Download Introduction to Plants

CHAPTER
23
Introduction
to Plants
Quick Review
Answer the following without referring to
earlier sections of your book.
1. Describe the process of mitosis. (Chapter 6,
Section 3)
6E
2. Describe the process of meiosis. (Chapter 7,
Section 1)
6E
3. Identify life cycles that have a gametophyte
and life cycles that have a sporophyte.
(Chapter 7, Section 2)
13B
4. Describe the role of mycorrhizae. (Chapter 12,
Section 3 and Chapter 22, Section 3.)
5. List the characteristics of the kingdom Plantae.
(Chapter 19, Section 3)
8C TAKS 2
Did you have difficulty? For help, review the
sections indicated.
Reading Activity
Before you begin to read this chapter, survey
each section and identify any subtitles, headings,
and captions that signal the topic of discussion.
As you read, locate other words in the body of
the text that signal the sequential pattern.
Looking Ahead
Show students pictures or live
specimens of several plants from
different phyla. Ask students to
point out the similarities and differences between the groups of plants.
On the board or overhead projector,
develop a chart organizing the
characteristics that students
point out.
Quick Review
Answers
Section 1
Adaptations of Plants
Establishment of Plants on Land
Vascular Tissue, Seeds, and Flowers
Plant Life Cycles
Section 2
Kinds of Plants
Nonvascular Plants
Seedless Vascular Plants
Gymnosperms
Angiosperms
Section 3
Plants in Our Lives
Plants as Food
Cereals
Nonfood Uses of Plants
www.scilinks.org
National Science Teachers Association sci LINKS Internet
resources are located throughout this chapter.
Plants provide us with the food and oxygen that
make life possible. They enrich our lives with beauty
and sweet scents. Plants also provide buildings, paper,
furniture, clothing, and medicines.
Opening Activity
501
Bio 3D Describe the connection between biology and
Bio 8A Collect and classify organisms at several taxo-
future careers.
Bio 3F Research and describe the history of biology and
contributions of scientists.
Bio 5A Compare cells from different parts of plants and
animals including roots, stems, leaves, epithelia,
muscles, and bones to show specialization of structure and function.
Bio 6E Compare the processes of mitosis and meiosis
and their significance to sexual and asexual
reproduction.
nomic levels such as species, phylum, and kingdom
using dichotomous keys.
Bio 10C Analyze and identify characteristics of plant
systems and subsystems.
Bio 11C Analyze the importance of nutrition, environmental conditions, and physical exercise on health
Bio 13B Survey and identify methods of reproduction,
growth, and development of various types of plants.
1. During mitosis, chromosomes
line up along the equator of the
dividing cell and the chromatids
are pulled apart, with matching
chromosomes going to each
new cell. Bio 6E
2. In meiosis, a single cell undergoes two divisions to produce
four gamete cells, each with
only one set of chromosomes.
During the first division of
meiosis, homologous chromosome pairs line up side-by-side
at the equator. These pairs are
separated in the first division.
The rest of the process is like
mitosis. Bio 6E
3. Plants, algae, and some protists
have life cycles with a diploid
phase called the sporophyte
and a haploid phase called
the gametophyte. Bio 13B
4. Mycorrhizae obtain mineral
nutrients from the soil that are
used by the plant, and the plant
provides carbohydrates that
are used by the mycorrhizae.
5. Plants are photosynthetic organisms with vascular tissue. Plant
cells have walls containing cellulose. Individual plants cannot
move from place to place. Plants
are the primary producers in
terrestrial ecosystems.
TAKS 2 Bio 8C
Reading Activity
Answers
Answers will vary but should
include general characteristics
shared by all plants, the unique
features of different groups of
plants, and the many ways that
humans use plants.
Chapter 23 • Introduction to Plants
501
Section 1
Section 1
Adaptations of Plants
Focus
Establishment of Plants on Land
Objectives
Overview
Before beginning this section
review with your students the
objectives listed in the Student
Edition. This section introduces
the adaptations that plants have
made to life on land. Students
will learn how groups of plants
become increasingly well suited for
dryer conditions. They will learn
the common characteristics of all
plants, as well as the characteristics
that differentiate vascular from
nonvascular plants.
Bellringer
Ask students to write three things
that are important for the survival
of an organism on land. (Students
should recognize the need for obtaining water and nutrients, the need for
maintaining homeostasis in a dry,
sunny environment, and the need for
reproduction out of water.) Bio 11C
Plants are the dominant group of organisms on land, based on
weight. The kingdom Plantae is a very diverse group. Individuals
range from less than 2 mm across to more than 100 m tall. Most
plants are photosynthetic; they produce organic materials from
● Distinguish nonvascular
inorganic materials by photosynthesis. A few plant species, like
plants from vascular
the one shown in Figure 1, live as parasites. Many parasitic plants
13A TAKS 3
plants.
cannot photosynthesize.
● Relate the success of
Plants probably evolved from multicellular aquatic green algae
plants on land to seeds
and flowers.
7A 13A TAKS 3 that could not survive on land. Multicellularity enabled plants to
develop features that helped them live more successfully on land.
● Describe the basic strucBefore plants could thrive on land, they had to be able to do three
ture of a vascular plant
things: absorb nutrients from their surroundings, prevent their bod13A TAKS 3
sporophyte.
ies from drying out, and reproduce without water to transmit sperm.
● Summarize how plants
are adapted to living on
land.
7A 13A TAKS 3
Key Terms
Absorbing Nutrients
cuticle
stoma
guard cell
vascular system
nonvascular plant
vascular plant
seed
embryo
seed plant
flower
phloem
xylem
shoot
root
meristem
Aquatic algae and plants take nutrients from the water around
them. On land, most plants take nutrients from the soil with their
roots. Although the first plants had no roots, fossils show that
fungi lived on or within the underground parts of many early
plants. So botanists think that fungi may have helped early land
plants to get nutrients from Earth’s rocky surface. Symbiotic relationships between fungi and the roots of plants are called mycorrhizae. Today, about 80 percent of all plant species form
mycorrhizae.
Preventing Water Loss
The first plants lived at the edges of bodies of water, where drying
out was not a problem. A watertight covering, which reduces water
loss, made it possible for plants to
live in drier habitats. This covering,
called the cuticle, is a waxy layer
that covers the nonwoody aboveground parts of most plants. But like
the wax on a shiny car, the cuticle
does not let oxygen or carbon dioxide pass through it. Pores called
stomata (STOH muh tuh) (singular,
stoma) permit plants to exchange
oxygen and carbon dioxide. Stomata,
which extend through the cuticle
and the outer layer of cells, are
found on at least some parts of most
Figure 1 Rafflesia. The
flowers of Rafflesia keithii, of
Malaysia, measure almost 1 m
across and weigh up to 11 kg
(24 lb). The plant, which has no
stems or leaves, is parasitic on
the roots of grape vines.
502
Chapter Resource File
pp. 502–503
Student Edition
TAKS Obj 1 Bio/IPC 2B, 2C
TAKS Obj 2 Bio 8C
TAKS Obj 3 Bio 7A
TAKS Obj 3 Bio 7B
TAKS Obj 3 Bio 12B
TAKS Obj 3 Bio 13A
TEKS Bio 5A, 7A, 7B, 8C, 12B, 13A
TEKS Bio/IPC 2B, 2C
Teacher Edition
TAKS Obj 1 Bio/IPC 2B, 2C
TEKS Bio 5A, 10C, 11C
TEKS Bio/IPC 2C
502
• Lesson Plan GENERAL
• Directed Reading
• Active Reading GENERAL
• Datasheet for Quick Lab
GENERAL
Transparencies
TT Bellringer
TT Stomata and Guard Cells
Chapter 23 • Introduction to Plants
Planner CD-ROM
• Reading Organizers
• Reading Strategies
• Occupational Application Worksheet
Botanist GENERAL
Figure 2 Stomata and guard cells
The surface of a leaf has numerous stomata, each of which is surrounded
by a pair of guard cells.
Teach
Guard cells
Using the Figure
GENERAL
Draw students’ attention to
Figure 2. Point out the guard cells
and the stoma of the leaf. Be sure
students understand that the guard
cells form the opening that is called
a stoma. Tell students that in many
species, the majority of stomata are
on the lower leaf surfaces. Ask students how this benefits plants. (The
lower surface is usually not exposed
to direct sunlight. This helps reduce
water loss.) Bio 5A, 10C
Stoma
Spiderwort leaves
plants. A pair of specialized cells called guard cells border each
stoma, as seen in Figure 2. Stomata open and close as the guard cells
change shape.
Reproducing on Land
SKILL
Aquatic algae reproduce sexually when sperm swim through the
water and fertilize eggs. The sperm of most plants, however, must be
able to move without water. In most plants, sperm are enclosed in a
structure that keeps them from drying out. The structures that contain sperm make up pollen. Pollen permits the sperm of most plants
to be carried by wind or animals rather than by water.
Vocabulary Have students use a
dictionary to find the origin of the
term stoma. (Stoma comes from
the Greek word
English Language
Learners
meaning “mouth.”)
Observing the Behavior
of Stomata 2B 2C 5A TAKS 1
Observing the
Behavior of Stomata
You can use nail polish to see that a leaf has many stomata.
TAKS 1 Bio/IPC 2B, 2C; Bio 5A, 10C
Skills Acquired
Analyzing results,
making comparisons,
drawing conclusions
Materials
clear nail polish, plant kept in light, plant kept in darkness,
two 4–5 cm strips of clear tape, 2 microscope slides,
compound microscope
Procedure
1.
Paint a thin layer
of clear nail
polish on a 1 ⫻ 1 cm area of
a leaf on a plant kept in light.
Do the same using a plant
kept in darkness. Let the nail
polish dry for 5 minutes.
2. Place a 4–5 cm strip of clear
tape over the nail polish on
each leaf. Press the tape
firmly to the nail polish.
3.
Carefully pull the tape
off each leaf. Stick
each piece of tape to a
microscope slide. Label it
appropriately.
4. View each slide with a microscope, first under low power
and then under high power.
Analysis
1. Describe any differences in
the stomata of the two plants.
2. Critical Thinking
Drawing Conclusions
Which plant will lose water
more quickly? Explain.
5. Draw and label what you see
on each slide.
503
IPC Benchmark Mini-Lesson
Biology/IPC Skills TAKS 1 Bio/IPC 2C
Organize, analyze, evaluate ... data.
Activity Have students create a dichotomous key
for identifying the different types of plants found in
this chapter.
BUILDER
did you know?
Pine Stomata Pine trees often have sunken
stomata. This adaptation helps them conserve
water, an important ability for plants growing
in cold climates. Many pine trees grow where
the soil freezes and the winds are dry. Bio 5A, 10C
Teacher’s Notes
Instruct students to put the
nail polish on the lower leaf
surface because there will likely
be more stomata there. Tell
students that the nail polish is
used to make an impression of
the leaf surface and may also
remove some of the cells on the
leaf’s surface.
Answers to Analysis
1. The students should note that
the plant kept in the light has
more open stomata.
2. The plant kept in the light will
lose water more quickly
because it has more open
stomata. While this seems inefficient for for preventing water
loss, the stomata must be open
during the day to allow photosynthesis to occur.
Chapter 23 • Introduction to Plants
503
Vascular Tissue, Seeds, and Flowers
Teach
Teaching Tip
GENERAL
www.scilinks.org
Topic: Vascular Plants
Keyword: HX4182
Tall Tendencies Ask students to
brainstorm and suggest characteristics that would enable plants to
grow tall. (a vascular system to carry
water and nutrients; rigid cell walls
to provide support; thickened stems)
Ask students to speculate on the
advantages of increased plant height.
(Tall plants are able to obtain more
sunlight due to reduced competition
and shade. Tall plants are also able to
send their pollen and fruit/seeds over
greater distances than shorter plants.)
