluate the summaries for completeness and accuracy of information, as
well as appropriate use of language and
new terms. l Verbal
Answer to Connection to Social Studies
Answer to Reading Check
Students will likely research crops such as
rice, wheat, corn, and soybeans. Students may
also study other crops, such as bananas, cacao,
and coffee. Students should demonstrate an
understanding of where these crops are produced and how much of the crop is produced
each year.
In the sporophyte stage, plants
make spores, which grow into
gametophytes. The gametophytes
produce eggs and sperm. A sperm
fertilizes an egg. The fertilized egg
grows into a sporophyte.
Section 1 • What Is a Plant? 301
Plant Classification
Although all plants share basic characteristics, they can be classified into four groups. First, they are classified as nonvascular
plants and vascular plants. Vascular plants are further divided
into three groups—seedless plants, nonflowering seed plants,
and flowering seed plants.
Reteaching -------------------------------------b
Plant Groups Ask students
to list the four main groups of
plants and to give an example
of a plant from each group. Be
sure that students understand
the characteristics of each plant
group. l Logical
Quiz ---------------------------------------------------------------------g
1. How is a plant’s size related
to its method of transporting
water and nutrients? (Sample
answer: Nonvascular plants rely
on diffusion, which is efficient
only in small plants. Vascular
plants have conducting tissues,
which enable the plant to be very
large.)
Nonvascular Plants
nonvascular plant the three
groups of plants (liverworts, hornworts, and mosses) that lack specialized conducting tissues and true
roots, stems, and leaves
vascular plant a plant that has
specialized tissues that conduct
materials from one part of the plant
to another
gymnosperm a woody, vascular
seed plant whose seeds are not
enclosed by an ovary or fruit
angiosperm a flowering plant that
produces seeds within a fruit
2. What is required for a spore to
grow into a new plant? (It must
land in a suitable environment,
such as damp soil.)
Mosses, liverworts, and hornworts are nonvascular plants. A
nonvascular plant is a plant that doesn’t have specialized tissues
to move water and nutrients through the plant. Nonvascular
plants depend on diffusion to move materials from one part of
the plant to another. Diffusion is possible because nonvascular
plants are small. If nonvascular plants were large, the cells of
the plants would not get enough water and nutrients.
Vascular Plants
In the same way that the human body has special tissues to
move materials through the body, so do many plants. A plant
that has tissues to deliver water and nutrients from one part of
the plant to another is called a vascular plant. These tissues are
called vascular tissues. Vascular tissues can move water to any
part of a plant. So, vascular plants can be almost any size.
Vascular plants are divided into three groups—seedless
plants and two types of seed plants. Seedless vascular plants
include ferns, horsetails, and club mosses. Nonflowering seed
plants are called gymnosperms (JIM noh SPUHRMZ). Flowering
seed plants are called angiosperms (AN jee oh SPUHRMZ). The
four main groups of plants are shown in Figure 3.
✓Reading Check
Alternative
Assessment ---------------------------a
Figure 3
Interview Have students interview one another about the
characteristics common to all
plants. Have students ask, “How
do plants make their own food?”
“Why are cell walls necessary?”
“What is the purpose of the cuticle?” “What are gametophytes
and sporophytes, and what roles
do they play in a plant’s life
cycle?” l Verbal/Interpersonal
The Main Groups of Plants
Nonvascular plants
Mosses, liverworts,
and hornworts
Answer to Reading Check
nonvascular plants, seedless vascular plants,
gymnosperms, and angiosperms
302
Chapter 12 • Introduction to Plants
What are the four main groups of plants?
Vascular plants
Seedless plants
Ferns, horsetails,
and club mosses
Seed plants
Nonflowering
Flowering
Gymnosperms
Angiosperms
Answers to Section Review
The Origin of Plants
Imagine that you traveled back in time about 440
million years. The Earth seems like a strange, bare,
and unfriendly place. For one thing, no plants live
on land. So, where did plants come from?
Take a look at Figure 4. The photo on the left
shows a green alga. The photo on the right shows
a fern. The green alga may look like a plant, such
as a fern, but it isn’t a plant. However, green algae
and plants have many similarities. Green algae cells
and plant cells have the same kind of chlorophyll.
They have similar cell walls. Green algae and plants
make their own food through photosynthesis. Both
store energy in the form of starch. Like plants, green
algae have a two-stage life cycle. Because of these
similarities, some scientists think that green algae
and plants share a common ancestor.
✓
Reading Check What are some characteristics that
green algae and plants have in common?
Review
Figure 4 The similarities between a modern
green alga (left) and plants, such as ferns
(right), suggest that both may have originated
from an ancient species of green algae.
Using Key Terms
Critical Thinking
For each pair of terms, explain how
the meanings of the terms differ.
1. nonvascular plants and vascular
plants
Summary
All plants make their
• own
food and have
•
•
cuticles, cells walls, and
a two-stage life cycle.
Plants are first classified
into two groups: nonvascular plants and vascular
plants. Vascular plants
are further divided into
seedless plants, gymnosperms, and angiosperms.
Similarities between
green algae and plants
suggest they may have a
common ancestor.
2. gymnosperms and angiosperms
Understanding Key Ideas
3. Which of the following plants is
nonvascular?
a. ferns
c. gymnosperms
b. mosses
d. club mosses
8. Making Inferences One difference between green algae and
plants is that green algae do not
have a cuticle. Why don’t green
algae have a cuticle?
9. Applying Concepts Imagine
an environment that is very dry
and receives a lot of sunlight.
Water is found deep below the
soil. Which of the four groups of
plants could survive in this environment? Explain your answer.
4. What are four characteristics that
all plants share?
5. What do green algae and plants
have in common?
6. Describe the plant life cycle.
For a variety of links related to this
chapter, go to www.scilinks.org
Math Skills
7. A plant produced 200,000 spores
and one-third as many eggs.
How many eggs did the plant
produce?
Answer to Reading Check
Sample answer: Green algae and plant cells
have the same kind of chlorophyll, have similar
cell walls, and make their own food through
photosynthesis. Both store energy in the form
of starch and have a two-stage life cycle.
Developed and maintained by the
National Science Teachers Association
Topic: Plant Characteristics;
How Are Plants Classified?
SciLinks code: HSM1158; HSM0763
1. Sample answer: Vascular plants
have tissues to move water and
nutrients, but nonvascular plants
don’t have these tissues.
2. Sample answer: Angiosperms
have flowers, but gymnosperms
don’t have flowers.
3. b
4. Sample answer: Plants make
their own food, have a cuticle,
have cells with cell walls, and
have a two-stage life cycle.
5. Sample answer: Plants and
green algae both have the same
kind of chlorophyll, have a twostage life cycle, store energy in
the form of starch, and have
cells with cell walls.
6. Sample answer: Plants make
spores in the sporophyte stage.
The spores grow into gametophytes. Female gametophytes
produce eggs, and male gametophytes produce sperm, which
fertilize the eggs. A fertilized egg
grows into a sporophyte.
7. 66,667 eggs (200,000 ⫻ 1/3 ⫽
66,667 eggs)
8. Sample answer: A cuticle protects plants from water loss.
But algae live in water, so algae
likely do not experience water
loss. So, algae can survive without cuticles.
9. Sample answer: Vascular plants
can live in a dry environment
because they have tissues for
transporting water and nutrients.
However, seedless vascular
plants need moisture, so only
gymnosperms and angiosperms
could live in the environment.
CHAPTER RESOURCES
Chapter Resource File
CRF
• Section Quiz g
• Section Review g
• Vocabulary and Section Summary g
• SciLinks Activity g
Technology
Transparencies
• L40 The Main Groups of Plants
Interactive Explorations CD-ROM
• Shut Your Trap! g
Section 1 • What Is a Plant? 303
2
Seedless Plants
2
When you think of plants, you probably think of plants, such
as trees and flowers, that make seeds. But two groups of
plants don’t make seeds.
Overview
In this section, students will
learn that seedless plants include
nonvascular plants (mosses, liverworts, and hornworts) and vascular plants (ferns, horsetails,
and club mosses). Finally, students will learn about the
importance of these plants
to the environment and to
humans.
One group of seedless plants is the nonvascular plants—mosses,
liverworts, and hornworts. The other group is seedless vascular
plants—ferns, horsetails, and club mosses.
What You Will Learn
List three nonvascular plants and
three seedless vascular plants.
Explain how seedless plants are
important to the environment.
Describe the relationship between
seedless vascular plants and coal.
Nonvascular Plants
Mosses, liverworts, and hornworts are small. They grow on soil,
the bark of trees, and rocks. These plants don’t have vascular
tissue. So, nonvascular plants usually live in places that are
damp. Each cell of the plant must get water from the environment or from a nearby cell.
Mosses, liverworts, and hornworts don’t have true stems,
roots, or leaves. They do, however, have structures that carry
out the activities of stems, roots, and leaves.
Vocabulary
rhizoid
rhizome
READING STRATEGY
Bellringer
Paired Summarizing Read this section silently. In pairs, take turns summarizing the material. Stop to discuss
ideas that seem confusing.
Ask students the following question: “If plants can make their
own food, why do people add
fertilizer to the soil?” (Sample
answer: Fertilizers add minerals to
the soil that plants cannot make for
themselves.)
Mosses
Mosses often live together in large groups. They cover soil or
rocks with a mat of tiny green plants. Mosses have leafy stalks
and rhizoids (RIE ZOYDZ). A rhizoid is a rootlike structure that
holds nonvascular plants in place. Rhizoids help the plants get
water and nutrients. As you can see in Figure 1, mosses have
two stages in their life cycle.
rhizoid a rootlike structure in nonvascular plants that holds the plants
in place and helps plants get water
and nutrients
Figure 1
Moss Life Cycle
Gametophyte
b The sporophyte
releases spores
into the air.
v--------------------------g
Identifying Plant Parts Before
students read this section, let
them view a moss and a fern.
Ask students to compare the two
plants. (Sample answer: The moss
is much smaller than the fern.) Ask
students to identify the sporophyte and gametophyte. (Help
students recognize these structures.
Depending on the stage of the plant,
the sporophyte or gametophyte may
not be visible.) l Visual
Sporophyte
Male
Female
Gametophyte
a The fertilized
egg grows into
a sporophyte.
Egg
Fertilized egg
Sporophyte
CHAPTER RESOURCES
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CRF
• Lesson Plan
• Directed Reading A b
• Directed Reading B s
Technology
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Interactive Textbook Struggling Readers
304
c Spores land in a
moist place, crack
open, and grow into
leafy gametophytes.
Spores
Chapter 12 • Introduction to Plants
Sperm
d Sperm swim
through water from
the male gametophyte to fertilize the
egg at the top of
the female
gametophyte.
CONNECTION to
History --------------------------------------------------a
Elizabeth Knight Britton Elizabeth
Knight Britton was a botanist when
female scientists faced many obstacles. She was the unofficial curator of
mosses at Columbia University in New
York and published 346 scientific papers
between 1881 and 1930. Britton was especially active in the conservation of plants.
Have students identify one of her accomplishments in this area and write a magazine article about their findings. l Verbal
Writing
Liverworts and Hornworts
Like mosses, liverworts and hornworts are small, nonvascular
plants that usually live in damp places. The life cycles of liverworts and hornworts are similar to the life cycle of mosses.
The gametophytes of liverworts can be leafy and mosslike or
broad and flattened. Hornworts also have broad, flattened
gametophytes. Both liverworts and hornworts have rhizoids.
The Importance of Nonvascular Plants
Nonvascular plants have an important role in the environment.
