Essentials of Biology
for my children...
Sylvia S. Mader
ESSENTIALS OF BIOLOGY
Published by McGraw-Hill, a business unit of The McGraw-Hill Companies, Inc., 1221 Avenue of the Americas, 
New York, NY 10020. Copyright © 2007 by The McGraw-Hill Companies, Inc. All rights reserved. No part of 
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Some ancillaries, including electronic and print components, may not be available to customers outside the United 
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 This book is printed on recycled, acid-free paper containing 10% postconsumer waste.

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ISBN-13 978–0–07–288616–0
ISBN-10 0–07–288616–1

Publisher: Janice Roerig-Blong
Sponsoring Editor: Thomas C. Lyon 
Director of Development: Kristine Tibbetts
Senior Developmental Editor: Margaret B. Horn
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Designer: Rick D. Noel 
Cover/Interior Designer: Christopher Reese
(USE) Cover Image: ©Getty Images, Red-eyed Tree Frog and Morpho Butterfly, # 10081947
Senior Photo Research Coordinator: Lori Hancock
Photo Research: Connie Mueller
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Compositor: Precision Graphics
Typeface: 10/12 Times
Printer: Von Hoffmann Corporation
The credits section for this book begins on page 623 and is considered an extension of the copyright page.
	Library of Congress Cataloging-in-Publication Data

Mader, Sylvia S.
 Essentials of biology / Sylvia S. Mader. —– 1st ed.
	p.	cm.
 Includes bibliographical references and index.
 ISBN 978–0–07–288616–0 — 0–07–288616–1 
 1. Biology. I. Title.

 QH308.2.M24 2007
 570—dc22			2005051119
				CIP
www.mhhe.com

	Contents
Part VIIEcology
Part VIAnimal Structure and Function
Part VPlant Structure and Function
Part IVDiversity of Life
Part IIIEvolution
Part IIGenetics
	Acknowledgments
	Teaching Supplements	