Advantages of Conducting Tissue
The first plants were small. Materials were transported within their
bodies by osmosis and diffusion. Today, most plants have strands of
specialized cells that transport materials. These specialized cells are
connected end to end like the sections in a pipeline, as shown in
Figure 3. Some strands carry water and mineral nutrients from the
roots to the leaves. Other strands carry organic nutrients from the
leaves to wherever they are needed.
Specialized cells that transport water and other materials within a
plant are found in vascular tissues. The existence of vascular tissue
allowed for larger and more-complex plants. The larger, morecomplex plants have a vascular system, a system of well-developed
vascular tissues that distribute materials more efficiently. Three
groups of plants alive today lack a vascular system. These relatively
small plants that have no vascular system are called nonvascular
plants. Plants that have a vascular system are called vascular plants.
LS Intrapersonal Co-op Learning
TAKS 3 Bio 13A, 13B; Bio 5A, 10C
Activity
GENERAL
Seed Dispersal Bring a variety of
fruits and cones containing seeds
to class. Include some large colorful
fruits (apples, oranges, grapes);
some small fruits with wings (elm,
maple) or umbrella-like appendages
(dandelion); some cones with scales
(pine, spruce, fir); and a coconut.
Ask students to examine the fruits
and cones and identify which of
the fruits are dispersed by the wind.
(winged fruits or small fruits with
appendages, conifer seeds) Ask
students which seeds are likely
dispersed by animals. (showy, fleshy
fruits) Ask students how the coconut
is dispersed. (By water, since the
coconut can float along coasts and
from island to island.) LS Visual
As plants adapted to land, they developed many features that helped
in their success. There was no basic difference in structure between
the aboveground and underground parts of the earliest plants. Later
plants, however, had roots, stems, and leaves. One of the most important changes in plants was the development of conducting tissues
that move water and other materials through the plant body.
Advantages of Seeds
After vascular tissue, the seed was the next important adaptation to
appear in plants. A seed is a structure that contains the embryo of
a plant. An embryo is an early stage in the development of plants
and animals. Most plants living today are seed plants —vascular
plants that produce seeds. The first seed plants appeared about 380
million years ago. Seeds offer a plant’s offspring several survival
advantages, which are summarized in Figure 4.
Figure 3 Vascular tissue.
Thick-walled, tubular cells
like these carry water from the
tips of roots to the tips of
leaves. Stacked end to end,
these cells form tiny pipes
called vessels.
TAKS 2 Bio 8C; TAKS 3 Bio 13A
Transparencies
TT Vascular Tissue
TT Structure of a Vascular Plant
TT Structure and Function of Seeds
pp. 504–505
Student Edition
TAKS Obj 2 Bio 8C
TAKS Obj 3 Bio 7B
TAKS Obj 3 Bio 13A
TEKS Bio 7B, 8C, 13A
Teacher Edition
TAKS Obj 2 Bio 8C
TAKS Obj 3 Bio 7A, 13A
TEKS Bio 5A, 7A, 8C, 10C, 13A, 13B
504
504
EARTH SCIENCE
CONNECTION
Students may be surprised to learn that the
tallest trees on Earth are in California. They
are the coast redwoods (Sequoia sempevirens),
which can grow more than 110 m (360 ft).
The tallest flowering plant is the Australian
eucalyptus (Eucalyptus regnans), which has
been measured at 84 m (275 ft). The next
tallest tree is the giant sequoia (Sequiadendron
giganteum) of California, which can reach
76 m (250 ft). TAKS 2 Bio 8C
Chapter 23 • Introduction to Plants
The seedless vascular plants were the most
common plants on Earth about 300 million
years ago. Many of these were very large trees,
including a number of different tree ferns.
When these plants died, their bodies became
buried and only partly decomposed. The
remains of their tissues formed underground
coal deposits. People have dug up many of
these carbon-rich deposits and burned the coal
as a fossil fuel. The period of time in Earth’s
history when these plants were most abundant is called the Carboniferous period.
Figure 4 Structure and function of seeds
The structure of a seed helps it to perform its functions.
Pine
seedling
Teaching Tip
Stored food
Wing
Pine
cone
Pine
seed
Seed coat
Embryo
Seeds
The seed coat of a pine seed
covers and protects the embryo.
The stored food supply will nourish
the embryo as it starts to grow.
A wing helps pine
seeds disperse.
1. Protection. Seeds are surrounded by a protective cover called
the seed coat. The seed coat protects the embryo from drying
out and from mechanical injury and disease.
2. Nourishment. Most kinds of seeds have a supply of nutrients
stored in them. These nutrients are a ready source of nourishment for a plant embryo as it starts to grow.
Pine seeds may not germinate for several years.
www.scilinks.org
Topic: Structure and
Function of Seeds
Keyword: HX4169
TAKS 2 Bio 8C; TAKS 3 Bio 13A; Bio 13B
Group Activity
3. Plant dispersal. Seeds disperse (spread) the offspring of seed
plants. Many seeds have structures that help wind, water, or animals carry them away from their parent plant. Dispersal
prevents competition for water, nutrients, light, and living space
between parents and offspring.
4. Delayed growth. The embryo in a seed is in a state of
suspended animation. Most seeds will not sprout until conditions are favorable, such as when moisture is present and the
weather is warm. Thus, seeds make it possible for plant
embryos to survive through unfavorable periods such as
droughts or cold winters.
Advantages of Flowers
The last important adaptation to appear as plants evolved was the
flower, a reproductive structure that produces pollen and seeds.
Flowers make plant reproduction more efficient. The pollen of the first
seed plants was carried by wind. Large amounts of pollen are needed
to ensure cross-pollination by wind—an inefficient system. Most
plants living today are flowering plants—seed plants that produce
flowers. The first flowering plants appeared more than 130 million
years ago. Many flowers attract animals, such as insects, bats, and
birds. As Figure 5 shows, tiny pollen grains stick to animals, which
carry pollen directly from one flower to another. Flowering plants that
are pollinated by animals produce less pollen, and cross-pollination
can occur between individuals that live far apart.
GENERAL
Durability of Seeds Tell students
that seeds are adapted for survival
in a wide variety of climates.
Emphasize that seeds can survive
in a dormant state if conditions
are unfavorable for growth. Have
students speculate about why so
many seedlings appear after forest
fires. (Fire clears the accumulated leaf
litter on the forest floor. Many seeds
need contact with bare mineral soil to
germinate. Fire also opens some cones
to allow seeds to fall out and germinate. Fire may also eliminate shade,
allowing light to reach the forest floor
and stimulate germination.)
Figure 5 Pollination. This
honeybee is covered with
pollen grains containing the
sperm of the plant it has just
visited. The bee will transfer
some of the pollen to the next
flower it visits.
Observing Pollen Grain Have
students work in groups of two or
three. Have students make wetmount slides of pollen from pine
trees or observe prepared slides of
pine pollen. Then have them draw
and label the pollen grains and
estimate their size based on the
field of view. If possible, have
students compare the pollen from
several different species. Then have
students examine the pollen from
angiosperms, and compare the
pollen structure of different groups.
If pollen is not in season, use
prepared slides or pollen from
nursery grown flowers. Have
groups prepare posters of the
different pollen structures.
LS Visual TAKS 2 Bio 8C; Bio 13B
505
IPC Benchmark Review
To prepare students for the TAKS and accompany
the discussion of stomata, have students review
Response to Pressure and Temperature TAKS 4
IPC 7A on p. 1049 of the IPC Refresher in the Texas
Assessment Appendix of this book.
did you know?
Attractive Orchids Orchids have highly
elaborate ways of attracting pollinators. One
orchid species has a flower that resembles a
female wasp. Male wasps pick up some pollen
while trying to mate with the modified petals.
In another species, the flower holds a small
pool of water. When a bee tries to collect nectar, it falls into the water and can escape only
through a narrow passageway that forces the
bee to brush against the pollen-bearing anthers.
TAKS 3 Bio 7A (grade 11 only); Bio 13B
Chapter 23 • Introduction to Plants
505
Plant Life Cycles
Teach, continued
continued
Teaching Tip
Life Cycle Review Ask students
the following questions: How do
scientists represent the chromosome
number of a gametophyte? (n, or
haploid) How do scientists denote
the chromosome number of the
sporophyte? (2n, or diploid) What
is the name of the first sporophyte
cell? (zygote) What process produces
a zygote? (fertilization) What is the
name of the first gametophyte cell?
(spore) What process produces
spores? (meiosis)
TAKS 2 Bio 8C; Bio 6E, 13B
Using the Figure
GENERAL
Draw students’ attention to
Figure 7. Have students compare
the relative sizes of sporophytes
and gametophytes in the moss and
the flowering plant. (Students should
notice that the moss sporophyte is
smaller than the gametophyte, while
the flowering-plant gametophyte is
considerably smaller than the
flowering-plant sporophyte.)
In many algae, the zygote is the only diploid (2n) cell. It undergoes
meiosis right after fertilization. So the bodies of these algae consist
of haploid cells. In the ancestors of plants, however, meiosis was
delayed. The zygote divided by mitosis and grew into a multicelled
sporophyte that was diploid and produced haploid (n) spores by
Figure 6 Alternation of
meiosis. The spores grew into multicelled gametophytes that were
generations. In the life cycle
haploid and produced gametes by mitosis. As a result, plants have
of a plant, a diploid sporophyte
life cycles in which haploid plants that make gametes (gametogeneration alternates with
a haploid gametophyte
phytes) alternate with diploid plants that make
generation.
spores (sporophytes). A life cycle in which a gametophyte alternates with a sporophyte is called alterDiploid (2n)
Haploid (n)
nation of generations. The basic plant life cycle is
shown in Figure 6.
n
Spore-forming cell
Unlike the green algae with alternation of generan Spores
Meiosis
tions,
plants have gametophytes and sporophytes
n
2n
that
look
very different. In addition, the relative
n
sizes of gametophytes and sporophytes changed as
plants evolved, as Figure 7 shows. In nonvascular
2n
n
n
plants, such as mosses, the gametophyte generation
Sporophyte
Gametophytes
is dominant (most noticeable). In vascular plants,
such as the flowering plants, the sporophyte genMitosis
eration is dominant. Like the presence of a vascular
2n
system, the relative sizes of gametophytes and
n
Zygote
sporophytes is a fundamental difference between
n
Fertilization
Gametes
the nonvascular plants and the vascular plants.
Figure 7 Nonvascular plants versus vascular plants
Gametophytes and sporophytes vary greatly in size.
The gametophytes
form inside a flower.
LS Visual Bio 13B
Sphagnum moss
A sporophyte grows
atop a gametophyte.
C24 000 007b
506
REAL WORLD
CONNECTION
pp. 506–507
Student Edition
TAKS Obj 2 Bio 8C
TAKS Obj 3 Bio 7A
TAKS Obj 3 Bio 7B
TAKS Obj 3 Bio 13A
TEKS Bio 7A, 7B, 8C, 13A
Teacher Edition
TAKS Obj 2 Bio 8C
TAKS Obj 3 Bio 13A
TEKS Bio 6E, 7A, 7B, 8C, 13A, 13B
506
Pollen allergies are commonly known as
“hay fever.” Such allergies are actually reactions to proteins found on the outside of the
pollen grains. Different pollens cause allergies in different people because each type of
pollen has a different protein in the coats
of its pollen grains.
Chapter 23 • Introduction to Plants
Tomato sporophytes
The Vascular-Plant Sporophyte
As the size of plant sporophytes increased, so did the complexity of
their structure. An increase in size enables cell specialization and,
therefore, the development of complex tissues and specialized structures. The following features characterize the sporophytes of most
vascular plants.
Close
Reteaching
Vascular System Larger bodies require an efficient vascular system
for transporting materials internally. The sporophytes of vascular
plants have a vascular system with two types of vascular tissue. Each
type of vascular tissue contains strands of long, tubelike cells that are
lined up end to end like sections of pipe. These strands of cells transport water and nutrients within a plant’s body. Relatively soft-walled
cells transport organic nutrients in a kind of tissue called phloem
(FLOH uhm). Hard-walled cells transport water and mineral nutrients in a kind of tissue called xylem (ZIE luhm). The walls of the
water-conducting cells in xylem are
thickened, which helps support the
Shoot meristem
plant body. This makes it possible for
vascular plants to grow to great heights.