They are usually the first plants to live in a new environment,
such as newly exposed rock. When these nonvascular plants
die, they form a thin layer of soil. New plants can grow in this
soil. More nonvascular plants may grow and hold the soil in
place. This reduces soil erosion. Some animals eat nonvascular
plants. Other animals use these plants for nesting material.
Peat mosses are important to humans. Peat mosses grow in
bogs and other wet places. In some places, dead peat mosses
have built up over time. This peat can be dried and burned
as a fuel. Peat mosses are also used in potting soil.
✓
Reading Check How are nonvascular plants important to the
environment? (See the Appendix for answers to Reading Checks.)
Seedless Vascular Plants
Moss Mass
1. Determine the mass of
a small sample of dry
sphagnum moss.
2. Observe what happens
when you put a small
piece of the moss in
water. Predict what will
happen if you put the
entire sample in water.
3. Place the moss sample in
a large beaker of water
for 10 to 15 minutes.
4. Remove the wet moss
from the beaker, and
determine the mass of
the moss.
5. How much mass did the
moss gain? Compare your
result with your prediction.
6. What could this plant be
used for?
Ancient ferns, horsetails, and club mosses grew very tall. Club
mosses grew to 40 m in ancient forests. Horsetails once grew to
18 m tall. Some ferns grew to 8 m tall. Today, ferns, horsetails,
and club mosses are usually much smaller. But because they
have vascular tissue, they are often larger than nonvascular
plants. Figure 2 shows club mosses and horsetails.
English Language Learners
Sketch the Cycle Students will better
understand the importance of nonvascular plants if they sketch what happens
when nonvascular plants die. Have pairs
of students draw a simple picture showing the benefits to soil, other nonvascular plants, and animals, based on what
they have read in this section. Encourage them to add labels for clarity. Check
the pictures to be sure they represent all
the benefits accurately. Ask students to
make corrections if necessary. l Visual/
Interpersonal
Teacher’s Notes: It may be
helpful to use a dry beaker of
predetermined mass to hold
the wet moss for weighing.
Answers
4. Answers may vary.
5. Answers may vary. Students
will likely underestimate how
much water the moss can
absorb.
6. Sample answer: The moss
could be used to wipe up
spills.
CONNECTION v
Real World -----------------------------------g
Figure 2 Seedless
vascular plants include
club mosses (left) and
horsetails (right).
SUPPORT FOR
MATERIAL S
FOR EACH GROUP
• balance or scale
• sphagnum moss, dry
• water, in large beaker
Sphagnum Moss Sphagnum
moss was used during World
War I as a dressing for wounds.
Its hollow cells enable it to
absorb up to 20 times its own
weight in fluid. Sphagnum moss
was also once used for diapers,
lamp wicks, and bedding. Have
students research how sphagnum moss is used today. (Sample
answer: Sphagnum moss is used as
protection for plants during shipping
and for potting material.) Have students make posters describing
their findings. l Visual
MISCONCEPTION
ALERT
Moss to the North Folklore says that
moss grows on the north side of trees.
But often, the green alga Pleurococcus,
not moss, thrives on the moist, shaded
(usually north) side of trees, stone walls,
and fences.
Answer to Reading Check
Sample answer: Nonvascular plants
are usually the first plants to live in
a new environment. They form a thin
layer of soil, where new plants can
grow. Nonvascular plants also prevent erosion.
Section 2 • Seedless Plants 305
Ferns
Reteaching -------------------------------------b
Plant Life Cycles Help students review the life cycles of
mosses and ferns. Ask students
to come up to the board individually and diagram a single
step of the life cycle for each
plant. l Visual
rhizome a horizontal, underground
stem that produces new leaves,
shoots, and roots
Ferns grow in many places, from the cold Arctic to warm,
humid tropical forests. Many ferns are small plants. But some
tropical tree ferns grow as tall as 24 m. Most ferns have a
rhizome. A rhizome is an underground stem from which new
leaves and roots grow. At first, fern leaves, or fronds, are tightly
coiled. These fronds look like the end of a violin, or fiddle.
So, they are called fiddleheads. You are probably most familiar
with the leafy fern sporophyte. The fern gametophyte is a tiny
plant about half the size of one of your fingernails. The fern
gametophyte is green and flat. It is usually shaped like a tiny
heart. The life cycle of ferns is shown in Figure 3.
Quiz ---------------------------------------------------------------------g
Horsetails and Club Mosses
1. What is the difference
Modern horsetails can be as tall as 8 m. But many horsetails
are smaller. They usually grow in wet, marshy places. Their
stems are hollow and contain silica. The silica gives horsetails
a gritty texture. In fact, early American pioneers referred to
horsetails as scouring rushes. They used horsetails to scrub pots
and pans. Horsetails and ferns have similar life cycles.
Club mosses are often about 20 cm tall. They grow in woodlands. Club mosses are not actually mosses. Unlike mosses,
club mosses have vascular tissue. The life cycle of club mosses
is similar to the fern life cycle.
between a rhizoid and a rhizome? (Sample answer: A rhizoid
is a rootlike structure that holds a
nonvascular plant in place. A rhizome is a horizontal underground
stem from which new roots and
shoots can grow.)
2. Describe the environmental
importance of mosses, liverworts, and hornworts. (Sample
answer: They are usually the first
plants to live in a new area.
When they die, they form a thin
layer of soil in which other plants
can grow. They also prevent soil
erosion, are eaten by some animals, and are used for nesting
material.)
Figure 3
Fern Life Cycle
c Spores land on moist
soil and grow into
gametophytes.
Gametophyte
Spores
Sperm
Egg
Female
Male
Alternative
Assessment ---------------------------g
Organizational Chart Have
students make a chart or Venn
diagram that describes the differences and similarities between
the seedless nonvascular and
seedless vascular plants discussed in this section. Have
students present their chart
to the class. l Logical/Verbal
b The sporophyte
releases spores
into the air.
Fertilized egg
Sporophyte
a The fertilized egg grows
into a sporophyte.
INCLUSION
Strategies
• Developmentally Delayed
• Visually Impaired
• Learning Disabled
Many students learn best when they
use their hands. Have students work in
groups of three or four. Assign a sporophyte to each group. Give each group
brown and green construction paper
and pipe cleaners. Have each group
create a model of their assigned
sporophyte. l Kinesthetic
306
d A sperm swims
through water to
fertilize an egg.
Chapter 12 • Introduction to Plants
h -----------------------------g
The Incredible, Edible Fern
Fiddleheads are a delicacy found in
the forests of the northeastern United States
during the spring. Edible fiddleheads are
actually the tightly coiled, emerging fronds
of the ostrich fern, Matteuccia struthiopteris.
Fiddleheads are also available commercially. Have interested students research
recipes for fiddleheads or prepare some
dishes for the class. l Verbal/Kinesthetic
PORTFOLIO
The Importance of Seedless Vascular Plants
Answers to Section Review
Seedless vascular plants play important roles in the environment. Ferns, horsetails, and club mosses help form soil. They
also help prevent soil erosion. In rocky areas, ferns can play
a role in the formation of communities. After lichens and
mosses create a layer of soil, ferns may take over. Ferns add
to soil depth, which allows other plants to grow.
Ferns and some club mosses are popular houseplants. The
fiddleheads of some ferns can be cooked and eaten. Young
horsetail shoots and their roots are also edible. Horsetails are
used in some dietary supplements, shampoos, and skin-care
products.
Seedless vascular plants that lived and died about 300 million years ago are among the most important to humans. The
remains of these ancient ferns, horsetails, and club mosses
formed coal. Coal is a fossil fuel that humans mine from the
Earth’s crust. Humans rely on coal for energy.
1. Sample answer: A moss plant
has a rhizoid, which anchors
the plant in soil. A fern has a
rhizome, or underground stem,
from which new leaves and
roots can grow.
2. d
3. Sample answer: Mosses cover
soil or rocks with a mat of tiny
green plants. Mosses have leafy
stalks and rhizoids. The gametophytes of liverworts are leafy
and mosslike or broad and flattened. Hornworts also have
broad, flattened gametophytes.
Most ferns are small, but some
tree ferns grow as tall as 24 m.
The fern gametophyte is often
very small and heart shaped.
Horsetails grow in wet, marshy
places and have hollow stems
that contain silica. Club mosses
are often about 20 cm tall and
grow in woodlands.
4. Sample answer: The remains
of seedless vascular plants that
lived about 300 million years ago
formed coal.
5. 3,980 cm (40 m ⫻ 100 cm/m ⫽
4,000 cm; 4,000 cm ⫺ 20 cm ⫽
3,980 cm)
6. Sample answer: Mosses, liverworts, and hornworts live in
damp areas. If the area dried
out, these plants would likely die.
7. Sample answer: Ferns, horsetails, and club mosses need
moisture. They may be smaller
today because there is less
moisture available. Also, competition from other plants might
have led to smaller ferns, horsetails, and club mosses.
✓Reading Check
Selling Plants
Imagine that you
work for an advertising agency.
Your next assignment is to
promote seedless vascular
plants. Write an advertisement
describing seedless vascular
plants and ways people benefit
from them. Your advertisement
should be exciting and
persuasive.
SKILL
How are seedless vascular plants important to
the environment?
Review
Summary
•
•
•
Nonvascular plants
include mosses, liverworts, and hornworts.
Seedless vascular plants
include ferns, horsetails,
and club mosses.
The rhizoids and rhizomes of seedless plants
prevent erosion by holding soil in place.
The remains of seedless
• vascular
plants that lived
and died about 300 million years ago formed
coal. Humans rely on
coal for energy.
Using Key Terms
Critical Thinking
1. Use each of the following terms
in a separate sentence: rhizoid
and rhizome.
Understanding Key Ideas
2. Seedless plants
a. help form communities.
b. reduce soil erosion.
c. add to soil depth.
d. All of the above
7. Applying Concepts Modern ferns, horsetails, and club
mosses are smaller than they
were millions of years ago. Why
might these plants be smaller?
3. Describe six kinds of seedless
plants.
4. What is the relationship
between coal and seedless
vascular plants?
Developed and maintained by the
National Science Teachers Association
Math Skills
5. Club mosses once grew as tall as
40 m. Now, they grow no taller
than 20 cm. What is the difference in height between ancient
and modern club mosses?
Answer to Reading Check
Sample answer: Seedless vascular plants
prevent erosion. They can grow in new soil
and add to the soil’s depth.
6. Making Inferences Imagine a
very damp area. Mosses cover
the rocks and trees in this area.
Liverworts and hornworts are
also very abundant. What might
happen if the area dries out?
Explain your answer.
For a variety of links related to this
chapter, go to www.scilinks.org
Topic: Seedless Plants
SciLinks code: HSM1368
CHAPTER RESOURCES
Chapter Resource File
CRF
• Section Quiz g
• Section Review g
• Vocabulary and Section Summary g
Section 2 • Seedless Plants 307
3
3
Overview
Students will learn the characteristics of seed plants and the
advantages of seeds over spores.
Students will also learn about
gymnosperms and angiosperms,
as well as the environmental
and economic importance of
these plants.
What You Will Learn
Describe three ways that seed plants
differ from seedless plants.
Describe the structure of seeds.
Compare angiosperms and gymnosperms.
Explain the economic and environmental importance of gymnosperms and angiosperms.
Vocabulary
Bellringer
pollen
pollination
Use the board or an overhead
projector to pose the following
question to students: “If plants
cannot move, how do they disperse their seeds?” (Sample
answer: Plants spread their seeds
by wind, water, and animals.)
