22.1 What Is a Plant?

Key Questions

  • What do plants need to survive?

  • How did plants adapt to life on land?

  • What feature defines most plant life cycles?

Vocabulary

alternation of generations • sporophyte • gametophyte

Taking Notes

Preview Visuals Preview Figure 22–4 and list five main groups of plants. For each group, list any characteristics or specific examples that you already know.

THINK ABOUT IT What color is life? Living things can be just about any color, of course. But imagine yourself in a place so abundant with life that living things actually blot out the sun. Now what color do you see? If you've imagined a thick forest or a teeming jungle, then just one color will fill the landscape of your mind: green—the color of plants. Plants have adapted so well to so many environments that they dominate much of the surface of our planet.

Characteristics of Plants

What do plants need to survive?

What are plants? You are already familiar with many examples, such as trees, shrubs, and grasses. But did you know that mosses and ferns are also types of plants? In the last several years, biologists have reclassified green algae as plants, too. (Green algae used to be considered protists.) What characteristics do all these organisms share?

The Plant Kingdom Traditionally, plants are classified as members of the kingdom Plantae. Plants are eukaryotes that have cell walls containing cellulose and carry out photosynthesis using chlorophyll a and b. While most plants are autotrophs, a few are parasites or saprobes.

A garden of green plants and four people working in the garden. There is an inset diagram of a plant cell showing a cell wall and green colored chloroplast inside cell the wall.

FIGURE 22–1 Diagram of a Plant Cell Plant leaves appear green due to the photosynthetic pigments chlorophyll a and b, which are located in chloroplasts.

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Table of Contents

Miller & Levine Biology
About the Authors
Changing the World of Biology Education
Contents
Diversity of Life: A Visual Guide DOL•1–DOL•64
Labs and Activities
Features
UNIT 1 The Nature of Life
1 The Science of Biology
2 The Chemistry of Life
Unit Project
UNIT 2 Ecology
3 The Biosphere
4 Ecosystems and Communities
5 Populations
6 Humans in the Biosphere
Unit Project
UNIT 3 Cells
7 Cell Structure and Function
8 Photosynthesis
9 Cellular Respiration and Fermentation
10 Cell Growth and Division
Unit Project
UNIT 4 Genetics
11 Introduction to Genetics
12 DNA
13 RNA and Protein Synthesis
14 Human Heredity
15 Genetic Engineering
Unit Project
UNIT 5 Evolution
16 Darwin's Theory of Evolution
17 Evolution of Populations
18 Classification
19 History of Life
Unit Project
UNIT 6 From Microorganisms to Plants
20 Viruses and Prokaryotes
21 Protists and Fungi
22 Introduction to Plants
23 Plant Structure and Function
24 Plant Reproduction and Response
Unit Project
UNIT 7 Animals
25 Introduction to Animals
26 Animal Evolution and Diversity
27 Animal Systems I
28 Animal Systems II
29 Animal Behavior
Unit Project
UNIT 8 The Human Body
30 Digestive and Excretory Systems
31 Nervous System
32 Skeletal, Muscular, and Integumentary Systems
33 Circulatory and Respiratory Systems
34 Endocrine and Reproductive Systems
35 Immune System and Disease
Unit Project
A Visual Guide to The Diversity of Life
HOW TO USE THIS GUIDE
THE TREE OF LIFE
Bacteria
Protists
Fungi
Plants
Animals
Appendices
Appendix A Science Skills
Appendix B Lab Skills
Appendix C Technology & Design
Appendix D Math Skills
Appendix E Periodic Table
Glossary
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q, R
S
T
U
V
W
X, Y, Z
Index
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
Credits
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