Co-op Learning
English Language
Learners
Quiz
GENERAL
1. True or false: nonvascular plants
Leaf
Distinctive Body Form Nearly all plants
have a body that consists of a vertical
shaft from which specialized structures
branch, as shown in Figure 8. The part
of a plant’s body that grows mostly
upward is called the shoot . In most
plants, the part of the body that grows
downward is called the root. Zones of
actively dividing plant cells, called
meristems (MEHR uh stehmz), produce
plant growth. The vertical body form
results as new cells are made at the tips
of the plant body. As vascular plants
became better adapted to life on land,
most developed the familiar plant structures—roots, stems, and leaves—which
are complex structures made of several
different types of specialized tissues.
Figure 8 Vascular plant
sporophyte. The sporophytes
of the vast majority of vascular
plants have an aboveground
shoot with stems and leaves
and an underground root.
Growth occurs in regions
called meristems.
Have students work in pairs to
review the key terms for this
section. Encourage each pair
of students to take turns asking
and answering questions
about the definitions of the
terms. LS Verbal
contain a well-developed system
of tissues that transport water
and nutrients. (False. Vascular
plants contain transporting tissues.)
2. What is the primary role of
flowers? (to promote pollination
by increasing its efficiency)
Stem
Alternative
Assessment
GENERAL
Students should work in pairs to
design and create a single poster
that illustrates the advantages
of vascular seedless plants over
nonvascular plants; the advantages
of seeds over spores; and the
advantages of flowering plants
over non-flowering seed plants.
Root
Root meristem
Section 1 Review
LS Visual Co-op Learning
TAKS 2 Bio 8C; TAKS 3 Bio 13A
Summarize how plants are adapted to living
Critical Thinking Evaluating Conclusions
successfully on land.
Why do you think vascular plants are more
successful as land plants than are nonvascular
7B 13A
plants?
7B 13A
Describe two basic differences between nonvas13A
cular plants and vascular plants.
Critical Thinking Relating Concepts How
have seeds and flowers made plants more
7B 13A
successful on land?
TAKS Test Prep Water loss from most plants
is reduced by a waxy layer called the
13A
A xylem.
C stomata.
B phloem.
D cuticle.
507
Answers to Section Review
1. The formation of a waxy cuticle, vascular tissues, drought-resistant reproductive structures
and seed development are adaptations that
enable plants to live on land. TAKS 3 Bio 7B, 13A
2. Vascular plants have a vascular system that
transports water, minerals, and sugars throughout the plant; nonvascular plants do not.
Nonvascular plant life cycles are dominated by
the gametophyte; vascular plants have a dominant sporophyte. TAKS 3 Bio 13A
3. Seeds and flowers have enabled plants to reproduce and disperse offspring without the aid of
water. Flowers have enabled plants to produce
offspring from fewer numbers of gametes
because animals often aid in fertilization. TAKS 3 Bio 7A (grade 11 only), 7B, 13A
4. Vascular plants are more successful on land
because adaptations have allowed them to reduce
their dependence on water. These include cuticle
protected leaves, vascular tissue, roots, taller
stems, and drought resistant spores or seeds. TAKS 3 Bio 7B, 13A
5.
A. Incorrect. The xylem carries
water and minerals throughout vascular plants.
B. Incorrect. The phloem carries sugars and
organic compounds in vascular plants.
C. Incorrect. Stomata are small holes in the leaves
of a plant that open to allow gas exchange and
close to limit water loss. D. Correct. The waxy
cuticle limits evaporation. TAKS 3 Bio 13A
Chapter 23 • Introduction to Plants
507
Section 2
Section 2
Kinds of Plants
Focus
Overview
Before beginning this section
review with your students the
objectives listed in the Student
Edition. This section introduces
the defining characteristics of the
different groups of plants. Students
will also identify several examples of
each group. These groups include
nonvascular plants, vascular seedless plants, gymnosperms, and
angiosperms.
Bellringer
On the board or overhead, write the
following headings: Nonvascular,
Seedless Vascular, Gymnosperm,
Monocot Angiosperm, and Dicot
Angiosperm. Ask students to write
the headings in their notebook, and
place at least one example under
each heading.
Nonvascular Plants
Objectives
● Describe the key features of
the four major groups of
plants.
13B
● Classify plants into one of the
12 phyla of living plants.
8C
TAKS 2
Key Terms
rhizoid
rhizome
frond
cone
gymnosperm
angiosperm
fruit
endosperm
monocot
dicot
The brilliant green carpet of mosses you see in Figure 9 is made up
of thousands of individual plants. Living carpets of mosses are often
found near streams, coastlines, and other moist places. But these
tough little plants also live in some surprising places, such as cracks
in city sidewalks and rocky mountaintops—any place where a little
moisture can collect. The moisture makes it possible for these nonvascular plants to survive.
Nonvascular plants do not have a vascular system for transporting water and other nutrients within their bodies. This means that
all nonvascular plants lack true roots, stems, and leaves, although
most have structures that resemble them. True roots, stems, and
leaves are complex structures that contain vascular tissues.
Key Features of Nonvascular Plants
In addition to the lack of true roots, stems, and leaves, nonvascular
plants share several other features. These features are key adaptations that have enabled them to survive on land.
Figure 9 A carpet of mosses. Mosses grow in
tightly packed mats that may contain dozens of plants
per square inch.
Small Size All nonvascular plants are small
and relatively simple. Water and other nutrients are transported within their bodies
mostly by osmosis and diffusion, which
move materials short distances. This greatly
limits the size of a nonvascular plant’s body.
Larger Gametophyte The gametophytes of
nonvascular plants are larger and more
noticeable than the sporophytes. Hairlike
projections called rhizoids anchor the gametophytes to the surfaces on which they grow.
The smaller, usually nongreen sporophytes
grow on the gametophytes and depend on
them for nutrients.
Motivate
Demonstration
Bring in living specimens or parts
of specimens of a variety of plants.
The collection should include as
many of the following as possible:
moss, liverwort, fern, horsetail,
conifer, cycad, ginkgo, a flowering
monocot (corn, iris, grass), and a
flowering dicot (rose, daisy, tomato,
etc.). Ask students to describe and
compare the characteristics of each,
noting both similarities and differences. (Differences may include size,
presence/absence of spores, flowers,
fruits, leaf shape, vein patterns, and
stiffness.) TAKS 2 Bio 8C
Require Water for Sexual Reproduction Non-
vascular plants must be covered by a film of
water in order for fertilization to occur.
Eggs and sperm form in separate structures,
which are often on separate plants. The
gametophytes grow in mats of tightly
packed individuals. When these mats are
covered by a film of water, the sperm can
easily swim to neighboring individuals and
fertilize their eggs.
508
Chapter Resource File
pp. 508–509
Student Edition
TAKS Obj 2 Bio 8C
TAKS Obj 3 Bio 7B
TAKS Obj 3 Bio 13A
TEKS Bio 7B, 8C, 13A, 13B
Teacher Edition
TAKS Obj 1 Bio/IPC 2B
TAKS Obj 2 Bio 8C
TEKS Bio 5A, 8C, 10C
TEKS Bio/IPC 2B
508
• Lesson Plan GENERAL
• Directed Reading
• Active Reading GENERAL
• Data Sheet for Data Lab
GENERAL
Transparencies
TT Bellringer
Chapter 23 • Introduction to Plants
Planner CD-ROM
• Reading Organizers
• Reading Strategies
• Portfolio Project
Plant Focus GENERAL
Kinds of Nonvascular Plants
The nonvascular plants include the mosses and the two simplest
groups of plants—liverworts and hornworts. Examples of these
plants are shown in Figure 10.
www.scilinks.org
Topic: Nonvascular Plants
Keyword: HX4130
Mosses The mosses (phylum Bryophyta) are the most familiar non-
Teaching Tip
vascular plants. The “leafy” green plants that you recognize as mosses
are gametophytes. Moss sporophytes, which are not green, grow from
the tip of a gametophyte. Each sporophyte consists of a bare stalk
topped by a spore capsule. Most mosses have a cuticle, stomata, and
some simple conducting cells. The walls of the water-conducting cells
in mosses are not thickened, as they are in a vascular plant. Mosses
never get very large because their water-conducting cells carry water
only short distances.
Liverworts Like the mosses, liverworts (phylum Hepatophyta) grow
in mats of many individuals. Liverworts have no conducting cells,
no cuticle, and no stomata. Their gametophytes are green. In some
species, such as the common liverwort shown in Figure 10, the
gametophytes of liverworts are flattened and have lobes. Structures
that resemble stems and leaves make up the gametophytes of most
liverworts, like those of the mosses. The sporophytes of liverworts
are very small and consist of a short stalk topped by a spore capsule.
Hornworts The hornworts (phylum Anthocerophyta) are a small
group of nonvascular plants that, like the liverworts, completely lack
conducting cells. Hornworts have both stomata and a cuticle. The
gametophyte of a hornwort is green and flattened. Green hornlike
sporophytes grow upward from the gametophytes.
The word liverwort
combines the familiar word
liver and the Old English
word wort, meaning “herb.”
The word liverwort dates
back to the Middle Ages,
when it was thought that
plants resembling certain
body parts could cure diseases of those body parts.
There are three phyla of nonvascular plants.
Marchantia, a liverwort
(Phylum Hepatophyta)
GENERAL
Mosses Have students observe
different types of mosses using a
stereomicroscope. They should find
both gametophyte and sporophyte
stages. Point out that the structures
resembling leaves on the moss
gametophyte are not considered
to be true leaves. Tell students that
a leaf is a complex structure that
consists of several specialized tissues.
Ask them whether they think the
sporophyte and gametophyte are
photosynthetic. (Only the gametophyte is photosynthetic.) Tell students
that the sporophyte is dependent
upon the gametophyte for survival.
LS Visual TAKS 2 Bio 8C; Bio 5A, 10C
SKILL
BUILDER
Math Skills Have students determine the mass of a small sample of
dry sphagnum (peat) moss, which
is available at garden centers. Have
students record the mass of the dry
moss. Next, have them place this
sample in a large beaker of water
for 10–15 minutes. Tell students
that 1kg of dry moss can soak up
approximately 25 kg of water.
Have students predict the mass of
their moss after soaking in water.
Have students remove the wet moss
from the beaker, and determine its
mass. Tell students to compare their
findings with their predictions. (The
mass of the wet moss should be about
25 times greater than the mass of the
dry moss.) TAKS 1 Bio/IPC 2B
Figure 10 Nonvascular plants
Polytrichum, a moss
(Phylum Bryophyta)
Teach
Anthoceros, a hornwort
(Phylum Anthocerophyta)
509
MEDICINE
CONNECTION
Tell students that moss has been used as an
antiseptic for centuries. Even in World War I,
moss was used to treat soldier’s wounds in
emergency situations. The antiseptic qualities
result from moss’ natural absorbency and
acidity.
MISCONCEPTION
ALERT
Mistaken Identity A variety of plants and
plantlike organisms are mistakenly called
mosses. Examples include Irish moss, Spanish
moss, and reindeer moss. Show photos of
these examples and reinforce the concept
that common names can be misleading. For
example, Irish moss is a red alga, Spanish
moss is a flowering vascular plant, and
reindeer moss is lichen.
Chapter 23 • Introduction to Plants
509
Seedless Vascular Plants
Teach, continued
continued
Teaching Tip
GENERAL
Local Habitats If your school
grounds contain a number of different habitats, take the students on
a tour of the campus. Otherwise,
schedule a trip to a nearby park.