Think about the seed plants that you use during the day. You
likely use dozens of seed plants, from the food you eat to the
paper you write on.
The two groups of vascular plants that produce seeds are gymnosperms and angiosperms. Gymnosperms are trees and shrubs
that do not have flowers or fruit. Angiosperms have flowers
and seeds that are protected by fruit.
Characteristics of Seed Plants
As with seedless plants, the life cycle of seed plants alternates
between two stages. But seed plants, such as the plant in
Figure 1, differ from seedless plants in the following ways:
• Seed plants produce seeds. Seeds nourish and protect young
sporophytes.
• Unlike
the gametophytes of seedless plants, the gametophytes of seed plants do not live independently of the
sporophyte. The gametophytes of seed plants are tiny. The
gametophytes form within the reproductive structures of
the sporophyte.
READING STRATEGY
Reading Organizer As you read
this section, make a table comparing
angiosperms and gymnosperms.
pollen the tiny granules that contain the male gametophyte of seed
plants
v--------------------------g
• The
sperm of seedless plants need water to swim to the
eggs of female gametophytes. The sperm of seed plants do
not need water to reach an egg. Sperm form inside tiny
structures called pollen. Pollen can be transported by wind
or by animals.
These three characteristics of seed plants allow them to
live just about anywhere. For this reason, seed plants are the
most common plants on Earth today.
✓
Reading Check List three characteristics of seed plants. (See the
Appendix for answers to Reading Checks.)
Seed Types Give students graystripe sunflower seeds, pumpkin
seeds, and wildflower seeds to
examine. Tell students to compare the seeds. Ask students how
seeds differ from spores. (Sample
answer: Seeds contain stored food.)
Ask students if they think it
would be easier to introduce
seed plants or seedless plants to
a new plot of land. (Sample
answer: If the land is dry, seed
plants would be more successful
than seedless plants.) l Visual
Figure 1 Dandelion fruits, which
each contain a seed, are spread
by wind.
CHAPTER RESOURCES
Chapter Resource File
CRF
• Lesson Plan
• Directed Reading A b
• Directed Reading B s
Technology
Transparencies
• Bellringer
Workbooks
Interactive Textbook Struggling Readers
308
Seed Plants
Chapter 12 • Introduction to Plants
Answer to Reading Check
Sample answer: Seed plants produce seeds.
The gametophytes of seed plants do not live
independently of the sporophyte. The sperm of
seed plants don’t need water to fertilize eggs.
Young
plant
Seed coat
Group
Stored food
in cotyledon
v -------g
MATERIAL S
FOR EACH GROUP
Figure 2 A seed contains
stored food and a young
plant, or sporophyte. A
seed is surrounded and
protected by a seed coat.
• cotton balls
• fan
• paper, construction
• scissors
• table
• tape, clear or masking
The Structure of Seeds
A seed forms after fertilization, when sperm and eggs are
joined. A seed is made up of three parts, as shown in Figure 2.
The first part is a young plant, or the sporophyte. The second part is stored food. It is often found in the cotyledons
(KAHT uh LEED uhnz), or the seed leaves of the young plant.
Finally, a seed coat surrounds and protects the young plant.
Seed plants have some advantages over seedless plants. For
example, when a seed begins to grow, the young plant uses the
food stored in the seed. The spores of seedless plants don’t have
stored food to help a new plant grow. Another advantage of
seed plants is that seeds can be spread by animals. The spores
of seedless plants are usually spread by wind. Animals spread
seeds more efficiently than the wind spreads spores.
✓Reading Check
Describe two advantages that seed plants have
over seedless plants.
Animals That
Help Plants Animals need plants to live, but
some plants benefit from
animals, too. These plants produce seeds with tough seed
coats. An animal’s digestive
system can wear down these
seed coats and speed the
growth of a seed. Identify a
plant that animals help in this
way. Then, find out how being
eaten by animals makes it possible for seeds to grow. Write
about your findings in your
science journal.
SKILL
Dissecting Seeds
1. Soak a lima bean seed in water overnight. Draw the seed
before placing it in the water.
2. Remove the seed from the water. Draw what you see.
3. The seed will likely look wrinkly. This is the seed coat. Use a
toothpick to gently remove the seed coat from the lima bean
seed.
4. Gently separate the halves of the lima bean seed. Draw what
you see.
5. What did you see after you split the lima bean seed in half?
6. What part of the seed do you think provides the lima bean
plant with the energy to grow?
Answer to Reading Check
A large number of plants in the heathland of South Africa produce seeds that
have an elaiosome, a very tasty covering
—tasty, that is, to ants, which carry
seeds into their underground colonies.
The ants nibble off the outside covering
and then leave the seed alone. The ants
plant the seed at just the right depth for
it to germinate successfully. Eventually,
the seed begins to grow.
Sample answer: Seeds have stored food to
nourish a young plant while spores do not.
Seeds can be spread by animals while spores
are spread by wind. Animals spread seeds more
efficiently than the wind does.
Seed Dispersal Have students
shred the cotton balls and place
the pieces on a table in front of
the fan. Turn on the fan, and
have students observe how far
the cotton “seeds” travel. Have
students wad a strip of tape into
a marble-sized ball and attach it
to the table. How far does the
ball move when subjected to the
“wind”? Ask students how they
think the seeds in this type of
fruit might best be transported.
(Sample answer: on an animal’s fur)
Have students cut a “maple
fruit” from construction paper.
Have students observe how this
“fruit” behaves in the wind.
l Kinesthetic/Visual
MATERIAL S
FOR EACH GROUP
• lima bean seed
• toothpick
• water
Teacher’s Notes: Use lima
bean seeds sold in packets for
use in gardens. Otherwise,
students may not see young
sporophytes.
Answers
5. Students will likely see the
young sporophyte.
6. Sample answer: Food is stored
in the two halves of the seed.
Section 3 • Seed Plants 309
Gymnosperms
Seed plants that do not have flowers or fruit are called gymnosperms. Gymnosperm seeds are usually protected by a cone.
The four groups of gymnosperms are conifers, ginkgoes, cycads,
and gnetophytes (NEE toh FIETS). You can see some gymnosperms in Figure 3.
Discussion --------------------------------------b
Gymnosperms Many students
are already familiar with conifers, such as pine trees but may
suddenly feel confused when the
term gymnosperm is introduced.
Encourage these students to list
the characteristics they have
observed in pine trees. (Sample
answers: stay green all year; thin,
needle-shaped leaves; pine cones)
Stress that even though this section provides additional information about gymnosperms,
students already know a great
deal about them. l Verbal
The Importance of Gymnosperms
Conifers are the most economically important gymnosperms.
People use conifer wood for building materials and paper
products. Pine trees produce a sticky fluid called resin. Resin
is used to make soap, turpentine, paint, and ink. Some conifers produce an important anticancer drug. Some gnetophytes
produce anti-allergy drugs. Conifers, cycads, and ginkgoes are
popular in gardens and parks.
Figure 3
Examples of Gymnosperms
Using the Figure -----g
Some Common Gymnosperms
Have students work in pairs. Ask
students to examine Figure 3.
Students should take turns summarizing the information in
the figure aloud. Their partners
should stop them if they find
the information confusing or
need clarification.
l Verbal/ Interpersonal
h -----------------------------a
Gnetophytes Gnetophytes have many
things in common with
angiosperms. Some scientists
believe that the two are closely
related. Ask interested students
to research and write a report
about the similarities between
gnetophytes and angiosperms
and about the theories for these
similarities. l Verbal
Writing
Conifers The conifers, such as this
ponderosa pine, are
the largest group
of gymnosperms.
There are about 550
species of conifers.
Most conifers are
evergreens that
keep their needleshaped leaves all
year. Conifer seeds
develop in cones.
Ginkgoes Today,
there is only one
living species of
ginkgo, the ginkgo
tree. Ginkgo seeds
are not produced
in cones. The
seeds have fleshy
seed coats and are
attached directly to
the branches of
the tree.
Cycads The
cycads were more
common millions
of years ago. Today,
there are only
about 140 species
of cycads. These
plants grow in the
Tropics. Like conifer
seeds, cycad seeds
develop in cones.
Gnetophytes About
70 species of gnetophytes, such as this
joint fir, exist today.
Many gnetophytes
are shrubs that grow
in dry areas. The
seeds of most gnetophytes develop
in cones.
CONNECTION v
Earth Science ----------------------a
Growth Rings Geochronology, the interpretation and dating of the geologic record,
includes dendrochronology, which is the
study of trees’ growth rings. Bristlecone
pines have been particularly useful in this
endeavor because many of them are very
old. Ask interested students to research
how scientists date trees and use them
for geochronology. Ask students to present
their findings to the class. l Verbal
310
Chapter 12 • Introduction to Plants
When scientists compared radiocarbon
dates of bristlecone pines with dates
obtained from tree-ring patterns, they
discovered that their calibrations for
carbon-14 analysis were incorrect. The
new data indicated that some wooden
artifacts found in Europe were 1,000
years older than originally thought. The
bristlecone pines became known as the
“trees that rewrote history.”
Discussion ----------------------------------g
Pine Life Cycle
Figure 4
Gametophyte
Fertilized egg
c Sex cells are
produced in
the cones.
Egg
Female cone
(cross section)
d Wind carries pollen to the egg. A
sperm from a pollen grain fertilizes
the egg.
Pollen
Male cone
(cross section)
b Spores are
produced.
They grow into
gametophytes.
Male cones
Seed
e The fertilized egg
develops into
a young sporophyte within
a seed.
a The seed contains a young
sporophyte, which grows
into an adult sporophyte.
Female cones
Sporophyte
Gymnosperm Life Cycle
The gymnosperms that are most familiar to you are probably
the conifers. The word conifer comes from two words that mean
“cone-bearing.” Conifers have two kinds of cones—male cones
and female cones. The spores of each kind of cone become
tiny gametophytes.
The male gametophytes of gymnosperms are found in pollen. Pollen contain sperm. The female gametophytes produce
eggs. Wind carries pollen from the male cones to the female
cones. This transfer of pollen from the male cones to the
female cones is called pollination. The female cones can be on
the same plant. Or, they can be on a different plant of the
same species.
Sperm from pollen fertilize the eggs of the female cone.
A fertilized egg develops into a young sporophyte within the
female cone. The sporophyte is surrounded by a seed. Eventually, the seed is released. Some cones release seeds right away.
Other cones release seeds under special circumstances, such
as after forest fires. If conditions are right, the seed will grow.
The life cycle of a pine tree is shown in Figure 4.
✓Reading Check
l Verbal
INCLUSION
Strategies
pollination the transfer of pollen
from the male reproductive structures to the female structures of seed
plants
Describe the gymnosperm life cycle.
SUPPORT FOR
English Language Learners
Paraphrase To reinforce and check
comprehension, have students recreate
the diagram showing the pine life cycle
on this page in their science journals.
They should substitute their own words
to describe the process. When they have
finished, ask them to compare their
diagrams in groups of 3 students to
ensure accuracy. Spot-check diagrams
in each group, and request corrections
as necessary. Students should save their
diagrams for future reference. l Visual/
Verbal/Interpersonal
Good Fires Ask students what
factors they think are necessary
for a gymnosperm to germinate.