Learning Supplements
For the Student
Student Study Guide
Dr. Sylvia Mader has written the Student Study Guide that accompanies Essentials of Biology, thereby ensuring close coordination with the text. Each text chapter has a corresponding study guide chapter that includes a chapter review, a review of the key terms in the chapter, study exercises and questions for each section of the chapter, and a chapter test. Answers to all questions are provided to give students immediate feedback. Students who make use of the Student Study Guide should find that performance increases dramatically. 
ISBN-13: 978-0-07-321774-1 (ISBN-10: 0-07-321774-3)
ARIS 
McGraw-Hill’s ARIS—Assessment, Review, and Instruction System—for Essentials of Biology at www.mhhe.com/maderessentials offers access to a vast array of premium online content to fortify the learning experience.
Student Edition
The Student Edition of ARIS features a wide variety of tools to help students learn biological concepts and to reinforce their knowledge:
Online study aids are organized according to the major sections of each chapter. Practice quizzes, interactive activities, labeling exercises, flashcards, and much more will complement the learning and understanding of biology
Essential Study PartnerThis collection of interactive study modules contains hundreds of animations, learning activities, and quizzes designed to help students grasp complex concepts.
AnimationsFull-color presentations of key biological processes have been brought to life via animation. You can pause, rewind, fast-forward, and turn the audio on or off. Many of the animations are also available with Spanish narration and audio.
Animation QuizzesQuizzes based on the new animations help you assess your understanding of the concepts.
Online TutoringThe tutorial service is moderated by qualified instructors. Help with difficult concepts is only an email away!
Student Interactive Cd-rom
This interactive CD-ROM is an indispensable resource for studying topics covered in the text. It includes chapter outlines, chapter-based quizzes, animations of complex processes, flashcards, PowerPoint® lecture outlines, and PowerPoint® slides of all art and photos found in the textbook. All of the material is organized chapter-by-chapter. Direct links to the text’s ARIS website and to the Essential Study Partner are also provided.
ISBN-13: 978-0-07-321775-8 (ISBN-10: 0-07-321775-1)
For the Instructor
McGraw-Hill offers a variety of tools and technology products to support Essentials of Biology. Instructors can obtain teaching aids by calling the Customer Service Department at (800) 338-3987 or by contacting their local McGraw-Hill sales representative.
Essentials of Biology Laboratory Manual
The Essentials of Biology Laboratory Manual is written by Dr. Sylvia Mader. With few exceptions, each chapter in the text has an accompanying laboratory exercise in the manual. Every laboratory has been written to help students learn the fundamental concepts of biology and the specific content of the chapter to which the lab relates, as well as gain a better understanding of the scientific method. 
ISBN-13: 978-0-07-340341-0 (ISBN-10: 0-07-340341-5)
Digital Content Manager
This collection of multimedia resources provides tools for rich visual support of your lectures. You can utilize artwork from the text in multiple formats to create customized classroom presentations, visually based tests and quizzes, dynamic course website content, or attractive printed support materials. The following digital assets are available either on a cross-platform CD-ROM or on a DVD and are grouped by chapters:
Art Libraries. Full-color digital files of all illustrations in the book, plus the same art saved in unlabeled and gray scale version, can be readily incorporated into lecture presentations, exams, or custom-made classroom materials.
Photos Library. All photos from the text are available in digital format. 
Active Art Library. Illustrations depicting key processes have been converted to a format that allows the artwork to be edited inside of PowerPoint. Each piece can be broken down to its core elements, grouped or ungrouped, and edited to create customized illustrations.
Animations Library. The next generation of biology animations is now available! New animations bring key processes to life and offer total flexibility. Designed to be used in lectures, you can pause, rewind, fast-forward, and turn the audio on or off to create dynamic lecture presentations. Many of the animations are also available with Spanish narration and audio. 
Tables Library. Every table that appears in the text is provided in electronic format.
Additional Photos Library. Over 700 photos not found in Essentials of Biology are available for use in creating lecture presentations.
PowerPoint Lecture Outlines. A ready-made presentation that combines lecture notes and illustrations is written for each chapter. They can be used as they are, or the instructor can customize them to preferred lecture topics and organization.
PowerPoint Art Slides. Art, photos, and tables from each chapter have been pre-inserted into blank PowerPoint slides to which you can add your own notes.
CD-ROM ISBN-13: 978-0-07-297442-3 (ISBN-10: 0-07-297442-7)
DVD ISBN-13: 978-0-07-326194-2 (ISBN-10: 0-07-326194-7)
Instructor’s Testing and Resource 
CD-ROM
This cross-platform CD-ROM provides these resources for the instructor:
Instructor’s Manual contains learning objectives, extended lecture outlines, lecture enrichment and student activities suggestions, and critical thinking questions. In addition, there is an explanation of text changes and reorganization as well as information on new and revised illustrations and tables.
Test Bank offers questions that can be used for homework assignments or the preparation of exams.
Computerized Test Bank utilizes testing software to quickly create customized exams. This user-friendly program allows instructors to sort questions by format or level of difficulty; edit existing questions or add new ones; and scramble questions and answer keys for multiple versions of the same test.
CPS Question Bank for use with the eInstruction Classroom Performance System is included on this CD-ROM.
ISBN-13: 978-0-07-297444-7 (ISBN-10: 0-07-297444-3)
eInstruction Classroom Performance System (Cps)
Wireless technology brings interactivity into the classroom or lecture hall. Instructors and students receive immediate feedback through wireless response pads that are easy to use and engage students. eInstruction can be used by instructors to: 