Ask students to identify the habitats in which nonvascular plants
would most likely be found. (moist
habitats) Ask where vascular plants
would most likely be found. (any
habitat) Ask students to try to identify one nonvascular plant and one
vascular plant. Have them explain
what characteristics they used to
determine vascularity. (nonvascular:
moist habitat, small size, no flowers
or seeds; vascular: any habitat, large
or small, leaves with veins)
TAKS 2 Bio 8C; TAKS 3 Bio 13A
Using the Figure
GENERAL
Draw attention to Figure 11. Ask
students how Cooksonia resembles
plants that are alive today. (The
upright growth habit of these plants
and the location of the reproductive
structures resemble modern plants.)
Ask students how they differ from
the plants they are most familiar
with. (These primitive plants have no
leaves, roots, flowers, seeds, or fruits.)
www.scilinks.org
Topic: Seedless Vascular
Plants
Keyword: HX4161
Vascular plants that do not produce seeds are called seedless vascular plants. The earliest known seedless vascular plant, Cooksonia, is
illustrated in Figure 11. The sporophytes of these ancient plants had
branched, leafless stems that were only a few centimeters long.
Spore-forming sporangia were located at the tips of the stems.
Rhynia, another early seedless vascular plant, also had horizontal
underground stems, or rhizomes.
Key Features of Seedless Vascular Plants
Seedless vascular plants are much larger and more complex than
the nonvascular plants. Other key features enabled them to spread
and adapt to drier habitats on land.
Real Life
The spores of a common
club moss, Lycopodium,
form a powder that has
several uses.
Herbalists use the spores
to make a powder for
treating skin disorders.
The spores are also used
to make photographic
flash powder.
Finding Information
Find out how Lycopodium
powder is used by the
pharmaceutical industry.
Vascular System Seedless vascular plants have a vascular system
with both xylem and phloem. The water-conducting cells in the
xylem are reinforced with lignin, a major part of wood. Because of
their vascular system, seedless vascular plants grow much larger
than nonvascular plants and also develop true roots, stems, and
leaves.
Larger Sporophyte The sporophytes of seedless vascular plants are
larger than the gametophytes. Their larger size makes it easier for
the wind to carry away spores, which makes dispersal more efficient. The much smaller gametophytes of most seedless vascular
plants develop on or below the surface of soil. As in the nonvascular
plants, water is needed for fertilization. When there is enough water
on or in the soil, the sperm swim to eggs and fertilize them.
Drought-Resistant Spores The spores of the seedless vascular plants
have thickened walls that are resistant to drying. Such spores make
it possible for a plant to live in drier habitats.
Figure 11 The earliest known vascular plant
Cooksonia, the oldest known vascular plant, lived
about 410 million years ago.
TAKS 2 Bio 8C
Model of Cooksonia
510
Cultural
Awareness
pp. 510–511
Student Edition
TAKS Obj 2 Bio 8C
TAKS Obj 3 Bio 7B
TAKS Obj 3 Bio 13A
TEKS Bio 7B, 8C, 13A
Teacher Edition
TAKS Obj 2 Bio 8C
TAKS Obj 3 Bio 13A
TEKS Bio 5A, 8C, 13A, 13B
510
Edible Seedless Vascular Plants The
fiddleheads of ferns found in the forests of
the northeastern United States during the
spring were considered a delicacy by early
Native American groups. Edible fiddleheads
are actually the tightly coiled, emerging
fronds of the fern, Matteuccia struthiopteris.
Today, they are still used in American
cuisine. You may want to have interested
students research recipes for fiddleheads
or prepare some dishes for the class.
Chapter 23 • Introduction to Plants
Artist’s rendition of Cooksonia
Kinds of Seedless Vascular Plants
The seedless vascular plants include ferns and three other groups of
plants known as fern allies—whisk ferns, club mosses, and horsetails. Like the ferns, the fern allies usually grow in moist places.
Demonstration
Ferns The ferns (phylum Pterophyta) are the most common
and most familiar seedless vascular plants. Ferns grow
throughout the world, but they are most abundant in the
tropics. The plants you recognize as ferns are sporophytes.
Most fern sporophytes have a rhizome that is anchored by
roots and leaves called fronds. The coiled young leaves of a
fern, shown in Figure 12, are called fiddleheads. Spores are
produced in sporangia that grow in clumps on the lower side
of fronds. The gametophytes of ferns are flattened, heartshaped green plants that are usually less than 1 cm (0.5 in.)
across.
Club Mosses Unlike true mosses, the club mosses (phylum
Lycophyta), have roots, stems, and leaves. Their leafy green stems
branch from an underground rhizome. Spores develop in sporangia
that form on specialized leaves. In some species, such as the one
seen in Figure 13, clusters of nongreen spore-bearing leaves form a
structure called a cone.
Figure 12 A fern. This
sword fern sporophyte has
many fronds and fiddleheads.
The inset shows a gametophyte at twice its actual size.
Horsetails The horsetails (phylum Sphenophyta) also have roots,
stems, and leaves. The vertical stems of horsetails, which grow from
a rhizome, are hollow and have joints. Whorls of scalelike leaves
grow at the joints. Spores form in cones located at the tips of stems.
Bring examples of several kinds
of ferns to class, and have students
examine them. Also bring some
pictures of tree ferns, which are
native to many tropical regions.
Have students note the shapes of
the leaves and any fertile fronds or
sori present on the lower surface
of the fronds. Point out that there
are more than 12,000 species of
ferns on Earth today. Among these
species we find a tremendous
diversity of leaf form (from simple,
rounded leaves to lacy fronds with
hundreds of leaflets); plant shape
(moss-like to tree form); and plant
size (2.5 cm to 20 m tall).
LS Visual TAKS 2 Bio 8C; Bio 5A
Activity
Use a fern leaf from the demonstration above. Show students the
clusters of sporangia (sori) on the
lower surface of a frond. Let them
remove a sorus and crush it on
white paper using the eraser end
of a pencil. Next, have them sprinkle some spores on a moist peat
pellet and place the peat pellet in a
sealed jar. The first structures they
will observe will be the little green
heart-shaped gametophytes.
Whisk Ferns The whisk ferns (phylum Psilotophyta) probably most
closely resemble the earliest vascular plants. Whisk ferns have
highly branched stems and no leaves or roots. They produce spores
in sporangia that form at the tips of short branches.
Figure 13 Fern allies
In addition to ferns, there are three other living phyla of seedless vascular plants
that are known as fern allies.
LS Kinesthetic Bio 5A, 13B
READING
SKILL
BUILDER
Psilotum, a whisk fern
(Phylum Psilotophyta)
Lycopodium, a club moss
(Phylum Lycophyta)
Equisetum, a horsetail
(Phylum Sphenophyta)
511
Cultural
Awareness
Introduced Species Can Replace Native
Species Cultures that spread to new regions
of the Earth often bring familiar plant and
animal species with them, sometimes with
disastrous results. Settlers introduced pigs on
the island of Hawaii as a source of food, but
these animals wiped out native vegetation.
Additionally, the settlers brought their own
plants, which eventually crowded out native
species. The people of Hawaii are now trying
to reclaim their native plants, including tree
ferns. Have students research introduced
plants in their own area that are threatening
native plant communities.
Reading Organizer Encourage
students having difficulty to use
the information on this page to
make a chart that outlines the
differences between ferns, club
mosses, horsetails, and whisk
ferns. English language learner
students may want to fill in the
chart in their
English Language
Learners
native language.
TAKS 2 Bio 8C
Chapter 23 • Introduction to Plants
511
Gymnosperms
Gymnosperms (JIHM noh spurmz) are seed plants whose seeds do
not develop within a sealed container (a fruit). The word gymnosperm
comes from the Greek words gymnos, meaning “naked,” and sperma,
meaning “seed.”
Teach, continued
continued
Activity
GENERAL
Gymnosperms are among the most successful groups of plants. The
following key features have made them successful on land.
Seeds All gymnosperms produce seeds. Seeds protect plant
Figure 14 Juniper pollen.
This juniper, a type of
gymnosperm, releases clouds
of pollen in late fall or early
winter.
Analyzing the Effect
of Climate on Plants
0100010110
011101010
0010010001001
1100100100010
0000101001001
1101010100100
0101010010010
water to reach and fertilize eggs. Instead, the sperm are carried to
the structures that contain eggs by pollen, which can drift on the
wind, as seen in Figure14. Wind pollination makes sexual reproduction possible even when conditions are very dry.
Teacher’s Notes
Point out that the bar graph
represents precipitation
and that the line graph
represents temperature.
1. Answers may vary. Anchorage
temperatures average at or
below freezing for six months
of the year. Precipitation is
highest in summer and fall, and
relatively low in other seasons.
2. Answers should predict that
the taiga shares a similar plant
community, the taiga outside
of Anchorage should have a
fairly similar climate.
3. Yes. Explanations should rely on
the map for reasoning. The taiga
species are not found further
north or south. Soil type or
human activities are also valid
explanations. TAKS 1 Bio/IPC 2A
Analyzing the Effect of
Climate on Plants 2C 13A
0100010110
011101010
0010010001001
1100100100010
0000101001001
1101010100100
0101010010010
Background
The map at right shows the taiga of North America. The
taiga is a vast forest of conifers, a type of gymnosperm.
The graph shows average annual temperature and precipitation data for Anchorage, Alaska, which is located
at the western edge of the taiga. Use the map and
graph to answer the following questions.
1. Describe the climate of
Anchorage, Alaska.
2. Critical Thinking
Predicting Patterns
What type of climate would
you expect to find in other
parts of the taiga?
512
Student Edition
TAKS Obj 1 Bio/IPC 2C
TAKS Obj 2 Bio 8C
TAKS Obj 3 Bio 7B
TAKS Obj 3 Bio 13A
TEKS Bio 7B, 8C, 13A
TEKS Bio/IPC 2C
Teacher Edition
TAKS Obj 2 Bio 8C
TAKS Obj 3 Bio 7A
TEKS Bio 3D, 7A, 8A, 8C
Chapter 23 • Introduction to Plants
60° N
TAKS 1, TAKS 3
Analysis
pp. 512–513
512
Greatly Reduced Gametophytes All seed plants produce very tiny
gametophytes of two types—male and female. The gametophytes
form within the tissues of the sporophytes. Grains of pollen are
male gametophytes. Female gametophytes form within structures
that become seeds. In all but one species of gymnosperm, male
and female gametophytes develop in male and female cones,
respectively.
Wind Pollination The sperm of gymnosperms do not swim through
TAKS 3
Skills Acquired Bio 13A
Analyzing data, interpreting graphs, drawing
conclusions
Answers to Analysis
embryos, provide them with nutrients, and permit them to survive
long periods of unfavorable conditions. In some plants, seeds also
disperse new plants far from their parents.
3. Critical Thinking
Drawing Conclusions
Does climate appear to be
an important factor in where
the conifers of the taiga
grow? Explain.
30° N
Taiga
Anchorage, Alaska
40
20
30
0
20
–20
10
–40
–60
0
J FMAMJ J ASOND
Months
Temperature (°C)
TAKS 2 Bio 8C; Bio 8A
Key Features of Gymnosperms
Precipitation (cm)
Conifer ID Obtain cuttings of
several conifers. Then have students
construct their own keys, which
they can use to identify the species.
Students may look at cones, needle
size, needle shape, needle organization, and needle color. Then supply
students with keys or field guides
and ask them to correctly identify
their samples. LS Kinesthetic
Kinds of Gymnosperms
Four groups of living seed plants are referred to as
gymnosperms—conifers, cycads, ginkgo, and gnetophytes. Examples of each of these four groups are
shown in Figure 15 and Figure 16.
READING
SKILL
BUILDER
Conifers The conifers (phylum Coniferophyta) are
the most familiar, and most successful, gymnosperms. Conifers have leaves that are either
needle-like or reduced to tiny scales, as Figure 15
shows. These leaves are an adaptation for limiting
water loss. Some of the tallest living plants, the redwoods of coastal California and Oregon, are conifers.
The oldest trees in the world are thought to be bristlecone pines,
another species of conifer that grows in the Rocky Mountains. Some
bristlecone pines are about 5,000 years old. Vast forests of conifers
grow in cool, dry regions of the world.