(Sample answers: air, sunlight,
water, and soil) Tell students that
the cones of jack pines must
burn to open. Explain that jack
pines were once numerous, but
their numbers have been greatly
reduced in recent years. Ask students to explain why there are
fewer jack pines today. (Sample
answer: Today, many forest fires are
put out, especially those that are
near towns and housing developments.) Tell students that the
Kirtland’s warbler nests only
in young jack pines, and ask
students what they think has
happened to the warbler’s population. (Sample answer: If there are
fewer jack pines, then there are
likely fewer Kirtland’s warblers.)
Answer to Reading Check
Sample answer: Sperm from the male cone fertilize the eggs of the female cone. A fertilized
egg develops into a young sporophyte surrounded by a seed within the female cone.
Eventually, seeds are released from the cone.
• Learning Disabled
• Developmentally Delayed
• Hearing Impaired
Transferring learning from
the classroom to the real
world is important. Ask students to bring to class a piece
of an angiosperm and a piece
of a gymnosperm. (If students cannot bring pieces of
the plants, ask them to bring
information about specific
angiosperms and gymnosperms.) Place a chart on the
board with these headings:
Kind of plant (if known),
Height, Width, Description
of leaves, and Type of plant
(angiosperm or gymnosperm). Ask students to add
information to the chart.
l Logical/Verbal
Section 3 • Seed Plants 311
Angiosperms
Vascular plants that produce flowers and fruits are called angiosperms. Angiosperms are the most abundant plants today. There
are at least 235,000 species of angiosperms. Angiosperms can
be found in almost every land ecosystem.
Reteaching -------------------------------------b
Seed Plants Write the following on the board: gymnosperms,
angiosperms, monocots, and
dicots. Ask students to give an
example and a description of
each. l Verbal
Angiosperm Reproduction
Flowers help angiosperms reproduce. Some angiosperms depend
on the wind for pollination. But others have flowers that attract
animals. As shown in Figure 5, when animals visit different
flowers, the animals may carry pollen from flower to flower.
Fruits surround and protect seeds. Some fruits and seeds
have structures that help the wind carry them short or long
distances. Other fruits attract animals that eat the fruits. The
animals discard the seeds away from the plant. Some fruits,
such as burrs, are carried from place to place by sticking to
the fur of animals.
Quiz ---------------------------------------------------------------------g
1. How are gymnosperms and
angiosperms different?
(Sample answer: Angiosperms
have flowers for reproduction
and fruits to protect the seeds.
Gymnosperms often have gametophytes and seeds enclosed in
cones.)
2. How are flowering plants
important? (Sample answer:
Flowering plants provide land animals with the food they need to
survive, either directly or indirectly. Major crops are flowering
plants. Flowering plants are also
used for building materials and to
make clothing, rope, medicines,
perfumes, and rubber.)
✓Reading Check
Why do angiosperms have flowers and fruits?
Two Kinds of Angiosperms
Angiosperms are divided into two classes—monocots and
dicots. The two classes differ in the number of cotyledons, or
seed leaves, their seeds have. Monocot seeds have one cotyledon. Grasses, orchids, onions, lilies, and palms are monocots.
Dicot seeds have two cotyledons. Dicots include roses, cactuses, sunflowers, peanuts, and peas. Other differences between
monocots and dicots are shown in Figure 6.
Figure 5 This bee is on its way
to another squash flower, where
it will leave some of the pollen it
is carrying.
Figure 6
Two Classes of Angiosperms
Dicots
Monocots
Leaves with
parallel veins
Alternative
Assessment ---------------------------a
Leaves with
branching veins
Flower
parts in
threes
Concept Mapping Have students organize the following
terms into a concept map: seed
plants, gymnosperms, angiosperms, flowers, fruits, conifers,
cycads, monocots, dicots, gnetophytes, and ginkgoes. l Logical/
One cotyledon
(seed leaf)
Flower
parts in
fours or
fives
Bundles of
vascular tissue
are scattered.
Two cotyledons
(seed leaves)
Bundles of
vascular tissue
are in a ring.
Visual
Answer to Reading Check
Sample answer: Flowers help angiosperms
reproduce. Fruits surround and protect the
seeds. Some fruits attract animals, which
spread the seeds.
312
Chapter 12 • Introduction to Plants
INTERNET v
Essay -----------------------------------------------------------------------g
For an internet activity related to this
chapter, have students go to go.hrw.com
and type in the keyword HL5PL1W.
The Importance of Angiosperms
Answers to Section Review
Flowering plants provide many land animals with the food they
need to survive. A field mouse that eats seeds and berries is
using flowering plants directly as food. An owl that eats a field
mouse is using flowering plants indirectly as food.
People use flowering plants in many ways. Major food crops,
such as corn, wheat, and rice, are flowering plants. Some flowering plants, such as oak trees, are used for building materials.
Flowering plants, such as cotton and flax, are used to make clothing and rope. Flowering plants are also used to make medicines,
rubber, and perfume oils.
1. Sample answer: Pollen contains
the male gametophyte of seed
plants. Pollination happens when
pollen is transferred from male
structures to female structures.
2. d
3. c
4. Sample answer: Seeds are made
up of three parts. The first part is
the young plant. The second part
is stored food, often found in the
cotyledons. The third part is the
seed coat, which surrounds and
protects the young plant.
5. Sample answer: Most conifers
are evergreens that have seeds
in cones. Cycads grow in the
tropics and have seeds in cones.
There is only one species of
gingko, which produces its seeds
in fleshy seed coats attached to
the branches of the tree.
Gnetophytes are often shrubs
that grow in dry areas, and most
gnetophytes have seeds in
cones. Conifers are the largest
and most economically important
group of gymnosperms.
6. Sample answer: Gymnosperms
and angiosperms are both seed
plants, but gymnosperms do not
have flowers or fruits as angiosperms do. Instead, gymnosperms often have cones.
7. 265,000 ⫺ 235,000 ⫽
30,000 plants; 30,000 ⫼
265,000 ⫻ 100 ⫽ 11.3%
8. Sample answer: Flowers attract
pollinators, which carry pollen to
the flowers. Some flowers are
adapted for the wind to spread
pollen. Fruits protect the seeds,
but fruits also attract animals or
stick to animals’ fur. Being eaten
and sticking to fur both help to
spread seeds.
9. Sample answer: The plant does
not get much wind to spread its
seeds, so it likely relies on animals to spread its seeds.
Because there are herbivores in
the area, the plant may have
sweet fruits to attract the animals. The animals could eat the
fruits and spread the seeds.
✓Reading Check
How are flowering plants important to humans?
Review
Summary
•
•
•
•
For another activity related
to this chapter, go to
go.hrw.com and type in the
keyword HL5PL1W.
Seeds nourish the
young sporophyte of
seed plants. Seed plant
gametophytes rely on
the sporophyte. Also,
they do not need water
for fertilization.
Seeds nourish a young
plant until it can make
food by photosynthesis.
Gymnosperms do not
have flowers or fruits.
Gymnosperm seeds are
usually protected by
cones. Gymnosperms
are used for building
materials, paper, resin,
and medicines.
Angiosperms have flowers and fruits. Angiosperms are used for
food, medicines, fibers
for clothing, rubber, and
building materials.
Using Key Terms
Math Skills
1. In your own words, write a definition for each of the following
terms: pollen and pollination.
Understanding Key Ideas
2. One advantage of seed plants is
that
a. seed plants grow in few
places.
b. they can begin photosynthesis
as soon as they begin to grow.
c. they need water for
fertilization.
d. young plants are nourished by
food stored in the seed.
3. The gametophytes of seed plants
a. live independently of the
sporophytes.
b. are very large.
c. are protected in the reproductive structures of the
sporophyte.
d. None of the above
7. More than 265,000 species of
plants have been discovered.
Approximately 235,000 of those
species are angiosperms. What
percentage of plants are NOT
angiosperms?
Critical Thinking
8. Making Inferences In what
ways are flowers and fruits adaptations that help angiosperms
reproduce?
9. Applying Concepts An angiosperm lives in a dense rainforest,
close to the ground. It receives
little wind. Several herbivores
live in this area of the rainforest.
What are some ways the plant
can ensure its seeds are carried
throughout the forest?
Developed and maintained by the
National Science Teachers Association
4. Describe the structure of seeds.
5. Briefly describe the four groups of
gymnosperms. Which group is
the largest and most economically important?
For a variety of links related to this
chapter, go to www.scilinks.org
Topic: Plants with Seeds
SciLinks code: HSM1168
6. Compare angiosperms and
gymnosperms.
Answer to Reading Check
Sample answer: Major food crops are flowering
plants. Flowering plants provide building
material, are used to make clothing and rope,
and are used to make medicines, rubber, and
perfume oils.
CHAPTER RESOURCES
Chapter Resource File
CRF
• Section Quiz g
• Section Review g
• Vocabulary and Section Summary g
• Reinforcement Worksheet b
Technology
Transparencies
• L41 Two Classes of Angiosperms
Workbooks
Science Skills
• Science Writing g
Section 3 • Seed Plants 313
4
Structures of Seed Plants
4
You have different body systems that carry out many functions.
Plants have systems too—a root system, a shoot system, and a
reproductive system.
Overview
In this section, students will
learn about the structures and
the functions of a plant’s root
and shoot systems. Finally, students will learn about the parts
of a flower and explain their
functions.
What You Will Learn
List three functions of roots and
three functions of stems.
Describe the structure of a leaf.
Identify the parts of a flower and
their functions.
Vocabulary
xylem
phloem
sepal
petal
Bellringer
Show students a cactus. Point
out the spines, and ask students
to identify them and explain
their purpose. (Sample answer:
Cactus spines are modified leaves
that help protect the plant from
grazing animals.)
stamen
pistil
ovary
READING STRATEGY
Mnemonics As you read this section,
create a mnemonic device to help
you remember the parts of a plant.
A plant’s root system and shoot system supply the plant with
what it needs to survive. The root system is made up of roots.
The shoot system includes stems and leaves.
The vascular tissues of the root and shoot systems are
connected. There are two kinds of vascular tissue—xylem
(ZIE luhm) and phloem (FLOH EM). Xylem is vascular tissue
that transports water and minerals through the plant. Xylem
moves materials from the roots to the shoots. Phloem is vascular
tissue that transports food molecules to all parts of a plant.
Xylem and phloem are found in all parts of vascular plants.
Roots
Most roots are underground, as shown in Figure 1. So, many
people do not realize how extensive root systems can be. For
example, a corn plant that is 2.5 m tall can have roots that
grow 2.5 m deep and 1.2 m out and away from the stem!
Root Functions
The following are the three main functions of roots:
• Roots
supply plants with water and dissolved minerals.
These materials are absorbed from the soil. The water and
minerals are transported to the shoots in the xylem.
xylem the type of tissue in vascular plants that provides support and
conducts water and nutrients from
the roots
Demonstration --------------g
Roots Bring several plants to
class. Gently remove each plant
from its pot, and show the roots
to the class. Ask students to
identify whether each plant
has a taproot system or a fibrous
root system. Point out any structures that are not roots but are
found underground, such as
tubers and bulbs (modified
stems). Then, ask students to list
three functions of roots. (Sample
answer: Roots supply plants with
water and dissolved minerals. Roots
hold plants securely in the soil, and
roots store surplus
e
food.) l Visual
phloem the tissue that conducts
food in vascular plants
hold plants securely in the soil.
store surplus food made during photosynthesis. The
food is produced in the leaves. Then, it is transported in
the phloem to the roots. In the roots, the surplus food is
usually stored as sugar or starch.
Figure 1 The roots of these plants
provide the plants with water and
minerals.