	•	Take attendance
	•	Administer quizzes and tests
	•	Create a lecture with intermittent questions
	•	
Manage lectures and student comprehension through use of the CPS grade book
	•	
Integrate interactivity into their PowerPoint presentations
Transparencies
This set of overhead transparencies includes every piece of line art in the textbook plus every table. The images are printed with better visibility and contrast than ever before, and labels are large and bold for clear projection.
ISBN-13: 978-0-07-297441-6 (ISBN-10: 0-07-297441-9)
ARIS 
McGraw-Hill’s ARIS—Assessment, Review, and Instruction System—for Essentials of Biology is a complete online tutorial, electronic homework, and course management system designed for greater ease of use than any other system available. Free with adoption of McGraw-Hill’s Essentials of Biology text, instructors can create and share course materials and assignments with colleagues with a few clicks of the mouse. All PowerPoint lectures, assignments, quizzes, tutorials, and interactives are directly tied to text-specific materials in Essentials of Biology, but instructors can also edit questions, import their own content, and create announcements and due dates for assignments. ARIS has automatic grading and reporting of easy-to-assign homework, quizzing, and testing. All student activity within McGraw-Hill’s ARIS is automatically recorded and available to the instructor through a fully integrated grade book that can be downloaded to Excel.
The Essentials of Biology ARIS site at www.mhhe.com/
maderessentials offers access to a vast array of premium online content to fortify the learning and teaching experience for students and instructors.
Instructor Edition
In addition to all of the resources for students, the Instructor Edition of the Online Learning Center has these assets:
	•	
eInstruction Classroom Performance System (CPS) Question Bank A set of questions for use with the CPS is provided for every textbook chapter to assist instructors in quickly assessing student comprehension of the concepts.
	•	
Animations The next generation of biology animations is available with Essentials of Biology. Full-color presentations of key biological processes have been brought to life via animation. These animations offer flexibility for instructors. Designed to be used in lectures, you can pause, rewind, fast-forward, and turn the audio on or off. Many of the animations are also available with Spanish narration and audio.
	•	
Laboratory Resource Guide This preparation guide provides set-up instructions, sources for materials and supplies, time estimates, special requirements, and suggested answers to all questions in the Essentials of Biology Laboratory Manual.
	•	
PageOut McGraw-Hill’s exclusive tool for creating your own website for your general biology course. It requires no knowledge of coding and is hosted by McGraw-Hill.
	•	
Active Art Demo Teaches you how to use the Active Art that is on the Digital Content Manager CD-ROM.
	•	
Case Studies Offers suggestions on how to use Case Studies in your classroom.
McGraw-Hill: Biology Digitized 
Video Clips
McGraw-Hill is pleased to offer adopting instructors a new presentation tool—digitized biology video clips on DVD! Licensed from some of the highest-quality science video producers in the world, these brief segments range from about five seconds to just under three minutes in length and cover all areas of general biology from cells to ecosystems. Engaging and informative, McGraw-Hill’s digitized biology video clips will help capture students’ interest while illustrating key biological concepts and processes such as mitosis, how cilia and flagella work, and how some plants have evolved into carnivores.
ISBN-13: 978-0-07-312155-0 (ISBN-10: 0-07-312155-X)
Mader Micrograph Slides
This set contains one hundred 35mm slides of many of the photomicrographs and electron micrographs in the text.
ISBN-13: 978-0-07-239977-6 (ISBN-10: 0-07-239977-5)
Part IThe Cell
Is it possible to engage students while introducing the principles of biology within the time span of one semester? Essentials of Biology is the text that meets the challenge! 
My goal in writing Essentials of Biology was twofold: to explain the principles of biology clearly and to illustrate them in a captivating, easy-to-understand manner. Essentials of Biology is traditional in its approach, organized around the major concepts of biology—the theory of evolution, the cell theory, the gene theory, the theory of homeostasis, and the theory of ecosystems. However, adopters will notice from the outset a decided effort to reach out to today’s student. The design and illustration program of the book is appropriate for those who are accustomed to being visually stimulated. The writing style is conversational and inviting in its tone. In short, this book offers the essence of biology without the amount of detail found in other introductory biology texts. Even though this book is succinct, it retains the hallmark features of a Mader book: clear writing, well-developed visuals, a great pedagogical system, and logical organization of chapters.
Because biology is now characterized by new revelations almost daily, it is sometimes difficult to decide what to include in a text. While it is tempting to concentrate on the new, it remains clear that today’s students need a good foundation in the basics, just as previous students did. Essentials of Biology stresses the principles of biology but uses pertinent applications to increase appreciation and to show that biology is a science relevant to everyday life. Genetics comes alive in Chapter 13, which shows how both Mendelian and molecular genetics can be used to counsel clients about how genetic disorders can be detected, controlled, and/or treated. Chapter 25, a nutrition chapter, shows students how the knowledge of chemistry is beneficial when making dietary decisions to achieve the proper weight and remain healthy. Stem cell research, human diseases, and reproductive choices, all topics of interest to students, are also included. Environmental concerns are addressed, and Chapter 32 concentrates on how human activities impact the biosphere.
An Overview of the Text
The introductory chapter provides students with a preview of biological principles before they take up individual topics. Included are the characteristics of life, an overview of life’s diversity, and a discussion of the scientific process.