Cycads The cycads (phylum Cycadophyta) have short stems and
palmlike leaves. Cones that produce pollen and those that produce
seeds develop on different plants. Cycads are widespread throughout the tropics.
Figure 15 Juniper
leaves and cones. The tiny
scalelike leaves of junipers—a
type of conifer—are an adaptation that limits water loss.
The blue, berrylike structures
are the female cones of this
juniper.
Discussion Lead the class in
brainstorming the characteristics
they have observed in pine trees.
(They stay green all year; have
thin, needle-like leaves; have
pinecones.) Stress that while
this section provides additional
information about gymnosperms,
students already know a great deal
about them. Encourage English
language learners to translate
the list into their
English Language
Learners
native language.
Career
Ginkgo The only living species of ginkgo (phylum Ginkgophyta), or
maidenhair tree, has fan-shaped leaves that resemble the leaves of
the maidenhair fern. The male and female gametophytes of ginkgo
develop on separate trees. Ginkgo seeds do not develop within a cone.
Botanist A botanist studies
plants and their environments.
Most botanists specialize in a particular area. For example, plant
physiologists study the structural
parts of plants and how they function; plant breeders study the ways
in which plants reproduce and
how their traits are inherited’
horticulturists work with crops
such as flowers, fruits, and vegetables; agronomists work with crops
such as grains and dry beans; and
foresters study all aspects of tree
growth. Have students research a
field of botany that interests them
and prepare a written report on
career opportunities in that field.
Gnetophytes The gnetophytes (phylum Gnetophyta) are a diverse
group of trees, shrubs, and vines that produce pollen and seeds in
cones that resemble flowers. One type of gnetophyte, Ephedra, is
common in the western United States.
Figure 16 Other gymnosperms
In addition to conifers, there are three other living phyla of gymnosperms.
Bio 3D
Encephalartos, a cycad
(Phylum Cycadophyta)
Leaves and seeds of Ginkgo
(Phylum Ginkgophyta)
Ephedra (Mormon tea), a gnetophyte
(Phylum Gnetophyta)
513
MISCONCEPTION
ALERT
Supplements made from Ginkgo biloba and
other plants are commonly sold in grocery,
drug, and health food stores. Students may
think that a substance called an herbal supplement is not a drug. In fact, many herbal
supplements act as drugs, though they are
not regulated by the Food and Drug
Administration. Have students examine
advertisements for common herbal supplements and infer which claims could be substantiated experimentally and which claims
are more difficult to verify. Bio 3B
did you know?
Living Fossils The ginkgo, or maidenhair tree,
is considered a “living fossil” because it was
once thought to be extinct. The ginkgo is the
only broadleaf gymnosperm still surviving, and
it closely resembles fossil specimens. In 1994,
another gymnosperm thought to be extinct for
100 million years was discovered in a rain forest near Sydney, Australia. A small population
of Wollemi pines, a prehistoric type of conifer
belonging to a family that was thought to have
become extinct along with the dinosaurs, was
found by a park ranger. This ancient family of
trees once spread into the Northern Hemisphere.
TAKS 2 Bio 7A (grade 11 only)
Chapter 23 • Introduction to Plants
513
Angiosperms
Teach, continued
continued
Demonstration
GENERAL
Most seed plants are flowering plants, or angiosperms (AN jee oh
spurmz). Angiosperms produce seeds that develop enclosed within a
specialized structure called a fruit, as seen in Figure 17. The word
angiosperm comes from the Greek words angeion, meaning “case,”
and sperma, meaning “seed.”
www.scilinks.org
Topic: Angiosperms
Keyword: HX4007
Bring several examples of cones
(pine, spruce, fir, yew) and flowers
(iris, daisy, gladiolus, etc) to class,
and have students examine and
compare each of these types of
reproductive structures. (Both
produce seeds; flowers have petals,
stamens, and pistils, and cones do
not; cones have scales.) LS Visual
Key Features of Angiosperms
Angiosperms are the most recent group of plants to evolve. The following key features made them the most successful group of plants.
Flowers The male and female gametophytes of angiosperms
develop within flowers, which promote pollination and fertilization
more efficiently than do cones. Some flowers, such as roses, are
brightly colored or have strong scents. This attracts insects and
other animals that carry pollen and increases the likelihood of crosspollination. Other flowers, such as garden peas, are adapted for selfpollination, which often occurs before the flowers open. The flowers
of many angiosperms, such as oaks and grasses, have small greenish
flowers that are adapted for wind pollination. The female reproductive part of a flower also provides a pathway that enables sperm to
reach and fertilize eggs without swimming through water.
Bio 5A, 13B
Teaching Tip
GENERAL
Charting Information Have students make a Graphic Organizer
similar to the one at the bottom of
this page to compare and contrast
the characteristics of the major
plant groups. Ask students to
illustrate their graphic organizer
with a drawing of a plant in each
of the major groups. LS Kinetic
TAKS 1 Bio/IPC 2C; TAKS 2 Bio 8C
Fruits Although fruits provide some protection for developing seeds,
their primary function is to promote seed dispersal. The angiosperms
produce many different types of fruits, which develop from parts of
flowers. Many fruits are eaten by animals. The seeds are dispersed as
they pass undigested from the animals’ bodies. Other fruits have
structures that help them float on wind or water. Some fruits even
forcefully eject their seeds, flinging them away from the parent plant.
www.scilinks.org
Topic: Texas Desert Plants
Keyword: HXX4013
Endosperm The seeds of angiosperms have a supply of stored food
called endosperm at some time during their development. In many
angiosperms, the endosperm is absorbed by the embryo before the
seeds mature.
Transparencies
TT Life Cycle of an Angiosperms
TT Familiar Families of Angiosperms
Figure 17 Seeds in a fruit.
These melons, which contain
seeds, are the fruits of an
angiosperm.
514
Graphic Organizer
pp. 514–515
Student Edition
TAKS Obj 2 Bio 8C
TAKS Obj 3 Bio 7B
TAKS Obj 3 Bio 13A
TEKS Bio 7B, 8C, 13A, 13B
Teacher Edition
TAKS Obj 1 Bio/IPC 2C
TAKS Obj 2 Bio 8C
TAKS Obj 3 Bio 13A
TEKS Bio 5A, 8A, 8C, 10C, 13A, 13B
TEKS Bio/IPC 2C
514
Use this graphic organizer with Teaching Tip
on this page.
Phylum
Liverworts
Mosses
Ferns
Conifers
Flowering plants
Chapter 23 • Introduction to Plants
Vascular system Roots Seeds
Flowers
Dominant
gametophyte
Dominant
sporophyte
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
Kinds of Angiosperms
Figure 18 A monocot and a dicot
Botanists divide the angiosperms
into two subgroups—monocots and
dicots as Figure 18 shows. The
monocots are flowering plants that
produce seeds with one seed leaf
(cotyledon). Most monocots also
produce flowers with parts that are
in multiples of three and have long,
narrow leaves with parallel veins.
The dicots are flowering plants that
produce seeds with two seed leaves.
Most dicots also produce flowers
with parts in multiples of two, four,
or five and have leaves with branching veins. Table 1 lists examples of
some of the most familiar families
of angiosperms.
Monocots and dicots differ in several ways.
Activity
Classifying Plants as Monocots
or Dicots Provide examples
and pictures of a variety of plants,
including both dicots and monocots.
Let students determine whether the
examples are dicots or monocots.
Point out that some plants are
not easily placed into one of
the groups, such as pothos ivy.
Botanists usually rely on flower
structure in such cases. LS Visual
Roses are dicots.
Daylilies are monocots.
TAKS 2 Bio 8C; Bio 13B
Close
Table 1 Familiar Families of Angiosperms
Subgroup
Monocots
(class
Monocotyledonae)
Dicots
(class Dicotyledonae)
Family
Reteaching
Examples
Iridaceae (iris)
Irises, gladiolus, crocus, blue-eyed grass
Liliaceae (lily)
Daylilies, tulips, asparagus, aloe vera
Poaceae (grass)
Wheat, corn, rice, lawn grasses
Asteraceae (composite)
Daisies, sunflowers, lettuce, ragweed
Brassicaceae (mustard)
Broccoli, cauliflower, turnips, cabbage
Fabaceae (legume)
Beans, clovers, peas, peanuts, soybeans
Rosaceae (rose)
Roses, apples, peaches, pears, plums
Solanaceae (nightshade)
Potatoes, tomatoes, peppers, petunias
Have students write down the key
characteristics of each major group
of plants discussed in this section.
For each major group, have students
provide one example. Then choose a
student to read a description aloud,
and allow fellow students to interrupt as soon as they recognize the
group being described. Continue
until all groups have been described
at least twice.
Quiz
GENERAL
1. Mosses, liverworts, and horn-
Section 2 Review
Identify three key features of each of the four
Critical Thinking Recognizing Patterns
major groups of plants.
How are spores and pollen grains adapted for
their functions, and how do their numbers impact
13A
their environment?
13B
Classify each of the following plants into one of
the phyla of living plants: pine trees, carnations,
8C
sphagnum moss, and wood fern.
Critical Thinking Evaluating Conclusions
Why are angiosperms said to be the most
13A
successful group of plants?
TAKS Test Prep
producing
A spores.
B cones.
Ferns reproduce by
13B
C flowers.
D seeds.
515
Answers to Section Review
1. Nonvascular plants lack a vascular system, roots
and true leaves; have a larger gametophyte generation, and produce spores. Seedless vascular
plants have a vascular system, roots, and leaves;
release spores; and have a larger sporophyte generation. Gymnosperms have a vascular system,
roots, and leaves; produce spores; and have a
larger sporophyte. Angiosperms have a vascular
system, roots, leaves, and flowers; produce fruits
and seeds; have a larger sporophyte. Bio 13B
2. Pine trees are gymnosperms; carnations are
angiosperms; sphagnum moss is a nonvascular
plant; and wood fern is a seedless vascular
plant. TAKS 2 Bio 8C
worts are examples of ________
plants. (nonvascular)
2. Gymnosperms reproduce by
seeds that are produced in
________. (cones)
3. Plants that produce flowers with
parts in groups of three are classified as ________. (monocots)
Alternative
Assessment
Have students create a guide to
the plants in the area. Students
should create a booklet with the
3. Angiosperms are successful partly because they
following sections: Nonvascular
produce fruits that provide a mechanism for seed
dispersal by wind, water, or animals. TAKS 3 Bio 13A Plants, Seedless Vascular Plants,
Gymnosperms, Monocots, and
4. Spores and pollen grains have coats that are
Dicots. Students should identify and
resistant to harsh environmental conditions.
record at least two species for each
They may be transported by the wind or by
section of their booklet. Bio 8C, 10C
animals. The large amount of spores or pollen
produced helps ensure reproduction and colonization of new environments. TAKS 3 Bio 13A
5.
A. Correct. B. Incorrect.
Gymnosperms reproduce by producing cones.
C. Incorrect. Angiosperms reproduce by producing flowers. D. Incorrect. Ferns do not
produce seeds Bio 13B
Chapter 23 • Introduction to Plants
515
Section 3
Section 3
Plants in Our Lives
Focus
Overview
Objectives
Plants as Food
Before beginning this section
review with your students the
objectives listed in the Student
Edition. This section examines some
of the many ways that humans use
plants. Students will learn about
food plants, including cereal grasses
and other crops. This section will
also discuss the many ways that
trees can be used, including the
chemicals and fibers obtained from
trees and other plants.
● Identify foods that come
from plants and their dietary
importance.
13A TAKS 3
Humans depend on plants in many ways. For one thing, plants store
the extra nutrients they make or absorb in their bodies. Thus, plant
parts contain organic nutrients (carbohydrates, fats, and proteins)
and minerals (calcium, magnesium, and iron). All types of plant
parts—roots, stems, leaves, flowers, fruits, and seeds—are eaten
as food.