Onion
CHAPTER RESOURCES
Chapter Resource File
CRF
• Lesson Plan
• Directed Reading A b
• Directed Reading B s
Technology
Transparencies
• Bellringer
• L42 The Structures of a Root
Workbooks
Interactive Textbook Struggling Readers
Science Skills
• Taking Notes g
314
• Roots
• Roots
Chapter 12 • Introduction to Plants
Dandelion
Carrots
Is That a Fact!
The deepest roots ever discovered
belonged to a wild fig tree in South
Africa. The roots had penetrated the soil
to a depth of more than 120 m.
Root Structure
The structures of a root are shown in Figure 2. The layer of
cells that covers the surface of roots is called the epidermis.
Some cells of the epidermis extend from the root. These cells,
or root hairs, increase the surface area of the root. This surface
area helps the root absorb water and minerals. After water and
minerals are absorbed by the epidermis, they diffuse into the
center of the root, where the vascular tissue is located.
Roots grow longer at their tips. A group of cells called the
root cap protects the tip of a root. The root cap produces a
slimy substance. This substance makes it easier for the root to
push through soil as it grows.
Root Systems
There are two kinds of root systems—taproot systems and
fibrous root systems. A taproot system has one main root, or
a taproot. The taproot grows downward. Many smaller roots
branch from the taproot. Taproots can reach water deep
underground. Dicots and gymnosperms usually have taproot
systems.
A fibrous root system has several roots that spread out from
the base of a plant’s stem. The roots are usually the same size.
Fibrous roots usually get water from close to the soil surface.
Monocots usually have fibrous roots.
Answer to Math Practice
about 10% (15,600 ⫹ 12,000 ⫽ 27,600
seedless plants; 15,600 ⫹ 12,000 ⫹
760 ⫹ 235,000 ⫽ 263,360 total plants;
27,600 ⫼ 263,360 ⫻ 100 ⫽ 10.4%)
Practice with Percentages
The following table gives an
estimate of the number of
species in each plant group.
Plant Species
Plant group
Number
of species
Mosses, liverworts, and
hornworts
15,600
Ferns, horsetails, and club
mosses
12,000
Gymnosperms
760
Angiosperms
235,000
FOR EACH GROUP
• bags, plastic, resealable (4)
• ruler, metric
• seed, four varieties, 1 seed each
• towels, paper (4)
• water
What percentage of plants do
not produce seeds?
✓
The Structures of a Root
A root absorbs water and minerals, which move
into the xylem. Growth occurs at the tip of a
root. The root cap releases a slimy substance
that helps the root grow through soil.
Xylem
Phloem
Root
cap
MISCONCEPTION
ALERT
Tubers Students may think potatoes
are the roots of the potato plant. Though
they grow underground, potatoes are
not roots. They are modified stems
called tubers.
v -----------b
MATERIAL S
Reading Check What are two types of root systems? (See the
Appendix for answers to Reading Checks.)
Figure 2
Group
Answer to Reading Check
taproot systems and fibrous root systems
Root Growth Have students
work in groups of four. Tell students to fold a paper towel in
quarters, placing a seed in the
fold of the towel. Students
should moisten the paper towel
thoroughly, but the paper towel
should not be dripping. Tell students to place paper towels in a
plastic bag. For each day of the
next week, have students measure the length of the roots that
develop. Students should
moisten the paper towel as
needed during the week.
Students should also observe the
roots each day for changes in
appearance. Ask students to
make a chart of their measurements. Then, ask students the
following questions: “What did
you notice about the appearance
of your roots at they grew?” (Students may notice that the roots grew
root hairs or became more numerous.
Some students may also note that
the tips of the roots seemed slimy.)
“Which of your seeds grew
the fastest?” (Answers may vary
depending on the varieties of seeds
used.) At the end of the experiment, consider asking students
to plant their seeds in potting
soil to see how the roots continue to develop. l Kinesthetic
Section 4 • Structures of Seed Plants 315
Stems
Stems vary greatly in shape and size. Stems are usually located
above ground. However, many plants have underground stems.
The trunk of the valley oak in Figure 3 is a stem.
v----------------------------b
Stem Functions Have students
draw pictures that illustrate the
functions of stems. Tell them
to write captions for each
illustration. l Visual/Verbal
Stem Functions
A stem connects a plant’s roots to its leaves and flowers. A
stem also has the following functions:
• Stems
support the plant body. Leaves are arranged along
stems or on the ends of stems. This arrangement helps leaves
get sunlight for photosynthesis. Stems hold up flowers,
which helps pollinators, such as bees, see the flowers.
CONNECTION v
History ------------------------------------------------a
Using Stems The stems of
many large aquatic grasses are
called reeds. After reeds are
harvested and dried, they can
be used to construct many useful products. For thousands of
years, arrows, pens, baskets,
musical instruments, furniture,
and houses have been made
out of reeds. Building boats
from reeds is an ancient craft
that is still practiced in some
places where reeds are plentiful. Ancient Egyptian buildings
include friezes of oceangoing
ships made of reeds. In the
1960s, a Norwegian explorer
named Thor Heyerdahl wondered if a reed ship could
have provided ancient peoples
with transportation across the
Atlantic Ocean. To demonstrate
that such a journey was possible, he had Bolivian craftspersons build a traditional reed
vessel, the Ra II. Ask students
to research Heyerdahl and the
Ra II. Have interested students
make a model of Heyerdahl’s
reed vessel. l Kinesthetic
• Stems transport materials between the root system and the
shoot system. Xylem carries water and dissolved minerals
from the roots to the leaves and other shoot parts. Phloem
carries the food made during photosynthesis to roots and
other parts of the plant.
• Some stems store materials. For example, the stems of cactuses and some trees are adapted for water storage.
Figure 3 The stem, or trunk, of
this valley oak keeps the tree
upright, which helps leaves get
sunlight for photosynthesis.
Herbaceous Stems
Many plants have stems that are soft, thin, and flexible. These
stems are called herbaceous stems (huhr BAY shuhs STEMZ).
Examples of plants that have herbaceous stems include wildflowers, such as clovers and poppies. Many crops, such as beans,
tomatoes, and corn, have herbaceous stems. A cross section of
an herbaceous stem is shown in Figure 4.
✓
Reading Check What are herbaceous stems? Give an example
of a plant that has an herbaceous stem.
Figure 4
Cross Section of an Herbaceous Stem
Buttercups are just one plant that has herbaceous
stems. Wildflowers and many vegetables have soft,
thin, and flexible stems.
Phloem
Xylem
Is That a Fact!
Linen is a fabric woven from the long
fibers harvested from the stems of flax
plants. Humans have used linen fabrics
for over 10,000 years.
316
Chapter 12 • Introduction to Plants
Answer to Reading Check
Sample answer: Herbaceous stems are soft,
thin, and flexible. Poppies have herbaceous
stems.
Figure 5
v--------------------------------------g
Cross Section of a Woody Stem
Analyzing Tree Rings Have
students examine preserved
cross sections of trees that
clearly show growth rings. Ask
students to identify the xylem
and phloem rings. (Students
should recognize that phloem compose the innermost part of bark.
Xylem form the growth rings of the
center of the stem.) Ask students
to measure the width of each
ring and to interpret the measurements. Have them take into
account the growing conditions
in the spring and summer. (Students may recognize dry years
and wet years based on these
measurements.)
Some plants, such as these trees, have woody
stems. Plants that have woody stems usually live
for many years. People can use growth rings to
estimate the age of a plant.
Growth
ring
Phloem
Xylem
Woody Stems
Trees and shrubs have rigid stems made of wood and bark.
These stems are called woody stems. Figure 5 shows a cross section of a woody stem. Trees or shrubs that live in areas with
cold winters have a growing period during the spring and summer. These plants have a dormant period during the winter.
At the beginning of each growing period, large xylem cells
are produced. As fall approaches, the plants produce smaller
xylem cells, which appear darker. In the fall and winter, the
plants stop producing new cells. The cycle begins again the
next spring. A ring of dark cells surrounding a ring of light
cells makes up a growth ring.
l Visual
e
Leaves
Leaves vary greatly in shape. They may be round, narrow,
heart-shaped, or fan-shaped. Leaves also vary in size. The raffia palm has leaves that may be six times longer than you are
tall. The leaves of duckweed, a tiny aquatic plant, are so small
that several of the leaves can fit on your fingernail. Figure 6
shows a poison ivy leaf.
Leaf Functions
The main function of leaves is to make food for the plant.
Chloroplasts in the cells of leaves capture energy from sunlight.
The leaves also absorb carbon dioxide from the air. The leaves
use the captured energy to make food, or sugar, from carbon
dioxide and water.
Figure 6 The leaves of poison
ivy are very distinctive. They
make food to help the plant
survive.
CHAPTER RESOURCES
Technology
Garlic bulbs are fleshy, nutrient-storing
structures composed of modified leaves
and a stem. Garlic has a pungent flavor
and is often used to season foods.
Sometimes, garlic is used as a nutritional supplement. At the annual Gilroy
Garlic Festival in Gilroy, California, visitors can purchase garlic ice cream and
garlic candy.
Transparencies
• L42 Cross Section of an Herbaceous Stem;
Cross Section of a Woody Stem
Section 4 • Structures of Seed Plants 317
Figure 7
Group
v
The Structure of a Leaf
Leaf cells are arranged in layers. These
layers allow the leaf to work efficiently.
-------g
MATER IAL S
FOR EACH GROUP
Cuticle
• books, heavy
• leaves
• newspapers
• notebook or index cards
• paper towels
• tape, transparent
Palisade layer
Spongy layer
Safety Caution: Tell students to
avoid plants such as poison ivy
and poison oak during this
activity. You may want to show
students pictures of these plants.
Leaf Collecting Challenge students to see how many different
types of leaves they can collect.
Students should press the leaves
for a few days after collecting
them. They can do this by placing each leaf between two paper
towels and several sheets of
newspaper on each side. Then,
students should stack heavy
books on top of the leaf. When
the leaf is flat and dry, have students tape the leaves to cards or
to the pages of a notebook. Have
students use reference books to
identify the names of the plants
from which they collected the
leaves. Have students label each
leaf with the common name,
the scientific name, the date on
which the leaf was collected,
and the location where the leaf
was found.
l Kinesthetic
Upper epidermis
Lower epidermis
Xylem
Phloem
Guard cells
Stoma
Vascular tissue
Cuticle
Leaf Structure
Looking at Leaves
Leaves are many shapes and
sizes. They are also arranged
on a stem in many ways.
Walk around your home. In
your science journal, sketch
the leaves of the plants you
see. Notice how the leaves
are arranged on the stem,
the shapes of the leaves, and
the veins in the leaves. Use a
ruler to measure the size of
the leaves.
e
The structure of leaves, shown in Figure 7, is related to their
main function—photosynthesis. The outer surfaces of a leaf
are covered by a cuticle. The cuticle prevents water loss from
the leaf. A single layer of cells, the epidermis, lies beneath the
cuticle. Light passes through the epidermis. Tiny openings in
the epidermis, called stomata (singular, stoma), let carbon dioxide enter the leaf. Guard cells open and close the stomata.
Most photosynthesis takes place in the middle of a leaf. This
part of a leaf often has two layers. Cells in the upper layer, the
palisade layer, contain many chloroplasts. Photosynthesis takes
place in the chloroplasts. Carbon dioxide moves freely in the
space between the cells of the second layer, the spongy layer.
Xylem and phloem are also found in the spongy layer.
✓Reading Check
What are the cell layers of a leaf?
Leaf Adaptations
Some leaves have functions other than photosynthesis. For
example, the leaves of many cactuses are modified as spines.