Part I The Cell
In this part students are introduced to a bit of chemistry before considering the anatomy and physiology of the cell. Cells, like organisms, must acquire and use matter and energy in order to maintain their existence.
Part II Genetics
DNA, the composition of genes, is passed on during cellular and organismal reproduction. Patterns of inheritance are pertinent, but today, the treatment of genetic disorders and cancer is dependent upon molecular genetics. With the sequencing of the human genome, new ways are being found to expand the field of medicine. 
Part III Evolution
Biology cannot be understood without a knowledge of evolution. This part begins with a chapter that explains the main points of Darwin’s theory and examines the variety of evidence that supports evolution. The mechanisms necessary to microevolution and macroevolution are then considered before the history of life on Earth is reviewed.
Part IV Diversity of Life
The major categories of life are presented and their possible relationships are explored. Students need to be aware of the variety of life with which we share this planet. An evolutionary tree for plants and another for animals become icons for appropriate chapters.
Part V Plant Structure and Function
These chapters instill in the students an appreciation of botany. The flowering plant is used as the representative organism to study the basics of plant anatomy. 
Part VI Animal Structure and Function 
A comparative theme, which uses the human animal as the representative organism, runs through this part. The emphasis is on homeostasis, which is introduced and explored in Chapter 22.
Part VII Ecology
This part moves from population dynamics through the interactions of populations in communities and ecosystems. The last chapter shows how human activities stress the biosphere and gives reasons why biodiversity should be preserved.
Sylvester Allred
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Daytona Beach Community College
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LaGuardia Community College
Sirakaya Beatrice
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East Central University
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Ragupathy Kannan
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University of Louisville
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Orange Coast College
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California State University—Sacramento
Scott L. Kight
Montclair State University
Kristin Lenertz
Black Hawk College
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California State University—Sacramento
Michelle Malott
Minnesota State University— Moorhead
Paul Mangum
Midland College
Mara Manis
Hillsborough Community College
Karen Benn Marshall
Montgomery College— Takoma Park
Cynthia Conaway Mauroidis
Northwest State Community College
Elizabeth McPartlan
De Anza College
Dwight Meyer
Queensborough Community College
Rod Nelson
University of Arkansas—Fort Smith
Donald J. Padgett
Bridgewater State College
Tricia L. Paramore
Hutchinson Community College
Brian K. Paulson
California University of Pennsylvania
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Northern Kentucky University
Lisa Rapp
Springfield Technical Community College
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Glendale Community College
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Washington State University
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Lorain County Community College
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University of South Carolina
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Garland Rudolph Upchurch, Jr.
Texas State University, San Marcos
James A. Wallis II
St. Petersburg College, Tarpon Springs Campus
Cosima B. Wiese
College Misericordia
Melissa Zwick 
Longwood University
I am also grateful to the following who made significant contributions to Essentials of Biology.
Nancy Butler
Kutztown University of Pennsylvania
Stephen D. Ebbs
Southern Illinois University
Lynn Firestone
Brigham Young University—Idaho
Patrick Galliart
Northern Illinois University
Shelley Jansky
University of Wisconsin—Madison
Kimberly Lyle-Ippolito
Anderson University
Cherie McKeever
Montana State University College of Technology—Great Falls
Donna H. Mueller
Drexel University
Kathleen Pelkki
Saginaw Valley State University
Wendy Schiff
St. Louis Community College—Meramec
Kent Thomas
Wichita State University
Wendy Vermillion
Columbus State Community College
Jennifer Warner
University of North Carolina—Charlotte
Nicole Welch
Middle Tennessee State University
Acknowledgments
Many dedicated and talented individuals assisted in the development of Essentials of Biology. I am very grateful for the help of so many professionals at McGraw-Hill who were involved in bringing this book to fruition. In particular, let me thank Margaret Horn, the developmental editor who lent her talents and advice to all those who worked on this text. The biology editor was Thomas Lyon, who steadfastly encouraged and supported this project. The project manager, Jayne Klein, faithfully and carefully steered the book through the publication process. Tamara Maury, the marketing manager, tirelessly promoted the text and educated the sales reps on its message
The design of the book is the result of the creative talents of Rick Noel and many others who assisted in deciding the appearance of each element in the text. Precision Graphics followed their guidelines as they created and reworked each illustration, emphasizing pedagogy and beauty to arrive at the best presentation on the page. Lori Hancock and Connie Mueller did a superb job of finding just the right photographs and micrographs.
My staff, consisting of Evelyn Jo Hebert and Beth Butler, worked faithfully as they helped proof the chapters and made sure all was well before the book went to press. As always, my family was extremely patient with me as I remained determined to meet every deadline on the road to publication. My husband, Arthur Cohen, is also a teacher of biology. The many discussions we have about the minutest detail to the gravest concept are invaluable to me.
I am very much indebted to the following reviewers whose suggestions and expertise were so valuable as I developed Essentials of Biology.