Bellringer
Ask students to make a list of the
different plant parts that can be
eaten as food. (Students should list
leaves, roots, stems, fruits, seeds,
flowers, buds, bulbs, tubers, and
shoots.) Ask students to name any
other products that plants provide
people. (Answers will vary, but may
include wood, fibers for paper and
textiles, medicines, chemicals, dyes,
and oxygen.) Bio 10C
● Describe several ways that
wood is used.
13A TAKS 3
● Explain how plants are
used to treat human
ailments.
13A TAKS 3
● Identify plants that are
used to make paper and
13A TAKS 3
cloth.
Key Terms
vegetative part
cereal
grain
Fruits and Vegetables
The United States government identifies each of the foods that
comes from a plant as an agricultural commodity. Each type of food
is classified by a term—such as fruit or vegetable—that is registered
in Washington, D.C. But, these terms have different meanings in
botany. For example, to a botanist, a fruit is the part of a plant that
contains seeds, and a vegetative part is any nonreproductive part of
a plant. The foods that you think of as fruits—such as apples,
bananas, and melons—are also fruits in the botanical sense.
Vegetables, on the other hand, may be any botanical part of a plant,
as you can see in Figure 19. Fruits and vegetables provide dietary
fiber and are important sources of essential vitamins and minerals.
Figure 19 Plant parts eaten as food
The foods you eat come from different parts of plants.
Fruits
Flowers
Shoots
Motivate
Leaves
Discussion
GENERAL
Ask students to consider all of
the ways plants contribute to our
survival and way of life. Allow
students to brainstorm and develop
a list, then open the question for
discussion. Ask students how much
of their food, clothing, books,
furniture, pencils, paper, oxygen,
medicine, etc. comes from plants.
Ask them to consider life without
plants. What would people use
instead of plants? (Answers will vary.)
LS Interpersonal
Storage structures
Roots
516
REAL WORLD
CONNECTION
pp. 516–517
Student Edition
TAKS Obj 2 Bio 6D
TAKS Obj 2 Bio 8C
TAKS Obj 3 Bio 13A
TEKS Bio 6D, 8C, 13A
Teacher Edition
TAKS Obj 2 Bio 6D
TEKS Bio 6D, 10C, 13B
516
Leafy vegetables are an important source of
nutrition. Most greens can be eaten cooked or
raw. Many varieties are rich in beta-carotene,
vitamin C, folic acid, calcium, and iron. In
general, darker leaves are more nutritious
than lighter-colored leaves. Have students
check references on nutrition (such as the
USDA’s Composition of Foods) for vitamin,
mineral, and fiber content of a variety of leafy
green vegetables, as well as other fruits and
vegetables and commonly eaten snack foods.
Allow students to compare their results with
each other.
Chapter 23 • Introduction to Plants
Chapter Resource File
• Lesson Plan GENERAL
• Directed Reading
• Active Reading GENERAL
• Datasheet for Quick Lab
GENERAL
Transparencies
TT Bellringer
Root Crops
Potatoes are an important food staple in many parts
of the world. Rich in calories and easy to grow, potatoes are an ideal crop for a small farm. Potatoes are
classified as a root crop because they grow underground. But, potatoes are actually tubers, modified
underground stems that store starch. Yams, an essential food crop in many tropical parts of the world, are
also tubers. Sweet potatoes, carrots, radishes, turnips,
beets, and cassava (kuh SAH vuh) are also important
root crops. These vegetables are enlarged roots that
store starch. Cassava, seen in Figure 20, is the staple food of more
than 500 million people. Also known as manioc (MAN ee awk),
cassava supplies more than one-third of the calories eaten in Africa.
Legumes
Many members of the pea family, which are called legumes, produce
protein-rich seeds in long pods. For example, about 45 percent of a
soybean, the most important legume grown for food, is protein.
Soybeans are often cooked and pressed into cakes called tofu (TOH
foo). Peas, peanuts, and the many different types of beans are the
seeds of legumes. Alfalfa, which is fed to livestock, is another important legume. Like many legumes, alfalfa has nitrogen-fixing bacteria, which add nitrogen compounds to the soil, in its roots.
Therefore, alfalfa is also grown to enrich the soil.
Teach
READING
SKILL
BUILDER
Figure 20 Cassava.
Cassava develops thick
starch-filled roots up to 120
cm (4 ft) long. The roots are
eaten like potatoes. Tapioca,
shown above in the bowl, is
made from cassava.
Distinguishing Fruits
and Vegetables 6D TAKS 2
Differentiating
Fruits and Vegetables
You can find out if a plant product is a fruit by cutting it open and examining its internal structure.
TAKS 2 Bio 6D; Bio 10C, 13B
Materials
Skills Acquired
Analyzing data, analyzing results, drawing
conclusions
apple, banana, green bean, potato, squash, tomato,
plastic knife
Procedure
1. Look at several familiar fruits
and vegetables. Classify each
one as either a fruit or a vegetable in the familiar sense.
3. Look at the fruits and vegetables again. Classify each by
its botanical function—either
a fruit or a vegetative part.
2. Critical Thinking
Analyzing Data Which
fruits and vegetables did you
classify differently?
2.
Analysis
3. Critical Thinking
Analyzing Results Defend
the classifications you made
for item 2.
CAUTION: Sharp
objects can cause
injury. Handle knives carefully. Use a plastic knife to cut
open each fruit and vegetable.
Anticipation Guide Before
students begin this section, write
the following statements on the
board or overhead projector:
1. Wood is the most valuable
resource that people get from
plants.
2. Most of the food that people eat
comes from fruits.
3. Plants produce many chemicals
that are useful as medicines, but
none that are poisonous.
Ask students to decide whether they
agree or disagree with each statement. Ask volunteers to share the
reasons for their opinions. Have students read the chapter to see if their
opinions are confirmed or changed.
1. Compare the familiar
and botanical classifications
you gave each fruit and
vegetable.
4. Critical Thinking
Drawing Conclusions
Based on your data, when is
a vegetable a fruit?
517
Cultural
Awareness
Cassava The staple crop of Brazil and many
other tropical and subtropical countries is
a perennial shrub root called cassava, or
manioc. It is asexually propagated from
tuberous roots. These starchy roots contain
compounds that form cyanide, which must
be removed through processing before eating.
The roots are usually ground into flour and
used in cooking. Processing methods are
complex, labor intensive, and pose a risk of
cyanide poisoning to processors. In Brazil,
toasted cassava meal, or “farofa,” is served
at most meals. Cassava is also used to make
tapioca and beer in some cultures. There are
bitter and sweet varieties of cassava, with
varying levels of toxicity. Worldwide, cassava
helps to feed more than 500 million people.
Teacher’s Notes
Point out that some true fruits
might not have obvious seeds.
Commercially produced bananas
are sterile triploids (3n). The
fruit is large but the seeds are
difficult to see and not viable.
Answers to Analysis
1. Apples and bananas are true
fruits. Green beans, squash,
and tomatoes are true fruits
that most people would identify
as vegetables. Potatoes are
vegetative structures that are
familiarly called vegetables.
2. Students will probably need to
reclassify green beans, squashes,
and tomatoes as fruits.
3. True fruits contain seeds, many
of the “vegetables” in this lab
contain seeds which makes
them true fruits.
4. A “vegetable” is a fruit if it
is produced from a flower,
contains parts of the flower
(ovary), and contains seeds.
Chapter 23 • Introduction to Plants
517
Cereals
Most of the foods that people eat come directly or indirectly from
the fruits of cereals. Cereals are grasses that are grown as food for
humans and livestock. Cereal grasses produce large numbers of a
type of edible, dry fruit called a grain . A grain contains a single seed
with a large supply of endosperm. Each grain develops from a
flower. The flowers of cereal grasses form in tightly packed clusters
of many individual flowers. A grain is covered by a dry, papery husk
called the bran, which includes the wall of the ovary and the seed
coat. Cereal grains are rich in carbohydrates and also contain protein, vitamins, and dietary fiber. More than 70 percent of the world’s
cultivated farmland is used for growing cereal grains. In fact, more
than half of the calories that humans consume come from just three
cereal grasses: wheat, corn, and rice.
Teach, continued
continued
Teaching Tip
GENERAL
Small Selection of Crops
Tell students that approximately
80,000 species of plant species
produce edible parts, but only
50 of these are cultivated as major
food sources. Seven of these
species—rice, wheat, corn, barley,
sorghum, potatoes, and cassava—
make up 75 percent of the food
consumed around the world.
SKILL
BUILDER
Wheat
GENERAL
Math Skills Tell students that of
the 560 million metric tons of
wheat produced around the world
each year, 20 percent is used to
feed livestock, and 80 percent feeds
humans directly. Of the 520 million
metric tons of rice produced, almost
100 percent feeds humans. Finally,
of the 530 million metric tons of
corn produced, 65 percent is used
to feed livestock, the rest going
directly to humans. Have students
calculate the amount of each crop
eaten by humans (in metric tons),
then prepare bar graphs to display
this information. Have students
describe this information in writing, and rank each crop in terms
of the amount eaten by humans.
(Rice is the most important, at nearly
520 million metric tons; wheat is
second, at 448; and corn is third,
at 185.5 million metric tons.)
LS Logical TAKS 1 Bio/IPC 2C, 2D
Figure 21 Wheat. Modern
bread wheat is a hybrid of
three wild species. The
ripenend heads of bread wheat
turn golden brown.
For more than one-third of the world’s population, wheat, seen in
Figure 21, is the primary source of food. The endosperm of wheat
grains, which is high in carbohydrates, is commonly ground into
white flour and used to make breads and pasta. Vitamin-rich wheat
germ consists of the embryos of wheat grains. Whole-wheat flour
consists of the endosperm plus the germ and bran layers. Wheat
grains are not always ground into flour. In the Middle East, wheat
grains are often boiled or soaked, dried, and then pounded until they
crack. The cracked grains, called bulgur (BUL guhr), are used in
dishes such as tabbouleh (tuh BOO lee) and pilaf (pih LAHF). Most
wheat is grown in temperate regions that have fertile soil and moderate rainfall. One of the world’s best wheat-growing areas is the
Great Plains region of the United States and Canada—a temperate
grassland biome.
Corn
Figure 22 Corn. Each ear
of corn developed from a
flower spike that consisted of
more than 500 flowers.
Corn, seen in Figure 22, is the most widely cultivated crop in the
United States. American colonists of the 1600s and 1700s first
learned how to grow corn from Native Americans. In the southeastern United States, corn was more widely grown than wheat, which
does not grow as well in hot climates. Thus, foods that are made
from corn—corn bread, corn pone, hominy, and grits—are a traditional component of the southeastern American diet. Corn is also
one of the world’s chief foods for farm animals. About 70 percent of
the corn crop harvested in the United States is consumed by livestock. Other uses for corn include the production of corn syrup,
margarine, corn oil, cornstarch, and fuel-grade ethanol. Most of the
corn grown in the United States today comes from a region known
as the Corn Belt, which includes Iowa, Nebraska, Minnesota,
Illinois, and Indiana.
518
did you know?
pp. 518–519
Student Edition
TAKS Obj 2 Bio 6D
TAKS Obj 3 Bio 7B
TAKS Obj 3 Bio 13A
TEKS Bio 6D, 7B, 8C, 11C, 13A
Teacher Edition
TAKS Obj 1 Bio/IPC 2C, 2D
TEKS Bio/IPC 2C, 2D, 3C
TEKS Bio 3F, 11C
518
Wheat Strains Help Mexico In 1944 new
strains of wheat helped end food shortages in
Mexico. Norman Borlaug, who helped launch
the Green Revolution, was awarded the Nobel
Prize in 1970 for developing new strains of
wheat in Mexico. His research on wheat began
in 1944. Within 20 years, Mexico had enough
wheat not only to feed its own people but also
to export to other countries. India and Pakistan
experienced similar successes. Borlaug’s highyielding strains were produced from crosses
with a dwarf variety. Bio/IPC 3C, Bio 3F
Chapter 23 • Introduction to Plants
Planner CD-ROM
• Reading Organizers
• Reading Strategies
• Portfolio Project Plant Research
Project GENERAL
Rice
For more than half of the people in the
world, rice is the main part of every
meal. Although it is low in protein,
rice is an excellent source of energyrich carbohydrates. While brown rice
still has its vitamin-rich bran layers,
white rice has been processed to
remove the bran layers. This processing helps to prevent spoilage in stored
rice. In societies where people eat
mainly rice, vitamin-rich sauces such
as soy sauce are often added to white
rice to make meals more nutritious.