These spines keep animals from eating the cactuses. The leaves
of another plant, the sundew, are modified to catch insects.
Sundews grow in soil that does not contain enough nitrogen
to meet the plants’ needs. By catching and digesting insects,
a sundew is able to get enough nitrogen.
Answer to Reading Check
epidermis, palisade layer, and spongy layer
SUPPORT FOR
English Language Learners
Plant Structure A cooperative learning strategy will help students process
the information in this section. When
students have finished reading, place
them in groups of 4. In each group, one
person is responsible for explaining one
part of the plant to the group. Students
should note the main ideas presented
for each part in a four-column table.
Later, invite the groups to contribute
to a class table to check for accuracy.
l Verbal/Interpersonal
318
Chapter 12 • Introduction to Plants
Discussion ----------------------------------g
Flowers
Most people admire the beauty of flowers, such as the wildflowers in Figure 8. But why do plants have flowers? Flowers
are adaptations for sexual reproduction.
Flowers come in many shapes, colors, and fragrances.
Brightly colored and fragrant flowers usually rely on animals
for pollination. For example, some flowers look and smell like
rotting meat. These flowers attract flies. The flies pollinate the
flowers. Plants that lack brightly colored flowers and fragrances,
such as grasses, depend on the wind to spread pollen.
Many flowers also produce nectar. Nectar is a fluid that
contains sugar. Nectar attracts birds and insects. These animals
move from flower to flower and drink the nectar. As they do
so, they often carry pollen to the flowers.
sepal in a flower, one of the outermost rings of modified leaves that
protect the flower bud
petal one of the ring or rings of the
usually brightly colored, leaf-shaped
parts of a flower
Sepals and Petals
Flowers usually have the following basic parts: sepals, petals,
stamens, and one or more pistils. The flower parts are usually
arranged in rings around the central pistil.
Sepals are modified leaves that make up the outermost ring
of flower parts and protect the bud. Sepals are often green like
other leaves. Sepals cover and protect the flower while it is
a bud. As the blossom opens, the sepals fold back. Then, the
petals can unfold and become visible. Petals are broad, flat,
thin leaflike parts of a flower. Petals vary greatly in color and
shape. Petals attract insects or other animals to the flower.
These animals help plants reproduce by carrying pollen from
flower to flower.
Attracting Pollinators Discuss
that flowers serve an important
purpose for plants. Ask students
to read the material about flowers and to consider how the following factors make flowers
successful in the plant world:
color, shape, and smell. (Sample
answers: The color of a flower may
attract insects. The shape of a
flower may be adapted for a specific pollinator, such as a a hummingbird. Or the shape may help
the flower spread pollen by the
wind. The fragrance of a flower is
designed to attract pollinators. For
example, flies are drawn to badsmelling flowers.) l Verbal
h -----------------------------g
Pointy Plants A cactus’s
spines are modified
leaves. Other plants have
sharp projections to protect
them. Roses have prickles. The
hawthorn tree has thorns. Have
students write a report about
“painful” plant parts. Their
report should state whether the
projection is a modified leaf or
another physical structure.
Writing
Figure 8 Many flowers help the
plants reproduce by attracting
pollinators with bright petals and
strong fragrances.
l Verbal
CONNECTION to
Earth Science ----------------------a
Is That a Fact!
The more water-repellent a leaf is, the
healthier it may be, according to some
scientists. Dirt, which contains diseasecausing microbes, has a stronger attraction to water droplets than to a leaf’s
surface. When the water rolls off the
leaf, so do the dirt and microbes. Water
repellency thus helps prevent infection.
CHAPTER RESOURCES
Technology
Transparencies
• L44 The Structure of a Leaf
• LINK TO PHYSICAL SCIENCE P92 The
Electromagnetic Spectrum
Electromagnetic Spectrum
Photosynthesis is the process
by which plants convert light
energy to chemical energy. The
light energy that plants use is
only a small part of the electromagnetic spectrum. Use the
teaching transparency entitled
“The Electromagnetic Spectrum”
to help students understand that
plants use the visible-light portion of the electromagnetic
spectrum for photosynthesis.
l Visual
Section 4 • Structures of Seed Plants 319
Figure 9
Reteaching
The Structure of a Flower
The stamens, which produce pollen, and the pistil,
which produces eggs, are surrounded by the petals
and the sepals.
----------------------------------b
Flower Parts Ask student volunteers to describe a flower part
and to draw that part on the
board. Continue until students
have drawn a complete flower.
Stigma
Style
l Visual
Quiz ---------------------------------------------------------------------g
Ovule
1. Why do some plants have
Ovary
brightly colored flowers and
other plants do not? (Sample
answer: Plants with brightly
colored flowers usually attract
animals for pollination. Plants
without showy flowers usually
rely on the wind for pollination.)
l Logical/Verbal
320
Stigma
Style
Ovary
Anther
Filament
Pistil
Ovule
Stamens and Pistils
stamen the male reproductive
structure of a flower that produces
pollen and consists of an anther at
the tip of a filament
pistil the female reproductive part
of a flower that produces seeds
and consists of an ovary, style, and
stigma
ovary in flowering plants, the lower
part of a pistil that produces eggs in
ovules
Alternative
Assessment ---------------------------g
Eating Plants Have students
list ingredients for a salad.
(Sample answers: lettuce, tomato,
cucumber, carrot, cabbage, broccoli, alfalfa sprouts, and garbanzo
beans) Ask students to identify
the part of the plant that is
eaten. (Sample answer: Lettuce and
cabbage come from leaves. Tomato
and cucumber are fruits. Carrots are
roots. Broccoli are flowers. Alfalfa
sprouts are root, stem, and leaf.
Garbanzo beans are seeds.)
Stamen
Sepal
2. Describe the two types of
root systems, and list one
plant that has each type.
(A taproot system has one main
root. Carrots have a taproot.
Fibrous root systems include
many roots of a similar size that
grow from the base of the stem.
Onions have fibrous roots.)
Petal
As you can see in Figure 9, the stamens of flowers are usually
found just above the petals. A stamen is a male reproductive
structure of flowers. Each stamen has a thin stalk called a filament. The filament is topped by an anther. Anthers are saclike
structures that produce pollen.
Found in the center of most flowers is one or more pistils.
A pistil is the female reproductive structure of flowers. The
tip of the pistil is called the stigma. Pollen grains collect on
stigmas, which are often sticky or feathery. The long, slender
part of the pistil is the style. The rounded base of a pistil that
contains one or more ovules is called the ovary. Each ovule
contains an egg. When the egg is fertilized, the ovule develops
into a seed. The ovary develops into a fruit.
✓
Reading Check Describe stamens and pistils. Which are the
female parts of a flower? the male parts of a flower?
The Importance of Flowers
Flowers help plants reproduce. Humans also use flowers for
many things. Roses and many other flowers are used for floral arrangements. Some flowers, such as artichokes, broccoli,
and cauliflower, can be eaten. Other flowers, such as hibiscus
and chamomile flowers, are used to make tea. Flowers used
as spices include cloves and saffron. Flowers are also used in
perfumes, lotions, and shampoos.
Answer to Reading Check
Sample answer: Stamens, which have filaments
topped by anthers, are the male reproductive
parts of flowers. A pistil is the female part of
a flower. A pistil has a stigma, style, and ovary.
Chapter 12 • Introduction to Plants
Review
Summary
supply plants with water and dis• Roots
solved minerals. They support and anchor
Most photosynthesis takes place in the pal• isade
layer of a leaf. The spongy layer of a
plants. Roots also store surplus food made
during photosynthesis.
support the body of a plant. They
• Stems
allow transport of material between the
•
root system and shoot system. Some
stems store materials, such as water.
A leaf has a thin epidermis on its upper
and lower surfaces. The epidermis allows
sunlight to pass through to the center of
the leaf.
leaf allows the movement of carbon dioxide and contains the xylem and phloem.
The four main parts of a flower are the
• sepals,
the petals, the stamens, and one or
•
more pistils.
Flowers are usually arranged around the
pistil. The ovary of a pistil contains ovules.
When the eggs are fertilized, ovules
develop into seeds and the ovary becomes
a fruit.
Using Key Terms
1. In your own words, write a definition for each
of the following terms: xylem, phloem, stamen,
and pistil.
2. Use each of the following terms in a separate
sentence: sepal, petal, pistil, and ovary.
Understanding Key Ideas
11. Applying Concepts Pampas grass flowers are
found at the top of tall stems, are light-colored,
and are unscented. Explain how pampas grass
flowers are most likely pollinated.
Interpreting Graphics
Use the table below to answer the questions that
follow.
Age of Trees in a Small Forest
3. Which of the following flower structures produces pollen?
a. pistil
c. anther
b. filament
d. stigma
Number of trees
Number of growth rings
5
71
1
73
3
68
4. The
of a leaf allows carbon dioxide to enter.
a. stoma
c. palisade layer
b. epidermis
d. spongy layer
12. How many trees are older than 70 years?
5. Compare xylem and phloem.
13. What is the average age of these trees, in years?
6. Describe the internal structure of a leaf.
7. What are the functions of stems?
8. Identify the two types of stems, and briefly
describe them.
9. How do people use flowers?
Critical Thinking
10. Making Inferences Describe two kinds of root
systems. How does the structure of each system
help the roots perform their three functions?
Developed and maintained by the
National Science Teachers Association
For a variety of links related to this
chapter, go to www.scilinks.org
Topic: Structure of Seed Plants
SciLinks code: HSM1467
Answers to Section Review
1. Sample answer: Xylem transports
water and minerals. Phloem transports food
molecules. A stamen is the male reproductive part of a flower. A pistil is the female
reproductive structure of a flower.
2. Sample answer: A flower bud is protected by sepals. The petals of a flower
attract pollinators. The pistil of a flower is
often found at the center of the flower. The
ovary of a flower protects the ovules and
develops into a fruit.
3. c
4. a
CHAPTER RESOURCES
Chapter Resource File
CRF
• Section Quiz g
• Section Review g
• Vocabulary and Section Summary g
• Critical Thinking a
Technology
Transparencies
• L45 The Structure of a Flower
5. Sample answer: Xylem
transports water and nutrients
from the roots to the shoots.
Phloem transports food molecules throughout the plant.
6. Sample answer: A leaf
often has two middle layers.
The cells of the palisade layer
have many chloroplasts. The
spongy layer lies beneath the
palisade layer and includes the
xylem and phloem.
7. Sample answer: Stems
support the plant body, transport materials between the root
and shoot systems, and store
materials.
8. Herbaceous stems are soft,
thin, and flexible. Woody stems
are rigid and made of wood and
bark.
9. Sample answer: Flowers
are used for floral arrangements. Some flowers can be
eaten, used to make tea, or
used as spices. Flowers are
also used in perfumes, lotions,
and shampoos.
10. Sample answer: A taproot system has one main root, the taproot. Taproots may grow very
deep to reach water and minerals. They also hold the plant
in the soil. Taproots can also
store surplus food, as carrots
do. A fibrous root system has
several roots of a similar size
that spread out from the base
of the plant. Fibrous roots may
absorb water from the soil
surface. Fibrous roots spread
out from the stem and hold the
plant in place. They also store
some surplus food.
11. Sample answer: Pampas grass
flowers are pollinated by the
wind. They don’t have brightly
colored petals to attract pollinators, nor do they have a fragrance. Also, they are at the top
of a tall stem where they might
best catch the wind.
12. 6 trees
13. 5 ⫻ 71 ⫽ 355; 3 ⫻ 68 ⫽ 204;
355 ⫹ 204 ⫹ 73 ⫽ 632;
632 ⫼ 9 ⫽ 70.2 years
Section 4 • Structures of Seed Plants 321
Model- Making Lab
Model-Making Lab
Build a Flower
Teacher’s Notes
Build a Flower
OBJ ECTIVES
Time Required
One 45-minute class period
Build a model of a flower.
Lab Ratings
Explain how the model
represents an actual flower.
Describe the basic parts of a
flower.
r
Teacher Prep f
MATE RIALS
Student Set-Up f f
•
Concept Level f f
Clean Up f
•
•
•
MATER IAL S
The materials listed on the student
page include enough supplies for
one student or group of students.
•
•
art materials such as colored
paper, pipe cleaners, beads,
and yarn
card, index, 3 ⴛ 5 in.
glue
recycled items such as paper
plates and cups, yogurt
containers, wire, string,
buttons, cardboard, and bottles
scissors
tape
Scientists often make models in the laboratory. Models help
scientists understand processes and structures. Models are
especially useful when scientists are trying to understand processes that are too small to be seen easily, such as pollination,
or processes that are too large to be examined in a laboratory,
such as the growth of a tree. Models also make it possible to
examine the structures of objects, such as flowers.
In this activity, you will use your creativity and your understanding of the structure of a flower to make a model of a
flower from recycled materials and art supplies.
Procedure
1
Draw a flower similar to the one shown in the figure below.
This flower has both male and female parts. Not all flowers
have this structure. The flowers of many species of plants have
only male parts or only female parts, not both.
Petal
Stigma
SAFETY
Safety Caution
Anther
Remind students to review all
safety cautions and icons before
beginning this lab activity.
Filament
Style
Stamen
Ovary
Sepal
Pistil
2
Stem
Decide which materials you will use to represent each flower
part. Then, build a three-dimensional model of a flower that
looks like one of the flowers shown on the next page. The
model you build should contain each of the following parts:
stem, sepals, petals, stamens (anther and filament), and pistil
(stigma, style, and ovary).
CHAPTER RESOURCES
Holt Lab Generator CD-ROM
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Chapter 12 • Introduction to Plants
Jane Lemons
Western Rockingham
Middle School
Madison, North Carolina
• Leaf Me Alone!
• Travelin’ Seeds
Analyze the Results
3
After you build your model, draw a key for your
flower model on an index card. Label each of
the structures represented on your flower.
Analyze the Results
Lily
1
Organizing Data List the structures of a
flower, and explain the function of each part.
2
Identifying Patterns What is the outermost
part of your flower? the innermost part of your
flower?
3
Analyzing Data How are your flower model
and an actual flower alike? How are they
different?
Draw Conclusions
Tulip
4
Drawing Conclusions How might your flower
attract pollinators? What modifications could
you make to your flower to attract a greater
number of pollinators?
5
Evaluating Models Is your model an accurate
representation of a flower? Why or why not?
6
Making Predictions If you based your flower
model on a plant species that had flowers that
did not have both male and female parts, how
would that model be different from your current model?
Applying Your Data
Research flowering plants whose flowers do
not have both male and female reproductive
parts. Build models of the male flower and
the female flower for one of these flowering
plants. Then, compare the new models to your
original model, which includes both male and
female reproductive parts.
Hibiscus
CHAPTER RESOURCES
Workbooks
Whiz-Bang Demonstrations
• Inner Life of a Leaf a
EcoLabs & Field Activities
• The Case of the Ravenous Radish g
Long-Term Projects & Research Ideas
• Plant Planet a
Applying Your Data
Students should demonstrate an understanding of
how flowers with both male and female parts differ
from flowers with only male or only female parts.
Students’ models should reflect this understanding. Some students may also note that in some
species, both male and female flowers can be
found on one plant, but in other species, they
are found on different plants.
1. petal: the often colorful leafshaped part of a flower
that attracts pollinators
sepal: the modified leaves that
form the base of the flower and
that enclose and protect the bud
before the flower opens
stem: the main stalk of the
plant from which leaves,
flowers, and fruits develop;
water and nutrients move
through the stem between the
leaves and roots
pistil: the female reproductive
structure of a flower
stigma: the upper tip of the
pistil, which receives pollen
style: the stalklike part of the
pistil between the stigma and
ovary
ovary: the enlarged part of the
pistil in which ovules are formed
stamen: the male reproductive
structure of flowers
anther: the top of the stamen
that produces pollen
filament: the threadlike part of
the stamen that holds the anther
2. sepals; pistil
3. Sample answer: My flower
model and an actual flower have
the same parts: sepals, petals,
stamens, and pistils. Unlike real
flowers, my flower cannot be
pollinated, nor can it produce
seeds.
Draw Conclusions
4. Sample answer: My flower
will attract pollinators because
it has bright petals. I could give
my flower a fragrance to attract
more pollinators.
5. Sample answer: My flower
is accurate in appearance, but
it is not accurate in function. My
model looks like a flower, but it
cannot be pollinated or fertilized.
6. Sample answer: My flower
would have only stamen or only
pistils if it were modeled after a
plant that had flowers without
both male and female parts.
Chapter 12 • Chapter Lab 323
Assignment Guide
SECTION
1
5, 9, 11–12, 14, 19
2
3, 13
3
7
4
1–2, 4, 6, 8, 10, 16–18,
20, 22–25
1 and 4
21
2 and 3
15
pistil
vascular plant
xylem
pollen
nonvascular plant
1A
2
Using Key Terms
a. Plants and green algae may have a
common ancestor.
b. Green algae are plants.
rhizoid
rhizome
phloem
stamen
c. Plants and green algae have cuticles.
d. None of the above
0 In which part of a leaf does most
photosynthesis take place?
is the male part of a flower.
transports water and nutrients
through a plant.
.
new leaves and roots is called a
.
5A
does not have specialized tissues
for transporting water.
6
Understanding Key Ideas
transports food through a plant.
d. epidermis
q List four characteristics that all plants
w List the four main groups of plants.
e Name three nonvascular plants and
three seedless vascular plants.
r Why do scientists think green algae
and plants have a common ancestor?
t How are seedless plants, gymno-
UNDERSTANDING KEY IDEAS
7. a
8. d
9. a
10. a
11. Plants make their own food
by photosynthesis. Plants also
have cuticles. Plant cells have
rigid cell walls. Plants have a
two-stage life cycle.
12. nonvascular plants, seedless
vascular plants, gymnosperms,
and angiosperms
13. Mosses, liverworts, and hornworts are nonvascular plants.
Ferns, horsetails, and club
mosses are seedless vascular
plants.
c. xylem
b. phloem
share.
4 The male gametophytes of flowers are
contained in structures called
a. palisade layer
Short Answer
3 An underground stem that produces
stamen
Xylem
rhizome
pollen
nonvascular plant
Phloem
sperms, and angiosperms important to
the environment?
Multiple Choice
7 Which of the following statements
y What are two advantages that seeds
about angiosperms is NOT true?
have over spores?
a. Their seeds are protected by cones.
b. They produce seeds.
c. They provide animals with food.
d. They have flowers.
8 Roots
a. supply water and nutrients.
b. anchor and support a plant.
c. store surplus food.
d. All of the above
14. Sample answer: Plants and green algae
have many similarities, so scientists think
they are related. Both have the same kind
of chlorophyll and cell walls. Both store
food in the form of starch, and both have
a two-stage life cycle.
15. Sample answer: Nonvascular plants are
often the first plants to live in a new environment. They form a thin layer of soil, to
which seedless vascular plants add. Seedless plants also prevent soil erosion. Gymnosperms are often found in gardens and
parks, and angiosperms provide most of the
food that animals need to survive.
324
about plants and green algae is true?
Complete each of the following sentences by choosing the correct term
from the word bank.
ANSWERS
1.
2.
3.
4.
5.
6.
9 Which of the following statements
USING KEY TERMS
QUESTIONS
Chapter 12 • Introduction to Plants
16. Sample answer: When a young seed plant
begins to grow, it can use stored food in
the seed. Spores do not have stored food
to help a plant grow. Another advantage
is that seeds can be spread by animals,
while spores are spread by wind. Animals
spread seeds more efficiently than the wind
spreads spores.
Critical Thinking
17.
INTERPRETING GRAPHICS
s Look at the cross section of a woody
stem below. Use the diagram to determine the age of the tree.
CRITICAL THINKING
u Concept Mapping Use the following
terms to create a concept map:
flowers, pollen, stamens, ovaries, pistils,
stigmas, filaments, anthers, ovules,
petals, and sepals.
i Making Comparisons Imagine that a
seed and a spore are beginning to grow
in a deep, dark crack in a rock. Which
of the two is more likely to grow into
an adult plant? Explain your answer.
Use the diagram of the flower below to
answer the questions that follow.
a
d
o Identifying Relationships Grass flowers
do not have strong fragrances or bright
colors. How might these characteristics
be related to the way by which grass
flowers are pollinated?
p Analyzing Ideas Plants that are pol-
linated by wind produce more pollen
than plants pollinated by animals do.
Why might wind-pollinated plants
produce more pollen?
a Applying Concepts A scientist dis-
covered a new plant. The plant has
vascular tissue and produces seeds.
It has brightly colored and strongly
scented flowers. It also has sweet fruits.
Based on this information, which of
the four main types of plants did the
scientist discover? How is the plant
most likely pollinated? How does the
plant most likely spread its seeds?
c
b
d Which letter corresponds to the structure in which pollen is produced?
What is the name of this structure?
f Which letter corresponds to the struc-
ture that contains the ovules? What is
the name of this structure?
g Which letter corresponds to the structure that protects the flower bud?
What is the name of this structure?
An answer to this
exercise can be
found at the end
of this book.
18. Sample answer: The seed is
more likely to grow than the
spore. Because spores do not
have stored food, the new plant
must begin photosynthesis right
away. But the spore and seed
are in a deep, dark crack, so
the spore is not getting any light
for photosynthesis. Because
the seed has stored food, the
plant can grow in the crack
without light for photosynthesis.
19. Sample answer: If grass
flowers had bright petals and
strong fragrances, they would
likely be pollinated by animals.
However, because grass flowers do not have these characteristics, they are most likely
pollinated by the wind.
20. Sample answer: Animals pollinate plants by travelling from
one plant to another. However,
the wind may not blow from
one plant to another, so windpollinated plants produce more
pollen. Producing more pollen
increases the chance that
pollen will be blown onto the
female structures of windpollinated plants’ flowers.
21. Sample answer: The plant is
an angiosperm because it has
flowers and fruit. Because the
plant has brightly colored and
strongly scented flowers, it is
likely pollinated by animals.
The fruits are sweet, so they
are likely eaten by animals, and
the seeds are dispersed elsewhere by the animals.
CHAPTER RESOURCES
Chapter Resource File
CRF
• Chapter Review g
• Chapter Test A g
• Chapter Test B a
• Chapter Test C s
• Vocabulary Activity g
Interpreting Graphics
22. 10 years
23. d; anther
24. b; ovary
25. c; sepal
Workbooks
Study Guide
• Study Guide is also available in Spanish.
Chapter 12 • Chapter Review 325
Teacher’s Note
To provide practice under more
realistic testing conditions, give
students 20 minutes to answer
all of the questions in this
Standardized Test Preparation.
READI NG
Read each of the passages below. Then, answer the questions
that follow each passage.
MISCONCEPTION
ALERT
Answers to the standardized
test preparation can help you
identify student misconceptions and misunderstandings.