The white rice you buy at a grocery
store is enriched with added vitamins.
Rice is often added to processed foods
such as breakfast cereal, soup, baby food, and flour. In the United
States, rice is grown in central California, in the Southeast, and
along the Gulf Coast in fields such as the one shown in Figure 23.
Group Activity
Figure 23 Texas rice
field. Rice plants are grown in
standing water.
Local Plant Processing Have
students work in groups of three or
four. Ask them to prepare a report
describing 10 plant-based products
made within a 150km radius of
the school. Some possible products
include cereals and other crops,
food processing, forestry, furniture,
wood products, nurseries and
greenhouses; textiles, plant-based
cosmetics, plant-based medicines
and supplements, and paper production or paper recycling. As part
of the project, have students create
a map with the school at its center
and the various plant-based
industries located on the map.
Co-op Learning
TAKS 1 Bio/IPC 2C, 2D
Vegetarian Diets
GENERAL
M
any people are vegetarian;
they eat only foods from
plants. Like any diet, vegetarian
diets must satisfy the body’s
nutritional needs to be healthy.
Two important considerations in
eating a healthy vegetarian diet
are the essential amino acids
and vitamins B-12 and D.
Getting the Essential
Amino Acids
Essential amino acids is the term
for those amino acids that the
human body cannot make. Most
plant proteins contain all of the
essential amino acids, but in different relative amounts. For
example, cereal proteins tend to
be low in lysine and high in
methionine; the opposite is true
for the proteins in beans.
Traditionally, cereals and beans
are eaten together to obtain
enough of the essential amino
acids. However, vegetarians can
get the essential amino acids they
need even if they do not eat a
variety of plant foods, as long as
they eat enough protein. For
example, if you eat enough rice to
satisfy your daily protein requirement, you will get more than twice
your daily requirement for lysine.
The recommended daily requirement for protein is 44 g for a 55 kg
(121 lb) woman and 56 g for a
70 kg (154 lb) man. Legumes,
grains, nuts, broccoli, and potatoes are good sources of protein.
Vitamins B-12 and D
A vegetarian diet generally can
provide enough of all but two vitamins, vitamin B-12 and vitamin D.
To get enough vitamin B-12,
Vegetarian Diets
vegetarians can eat fortified foods,
add eggs or dairy products to their
diet, or take vitamin B-12 supplements. Vitamin D is made in the
skin when it is exposed to sunlight. Vegetarians may need to
take vitamin D supplements if their
exposure to sunlight is limited.
www.scilinks.org
Topic: Vegetarian Diets
Keyword: HX4184
519
Cultural
Awareness
Rice and Culture Rice plays an important
part in the customs and economies of many
cultures where it is a major food source. For
example, Japanese place a shiminawa, or
rice-straw rope, over an entrance to ward
off evil. The largest rope in the world is a
shiminawa that hangs over the entrance to
the Izumo Shinto Shrine and weighs 6 metric
tons. Rice is the symbol of the goddess of
wealth and prosperity and is often worshiped
as a goddess by the Hindu. The act of pouring
rice over someone’s head signifies prosperity
and happiness. Students may find this amusing. Remind them of the familiar western
custom of throwing rice at a wedding.
11C
Teaching Strategies
Bring in cookbooks or pictures
of vegetarian meals that provide
good quality and quantity of
essential amino acids and are
good sources of vitamins B-12
and D. Some examples are bean
and cheese tacos on wheat or
corn tortillas and tofu with rice
and green vegetables. Point out
that in many parts of the world,
the majority of calories come
from combinations of grains
and legumes. (South America:
corn and beans; Asia: rice and
soybeans)
Discussion
After students have read the
feature, ask students: Which
essential amino acids are commonly abundant in meat
products but low in cereal
grains and legumes? (lysine, is
low in cereal grains; methionine,
is low in legumes) Why is a varied diet that includes animal
products, such as milk, eggs,
and cheese, important for vegetarians? (A varied diet is more
likely to provide all the essential
amino acids and vitamins, some
of which are hard to obtain from
non-animal products.)
Chapter 23 • Introduction to Plants
519
Nonfood Uses of Plants
Plants are used by people for many purposes other than food. For
example, rubber was first made from latex, the milky white sap of
tropical trees of the genus Hevea. Latex is extracted from rubber
trees by the method seen in Figure 24. Guayule (gwah YOO lee), a
member of the sunflower family that is native to the southwestern
United States, is another source of natural rubber. (Most of today’s
rubber, however, is synthesized from petroleum, a nonrenewable
resource.) The most important nonfood products obtained from
plants are wood and fibers.
Teach, continued
continued
Demonstration
GENERAL
Bring the following to class: some
biodegradable packing pellets, some
Styrofoam peanut pellets, 2 beakers
of water, and iodine in a dropper
bottle. To show the advantages of
biodegradable products, drop a
few of the biodegradable packing
pellets into a beaker of water. Stir
until dissolved. Add several drops
of iodine to the beaker, and note
color change. Ask students to identify the composition of the pellets.
(Purple indicates starch, from corn in
this case.) Repeat the procedure with
the Styrofoam peanuts. Point out
that both products are reusable, but
only the cornstarch-based pellets
will easily biodegrade. Bio/IPC 1B
Activity
GENERAL
Paper Types Have students make
wet-mount slides of various types
of paper and then observe the slides
under a microscope. Staining the
paper with methylene blue will
make the fibers more visible. Have
students draw what they see and
relate the fibers to the characteristics of the papers. (Students should
notice that longer fibers are present
in higher quality papers, while short
fibers are present in soft papers such
as tissue.) LS Visual Bio 10C
Teaching Tip
Figure 24 Latex. The milky
sap of certain plants is called
latex. This man is collecting
latex from a rubber tree in
Java, Indonesia.
Wood
After food, wood is the single most valuable resource obtained from
plants. Countless products, such as those shown in Figure 25, are
made from wood. The wood from trees that have been cut down
and sawed into boards is called lumber. Nearly 75 percent of the
lumber cut in the United States is used for building construction.
The rest is used to make products that contain wood, or it is ground
and moistened to make wood pulp. Wood pulp is made into paper,
rayon, and many other products. Finally, for more than a quarter of
the world’s people, wood is still the main source of fuel for heating
and cooking.
Figure 25 Items made with wood
Furniture, buildings, boats, cabinets, and violins
are made from wood.
GENERAL
Products That Come From Trees
Have students make a Graphic
Organizer similar to the one at the
bottom of this page to illustrate
the importance of trees. Ask them
to use the vocabulary words applicable for this section, together with
any other words that they wish
to include. TAKS 3 Bio 13A
520
Graphic Organizer
Use this graphic organizer with
Teaching Tip on this page.
latex
Trees
are used as
pp. 520–521
Student Edition
TAKS Obj 3 Bio 13A
TEKS Bio 13A
TEKS Bio/IPC 3C
Teacher Edition
TAKS Obj 3 Bio 13A
TEKS Bio 13A
TEKS Bio/IPC 1B, 3C
520
produce
which is
used to
make
taxol
medicines
such as
aspirin
produce
fuel
buildings
other
products
Chapter 23 • Introduction to Plants
rubber
which is
used to
make
lumber
which is
ground
into
wood pulp
which is
used to
make
paper
rayon
Figure 26 Sources of medicines
These two common garden plants are the sources of important medicines.
Teach, continued
continued
READING
SKILL
BUILDER
Foxglove, the source of a drug used to treat
cardiac disorders
Rosy periwinkle, the original source of two cancer-fighting drugs
Reading Organizer Have students
keep a list of plants and their uses
as they read this section. When
they have finished reading, have
them make a table of the items in
their list.
Medicines
MEDICINE
People have always used substances obtained from plants to treat a
variety of ailments. By studying the plants traditionally used to treat
human ailments, researchers have developed many “modern”
medicines. For example, solutions made by soaking the bark of
willow trees, Salix, were a traditional cure for aches and pains. The
pain-relieving chemical found in willows is called salicin (SAL uh
sihn). Acetylsalicylic (uh SEET l sal uh SIHL ihk) acid, a derivative of
salicin, was first sold in 1899 under the name “aspirin.” Today,
aspirin is the most widely used pain-relieving drug in the world.
Two familiar garden plants, seen in Figure 26, are important
sources of life-saving medicines. The extremely poisonous leaves of
the foxglove, Digitalis purpurea, yield digitalis (dihj ih TAL ihs), a
drug that is used to stabilize irregular heartbeats and to treat cardiac disorders. The rosy periwinkle, Catharanthus roseus, is the original source of two cancer-treatment drugs—vinblastine (vihn BLAS
teen) and vincristine (vihn KRIHS teen). Vinblastine is often used to
treat Hodgkin’s disease, a type of cancer that affects the lymph
nodes. Vincristine is used to treat childhood leukemia and other
types of cancer. Table 2 contains other examples of medicines that
originally derived from plants.
CONNECTION
The potato plant is a member of
the nightshade family (Solanaceae).
Many plants in this family produce alkaloids that are poisonous
to people and animals. Some
examples are tobacco, which
produces the alkaloid nicotine;
jimson weed and datura, which
produce the alkaloids atropine
and scopolamine, and belladonna,
which also produces atropine.
Atropine and scopolamine are
used to treat muscle spasms. The
belladonna’s name (“beautiful
woman”) refers to the old practice of placing drops of the plant
extract into women’s eyes, which
resulted in dilated pupils. Potato
plants are normally not poisonous, but if the tubers are exposed
to light, they may turn green.
These green portions contain
alkaloids that are harmful in
large quantities.
Table 2 Some Drugs Originally Derived from Plants
Name
Source
www.scilinks.org
Topic: Medicines from
Plants
Keyword: HX4119
Action
Caffeine
Tea leaves
Acts as a stimulant
Codeine
Poppy fruits
Relieves pain
Cortisone
Yam tubers
Relieves symptoms of allergies
Ephedrine
Ephedra stems
Acts as a decongestant
Taxol
Yew tree bark
Reduces the size of cancerous tumors
521
did you know?
Biotech Plants May Help Fight Cancer
Genetic engineering offers hope of introducing
the anticancer proteins found in foods, such
as broccoli, into other fruits and vegetables.
People would have a wider variety of plant
foods to choose from to obtain these proteins.
Those who do not like to eat broccoli and
related plants could get these proteins from
other sources. Bio/IPC 3C
Trends in Textile Fabrication
Friendlier Rayon Rayon is a synthetic fabric
made from chemically altered cellulose fibers,
usually obtained from wood. Clothing, curtains,
upholstery and industrial products are made
from rayon. New research is aimed at making
rayon using a more environmentally friendly
process.
Transparencies
TT Some Drugs Originally Derived
from Plants
Chapter 23 • Introduction to Plants
521
Figure 27 Cotton
Cotton is the plant fiber that is most widely used to make cloth.
Close
Reteaching
Have students work in groups of
three or four. Have each group
answer the following questions
with as many examples as they
can think of: What are the most
important cereal grains? (wheat,
rice, and corn) What are some
other plants used as food sources?
(lentils, soybeans, sugar cane,
cassava, etc.) What are some of the
important products of the timber
industry? (lumber, paper, fuel,
turpentine) what are some medicines derived from plants? (taxol,
codeine, digitalis, ephedrine, etc.)
When groups are finished, have
students share their answers.
Quiz
GENERAL
1. List six plant parts that can
be used as food. (Roots, stems,
flowers, fruits, seeds, and leaves
are all used as food.)
2. True or false: scientists have
identified all of the possible
medicines that can be made
from plants. (False. Not all plants
have been discovered, and there
are chemicals produced by plants
that have never been tested.)