READING
Passage 1
1. B
2. H
3. B
Question 2: Some students may
think the word species refers to DNA
or genes because members of a species share similar genes and DNA.
However, this fact is not in the passage. As the word species is used in
the passage, it can only mean “group
of organisms.”
Question 3: Some students may
select answer D, but the two items in
this answer are part of a single process, not two. Bacteria and a gene gun
are the two distinct means of introducing new DNA discussed in the
passage. Fungi are not mentioned in
the passage.
326
Passage 1 Through genetic engineering, scientists are now able to duplicate one organism’s DNA
and place a certain gene from the DNA into the
cells of another species of plant or animal. This
technology enables scientists to give plants and
animals a new trait that can then be passed on
to future generations. There are two methods
to introduce new DNA into plant cells. In one
method, DNA is first placed inside a special bacterium, which carries the DNA into the plant cell. In
the second method, microscopic particles of metal
are coated with the new DNA and fired into the
plant cells with a device called a gene gun.
Passage 2 The main function of leaves is photosynthesis, or the production of food. However,
some leaves have functions other than photosynthesis. For example, the leaves on a cactus plant
are modified as spines. These spines discourage
animals from eating the cactus. The leaves of
another plant, the sundew, are modified to catch
insects. Sundews live in areas with nitrogen-poor
soil. They don’t get enough nitrogen from the
soil to meet their needs. So, the plants use their
modified leaves to catch insects. Then, the sundews digest the insects to get the nitrogen they
need to survive.
1. Based on the passage, what does genetic
engineering allow scientists to do?
A to breed better plants
B to move genes from one organism to
another
C to see a very small object without a
microscope
D to grow plants without soil
1. Based on the passage, which of the following
statements about photosynthesis is true?
A Photosynthesis produces modified leaves.
B Photosynthesis is how plants catch insects
for food.
C Photosynthesis discourages animals from
eating plants.
D Photosynthesis is how plants get food.
2. In the passage, what does the word species most
likely mean?
F DNA
G future generations
H group of organisms
I genes
2. Based on the passage, what do the modified
leaves of cactuses do?
F They discourage animals from eating them.
G They catch insects for nitrogen.
H They function mainly for photosynthesis.
I They help cactuses get enough nitrogen
from the soil.
3. Based on the passage, what are the two most
common ways genes are moved to plant cells?
A by bacteria and fungi
B by bacteria and a gene gun
C by fungi and a gene gun
D by particles of metal and a gene gun
Passage 2
1. D
2. F
3. A
Chapter 12 • Introduction to Plants
3. Based on the passage, what can be concluded
about pitcher plants if they capture insects?
A They grow in areas with nitrogen-poor soil.
B They are trying to discourage animals from
eating them.
C They don’t need nitrogen from insects to
survive.
D They have leaves that are modified as
spines.
Question 2: Some students may think that
the modified leaves of cactuses catch insects,
function for photosynthesis, or help the plants get
enough nitrogen. Although all of these things are
mentioned in the passage, the spines of cactuses
are not designed to catch insects, nor do they contain chlorophyll for photosynthesis. In the passage,
sundews need nitrogen from insects, but cactuses
are not described as needing nitrogen from
insects.
I NTE RPRETI NG G RAPH ICS
The pie graph below shows the distribution of four types of plants. Use the pie
graph below to answer the questions that
follow.
Distribution of Plants
Angiosperms
Gymnosperms
INTERPRETING GRAPHICS
MATH
Mosses and
their relatives
Ferns and
their relatives
1. Which of the following types of plants is the
least common?
A ferns and their relatives
B mosses and their relatives
C angiosperms
D gymnosperms
3. About what percentage of plants are mosses,
ferns, and their relatives?
A 1%
B 10%
C 20%
D 80%
4. If there are about 265,000 species of plants,
about how many of the species are mosses and
relatives of mosses?
F 2,650 species
G 13,250 species
H 26,500 species
I 212,000 species
1. Sophie wants to plant a garden. Her garden is
25 m wide. She puts a row of plants every half
meter. Every fifth row is a row of flowers. If
the rest of the rows are vegetables, about how
many rows of vegetables are in the garden?
A 10 rows
B 25 rows
C 40 rows
D 50 rows
Question 3: Some students may
think that the answer to this question
is 10%. However, the question asks for
both mosses and their relatives and
ferns and their relatives. Together,
these two groups comprise about 20%
of plants.
2. The area of a garden is 50 m2. If the garden is
12 m long, which of the following equations
expresses the value of w, the width of the
garden?
F w ⫽ 12 ⫻ 50
G w ⫽ 50 ⫻ 12
H w ⫽ 50 ⫼ 12
I w ⫽ 12 ⫼ 12
3. There are 140 species of cycads. If 18% of
gymnosperms are cycads, about how many
gymnosperms are there?
A 25 gymnosperms
B 165 gymnosperms
C 775 gymnosperms
D 2,520 gymnosperms
4. A packet of cabbage seeds that contains
enough seeds for two rows costs $2.00. A
packet of carrots that contains enough seeds
for three rows costs $2.25. If Katy wants to
plant five rows of cabbage and seven rows of
carrots, how much will the seeds cost?
F $12.75
G $12.00
H $8.50
I $6.00
MATH
1. C
2. H
3. C
4. F
Standardized Test Preparation
2. About what percentage of plants are
angiosperms?
F 1%
G 10%
H 20%
I 80%
1. D
2. I
3. C
4. H
Read each question below, and choose the
best answer.
CHAPTER RESOURCES
Chapter Resource File
CRF
• Standardized Test Preparation g
State Resources
Question 1: Some students may
answer 50 rows if they don’t notice
that every fifth row in the garden is
flowers. Other students may answer
10 rows if they calculate the number
of rows of flowers instead of the rows
of vegetables. Some students may
answer 25 rows because the number
25 appears in the question. However,
40 rows is the best answer. You may
want to diagram this problem on the
board to help students understand it.
Question 3: Some students may
answer 25 gymnosperms if they calculate 18% of 140. Other students will
answer 165 gymnosperms if they multiply 140 by 1.18. Some students will
answer 2,520 if they multiply 140 by 18.
However, to find the total number of
gymnosperms, students should divide
140 by 0.18, which yields 778. So, the
best answer is 775 gymnosperms.
For specific resources for your state,
visit go.hrw.com and type in the
keyword HSMSTR.
Chapter 12 • Standardized Test Preparation 327
in Action
in Action
Scientific Debate
Background
The risks of taking herbal supplements can increase when
supplements contain more than
one ingredient. Steve Bechler, a
23-year-old minor-league baseball player, was a regular user of
a weight-loss dietary supplement
containing ephedra and caffeine.
During spring training with
the Baltimore Orioles in 2003,
Bechler collapsed and died. After
his death, minor league baseball
joined professional and college
football in banning ephedra use
by its athletes.
Science, Technology,
and Society
v------------------------------------- GENERAL
Have students research plant
poaching in your area. Have
them identify which plants are
being stolen and why, and have
them identify steps being taken
to control poaching. Ask students to contact local park
managers or state and federal
natural resources agencies, such
as the National Park Service.
Other sources of information
include the Internet, newspapers, and magazines. Students
should makes posters about
their findings, including pictures
of the plants that poachers steal
and a description of the plants’
habitats.
328
Science, Technology,
and Society
Plant Poachers
Humans have always used plants for food,
for shelter, or for medicine. In fact, one of
our most common medicines, aspirin, is
similar to a chemical found in the bark of
a willow tree. Today, many people still use
natural plant products, such as pills or teas,
as medicine. These products are often called
herbal supplements. Echinacea, St. John’s
wort, and ma huang are just a few examples
of the herbal supplements that people use
to treat a variety of health problems. People
spend billions of dollars on herbal supplements each year. But are herbal supplements
safe to use?
Social Studies
Make a poster illustrating a plant used for
medicine by native cultures and the health
problems the plant is used to treat.
Imagine you’re walking through a swamp.
The swamp is full of life. You’re surrounded
by trees, vines, and water lilies. You can hear
frogs singing and mosquitoes buzzing. Then,
you notice a ghost orchid hanging from a
tree branch. The flower of this orchid looks
like a ghost or like a white frog leaping. For
some people, this orchid is worth stealing.
These people, called plant poachers, steal
orchids and other plants from the wild.
Many plant species and natural areas are
threatened by plant theft.
Math
A plant poacher stole 100 plants from a
nature preserve. He planned on selling each
plant for $50, but he was caught and was
fined $300 for each plant he stole. What is
the difference between the total fine and the
total amount of money the plant poacher
planned on selling the plants for?
Answer to Social Studies Activity
Answer to Math Activity
Students should demonstrate an understanding
of the medicinal uses of plants by native cultures in places such as South America and Asia.
Students may also research traditional plant use
by Native Americans from North America and
by ancient Europeans. Posters should include
comprehensive information about the plant, how
it is used, and what it is used to treat. Some students may also include information about the
effectiveness of the plant.
$25,000 (100 ⫻ $50 ⫽ $5,000; 100 ⫻ $300 ⫽
$30,000; $30,000 ⫺ $5,000 ⫽ $25,000)
Chapter 12 • Introduction to Plants
Careers
Background
Paul Cox
Some biologists estimate that
there are 235,000 species of
flowering plants in the world.
Of these, less than half of 1%
have been studied for their
potential medicinal qualities.
Because there are so many species, efficient strategies are necessary to find the plants most
likely to have medicinal value.
One strategy used by ethnobotanists is to assume that if native
people use a local plant for medicine, then the plant probably
has some medicinal value.
Many ethnobotanists seek out
native healers or shamans. Ethnobotanists hope to acquire the
knowledge that has taken the
shamans years to accumulate.
With these insights, the
researchers can then decide
which plants they should
collect and study.
Ethnobotanist Paul Cox is an ethnobotanist. He travels to remote places to look
for plants that can help treat diseases. He seeks the advice of native healers in his
search. In Samoan cultures, the healer is one of the most valued members of the
community. In 1984, Cox met a 78-year-old Samoan healer named Epenesa. Epenesa
understood human anatomy, and she dispensed medicines with great accuracy.
After Cox spent months observing
Epenesa, she gave him her treatment for
yellow fever. Cox brought the yellow-fever
remedy to the United States. In 1986,
researchers at the National Cancer Institute
found that the plant contains a virus-fighting chemical called prostratin, which may
have potential as a treatment for AIDS.
When two of the Samoan healers that
Cox observed died in 1993, generations of
medical knowledge was lost with them.
The healers’ deaths show the urgency
of recording this knowledge before all
of the healers are gone. Cox and other
ethnobotanists work hard to gather
knowledge from healers before their
knowledge is lost.
Language Arts
Imagine that you are a healer.
Write a letter to an ethnobotanist
describing some of the plants you use to
treat diseases.
WRITING
SKILL
Some of the most useful drugs
developed from plants used
by indigenous peoples include
aspirin, for reducing pain and
inflammation; codeine, for
decreasing pain and suppressing
coughs; and quinine, for combating malaria.
To learn more about these
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keyword HL5PL1F.
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articles related to this chapter
by visiting go.hrw.com. Just
type in the keyword HL5CS12.
Answer to Language Arts Activity
In their letters, students should demonstrate
an understanding of how important native healers are to ethnobotanists. Students should also
demonstrate an understanding of the fact that
although native cultures may seem primitive,
the knowledge that many native healers have is
actually very sophisticated. In some cases, this
knowledge may rival that of modern medicine.
Chapter 12 • Science in Action 329