Alternative
Assessment
Cotton bolls that have split open,
revealing cotton fibers
Indian woman spinning cotton into thread that will be woven into cloth
Fibers
Reviewing Information
Prepare flashcards for each
of the Key Terms in this
chapter. On each card, write
the term on one side and its
definition on the other side.
Use the cards to review
meanings of the Key Terms.
If you were to look at this sheet of paper very closely through a magnifying glass, you would see that it is made of many interlocking
fibers. These fibers are strands of cellulose, which is a component of
the cell walls of plants. In plants, fibers help provide support for the
plant body. The strength and flexibility of plant fibers make them
ideal materials for making paper, cloth, and rope. Most of the fibers
used to make paper come from wood. Paper-making fibers are also
obtained from many other plants, including cotton, flax, rice, bamboo, and papyrus (puh PIE ruhs).
For centuries, people have made clothing with cloth made of cotton, the world’s most important plant fiber. As Figure 27 shows,
white fibers fill up the inside of a cotton boll (bohl), the fruit of the
cotton plant. Cotton thread is spun from the fine white fibers, which
grow on cotton seeds. The stems of flax yield softer, more durable
fibers that are used to make linen. More than 30 percent of the
world’s clothing is now made of synthetic fibers, but natural plant
fibers are still prized for their durability and comfort. Sturdy fibers
of hemp and sisal (SIE suhl) plants are used to make rope.
Section 3 Review
Describe several ways in which wood is used.
GENERAL
Assign students to cooperative
groups to prepare a lunch menu
that consists only of plant-derived
foods, utensils, and furniture.
Students should take care to
design a fully nutritional meal.
Provide a library cart of reserved
books selected for your class for
the project. Co-op Learning Bio 11C
and state how each is used.
13A
Name three types of plants that provide fiber
used in clothing.
13A
Critical Thinking Predicting Results Name
the three most important cereal grains and pre12D
dict the results if one of them ceased to exist.
522
TAKS Test Prep Which plant has
nitrogen-fixing bacteria in its roots?
A potato
B wheat
C alfalfa
D corn
13A
522
Answers to Section Review
TAKS 3 Bio 13A
pp. 522–523
Critical Thinking Evaluating Viewpoints
Justify the viewpoint that wood is the most
13A
important nonfood plant product.
List five medicines that are derived from plants,
1. Wood is used for fuel, lumber, furniture, tools
and utensils, paper, rayon and turpentine.
Student Edition
TAKS Obj 3 Bio 13A
TEKS Bio 12D, 13A
Teacher Edition
TAKS Obj 3 Bio 13A
TEKS Bio 11C, 12D
13A
2. Aspirin is used as a pain reliever and antiinflammatory; digitalis is used to treat heart
disorders; vinblastine is used to treat cancer;
codeine is used as a pain reliever; cortisone is
used to treat allergies; ephedrine is used as a
decongestant; and taxol is used to treat
cancer. TAKS 3 Bio 13A
3. cotton, flax, hemp TAKS 3 Bio 13A
4. Wheat, rice, and corn. Students should recognize
that alternative food sources would need to be
Chapter 23 • Introduction to Plants
quickly utilized or massive starvation could
result. Bio 12D
5. Answers will vary, but students should recognize
that wood is used in many ways. TAKS 3 Bio 13A
6.
A. Incorrect. Potatoes have
underground, starchy tubers, but do not contain
nitrogen-fixing bacteria. B. Incorrect. Wheat
needs nitrogen for healthy growth, but it does
not contain nitrogen-fixing bacteria. C. Correct.
Alfalfa and members of the pea family are some
of the plants that contain bacteria in root nodules that fix nitrogen into a form usable by
plants. D. Incorrect. Corn, like all plants, needs
nitrogen for healthy growth, but corn roots do
not contain nitrogen-fixing bacteria. TAKS 3 Bio 13A
Study
CHAPTER HIGHLIGHTS
ZONE
Key Concepts
●
To survive on land, plants must absorb mineral nutrients,
prevent their bodies from drying out, and reproduce without
water to transmit male gametes.
●
Vascular plants have a system of well-developed tissues that
transport water within a plant. The nonvascular plants lack a
vascular system.• The Science TAKS Prep Appendix in
●
Seeds protect andthis
nourish
a plant’s
embryo,bioldisperse
book provides
integrated
andthe
IPC growth
TAKS practice
the offspring, andogy
delay
of the embryo until
conditions are favorable.
FlowersTAKS
make
reproduction more
• The Holt Science
Practice
efficient by promoting
pollination.
Workbook
provides a review of
●
biology,
chemistry,
physics
The sporophytes of
vascular
plantsand
have
a vascular system.
concepts
on the grades
10 and an underTheir bodies consist
of an tested
aboveground
shoot
and
11
science
TAKS.
ground root.
GENERAL
Have students use the information
in Chapter 23 to design a procedure
for a question-and-answer game.
Students may choose to model
their game after a television game
show or a trivia-type board game.
Encourage students to write
questions that vary in difficulty.
Section 1
1 Adaptations of Plants
cuticle (502)
stoma (502)
guard cell (503)
vascular system (504)
nonvascular plant (504)
vascular plant (504)
seed (504)
embryo (504)
seed plant (504)
flower (505)
phloem (507)
xylem (507)
shoot (507)
root (507)
meristem (507)
Section 2
2 Kinds of Plants
●
Alternative
Assessment
Key Terms
Chapter Resource File
Nonvascular plants are small and lack vascular tissue.
Mosses, liverworts,
and hornworts
are nonvascular
plants.
GENERAL
• Science
Skills Worksheet
●
Seedless vascular plants produce spores with thickened
• Critical Thinking Worksheet
walls that prevent them from drying out. Ferns, club mosses,
GENERAL vascular plants.
Test Prep
Pretest
horsetails, and •whisk
ferns
are seedless
●
Chapter
Test GENERAL
Gymnosperms •are
seed plants
that produce cones. Conifers,
cycads, ginkgoes, and gnetophytes are gymnosperms.
●
Angiosperms are seed plants that produce flowers and fruits.
The angiosperms are classified as either monocots or dicots.
rhizoid (508)
rhizome (510)
frond (511)
cone (511)
gymnosperm (512)
angiosperm (514)
fruit (514)
endosperm (514)
monocot (515)
dicot (515)
Section 3
3 Plants In Our Lives
vegetative part (516)
cereal (518)
grain (518)
●
All types of plant parts—roots, stems, leaves, flowers, fruits,
and seeds—provide food for humans. Rice, corn, and wheat
are cereal grasses and are our most important sources
of food.
●
Wood is a source of wood pulp used for making paper,
lumber used for building materials, and fuel.
●
Many important medicines are currently made from plants
or were originally derived from plants.
●
Plant fibers are used to make paper, cloth, and rope. The
most important sources of plant fibers are wood and cotton.
523
Plants
Answer to Concept Map
The following is one possible answer to
Performance Zone item 15.
may be
vascular plants
nonvascular plants
have
include
lack
vascular tissues
angiosperms
gymnosperms
have
have
flowers
seeds
include
dicots
monocots
include
liverworts
mosses
include
ferns
gnetophytes
cycads
ginkgo
lack
conifers
have
seeds
cones
Chapter 23 • Introduction to Plants
523
Performance
ZONE
CHAPTER 23
ANSWERS
Using Key Terms
1. b TAKS 3 Bio 13A
2. a Bio 13B
3. b TAKS 2 Bio 6D
4. d TAKS 2 Bio 6D; TAKS 3 Bio 13A
5. a. Xylem is water-transporting
tissue; phloem is a tissue that
transports sugars and other
organic molecules.
b. A shoot is the above ground
part of a plant; a root is the
below ground part of a plant.
c. A rhizoid is a root-like
structure that anchors a
plant; a rhizome is an underground stem.
d. A seed contains an embryo,
a seed coat, and stored food;
a fruit contains part of the
flower (ovary) and seeds.
Understanding Key Ideas
6. a TAKS 3 Bio 13A
7. c Bio 10C, 13B
8. d Bio 13B
9. a Bio 13B
10. c
11. b
12. The seeds would likely be
dispersed by becoming attached
to the fur of a mammal and
being transported as the mammal
moves around. Bio 10A, 13B
13. Answers may vary. Vegetarian
diets should contain grains and
legumes, as well as sources of
vitamins B-12 and D such as dairy
products, fortified foods, and
vitamin supplements. Bio 11C
14. Meiosis involves two divisions of
the nucleus, which reduces the
number of chromosomes in a cell
and produces four haploid cells;
in plants the cells that result
directly from meiotic division
are called spores. Bio 6E
Review and Assess
TAKS 1 Bio/IPC 2A, 2D
TAKS 2 Bio 6D
TAKS 3 Bio 7B, 13A
TEKS Bio 3D, 3E, 6D, 6E, 7B, 10C,
11C, 13A, 13B; Bio/IPC 2A, 2D
524
CHAPTER REVIEW
Using Key Terms
1. What structure made it possible for plants
to prevent water loss and to spread
13A
on land?
a. mycorrhizae
c. pollen
b. cuticle
d. seed
11. Drugs derived from the rosy periwinkle are
used in the treatment of
13A
a. heart disease.
c. allergies.
b. leukemia.
d. headaches.
13B
c. zygospore.
d. epiphyte.
3. Which of the following are not seedless
vascular plants?
a. horsetails
b. gymnosperms
12. Look at the cocklebur in the photograph
below. It is a fruit that contains the seeds of
a cocklebur plant. Suggest how this plant’s
10A 13B
seeds might be dispersed.
6D
c. ferns
d. club mosses
4. Which of the following is not a source of
fibers for both paper and cloth?
a. flax
c. wood
b. cotton
d. sisal
6D 13A
5. For each pair of terms, explain the differ-
ences in their meanings.
a. xylem, phloem
c. rhizoid, rhizome
b. shoot, root
d. seed, fruit
Understanding Key Ideas
6. Seeds helped plants adapt to life on
land by
10C 13A
a. providing nourishment for embryos.
b. protecting embryos from air pollution.
c. sprouting during unfavorable weather.
d. limiting the dispersal of plant offspring.
7. Which of the following is not a characteristic
10C 13B
of vascular plants?
a. xylem and phloem
b. stems and leaves
c. a dominant gametophyte
d. a diploid sporophyte
8. Unlike angiosperms, gymnosperms
13B
a. are pollinated by wind.
b. do not have seeds.
c. have a diploid sporophyte generation.
d. do not bear fruit.
13.
A friend is concerned that
your vegetarian diet is not healthy. Make a
list of the measures you would take to
ensure that your diet will provide you with
all the nutrients you need.
11C
14. How does meiosis result in the production
of haploid spores? (Hint: See Chapter 7,
Section 1.)
6E
15.
Concept Mapping Make a concept
map that shows how plants are classified.
Include the following terms in your map:
vascular plants, nonvascular plants, ferns,
angiosperms, gymnosperms, mosses, cones,
vascular tissue, seeds, and flowers.
3E
524
15. One Possible answer to the concept map is
found at the bottom of the Study Zone page.
Bio 3E
Critical Thinking
16. The sporophytes are large and have many
leaves that can intercept light from the sun.
A vascular system enables the sporophytes
to grow very large by distributing water and
nutrients efficiently. Their reproductive cells
(eggs and sperm) are produce near the tops of
the sporophyte, where they can readily be
dispersed by wind or animals. TAKS 3 Bio 7B
Chapter 23 • Introduction to Plants
13B
10. The most important sources of food are
a. legumes.
c. cereal grains.
b. root crops.
d. vegetables.
2. Plant life cycles include a diploid individual
that is called a(n)
a. sporophyte.
b. gametophyte.
9. Which of the following are not dicots?
a. grass family
c. mustard family
b. rose family
d. legume family
Assignment Guide
Section
1
2
3
Questions
1–2, 5a–c, 6, 14, 16–17
3, 5d, 7–9, 12, 15
4, 10–11, 13, 18–22
13A