Prefacexiii
Acknowledgmentsxiv
Teaching Supplements for the Instructorxvi
Learning Supplements for the Studentxviii
Guided Tourxx
The Learning Systemxxiv
Chapter 1
A View of Life1
1.1		The Unity and Diversity of Life 2
Living Things Are Organized2
Living Things Acquire Materials and Energy3
Living Things Respond3
Living Things Reproduce and Develop3
Living Things Have Adaptations4
1.2		How the Biosphere Is Organized5
Ecosystem5
Biosphere5
1.3		How Organisms Are Classified6
Categories of Classification6
Biodiversity7
1.4		Science As a Way of Knowing8
Observation8
Hypothesis8
Experiments/Further Observations8
Conclusion9
Scientific Theory9
Example of a Controlled Study10
1.5		Science and Society12

Chapter 2
The Chemical Basis of Life15
2.1		The Nature of Matter16
Atomic Structure17
The Periodic Table17
Arrangement of Electrons in an Atom 18
Types of Chemical Bonds19
Chemical Reactions 21
2.2		Water’s Importance to Life22
The Structure of Water22
Properties of Water 22
Acids and Bases25
Chapter 3
The Organic Molecules 
of Life29
3.1		Organic Molecules30
The Carbon Atom30
The Carbon Skeleton and Functional Groups 31
3.2		The Organic Molecules of Cells32
Carbohydrates33
Lipids35
Proteins38
Nucleic Acids41
Chapter 4
Inside the Cell47
4.1		Cells Under the Microscope48
4.2		The Two Main Types of Cells50
Prokaryotic Cells50
4.3		The Plasma Membrane 52
Functions of Membrane Proteins53
4.4		Eukaryotic Cells54
Nucleus and Ribosomes56
Endomembrane System58
Vacuoles59
Energy-Related Organelles60
The Cytoskeleton 62
Centrioles62
Cilia and Flagella63
4.5		Outside the Eukaryotic Cell64
Plant Cell Walls64
Cell Surfaces in Animals64
Chapter 5
The Dynamic Cell69
5.1		What Is Energy? 70
Measuring Energy70
Two Energy Laws70
5.2		ATP: Energy for Cells72
Structure of ATP72
Use and Production of ATP72
The Flow of Energy74
5.3		Metabolic Pathways and Enzymes75
Energy of Activation75
An Enzyme’s Active Site76
5.4		Cell Transport77
Passive Transport: No Energy Required 77
Active Transport: Energy Required78
Bulk Transport79
Chapter 6
Energy for Life83
6.1		Overview of Photosynthesis84
Flowering Plants as Photosynthesizers85
The Photosynthetic Process86
6.2		Light Reactions87
Photosynthetic Pigments87
The Electron Pathway of the Light Reactions88
Organization of the Thylakoid Membrane89
6.3		Calvin Cycle Reactions90
Fixation of Carbon Dioxide90
Reduction of Carbon Dioxide90
Regeneration of RuBP 91
The Importance of the Calvin Cycle91
6.4		Other Types of Photosynthesis92
C4 Photosynthesis 92
CAM Photosynthesis93
Evolutionary Trends93
Chapter 7
Energy for Cells97
7.1		Cellular Respiration98
Phases of Complete Glucose Breakdown99
7.2		Outside the Mitochondria: Glycolysis101
Energy-Investment Steps101
Energy-Harvesting Steps101
7.3		Inside the Mitochondria102
Preparatory Reaction 102
The Citric Acid Cycle102
The Electron Transport Chain104
Energy Yield from Glucose Metabolism106
Alternative Metabolic Pathways106
7.4		Fermentation107
Microorganisms and Fermentation107

Chapter 8
Cellular Reproduction111
8.1		The Basics of Cellular Reproduction112
Chromosomes113
Chromatin to Chromosomes113
8.2		The Cell Cycle114
Interphase114
M (Mitotic) Stage114
8.3		Mitosis and Cytokinesis115
The Spindle 115
Phases of Mitosis in Animal Cells116
Cytokinesis in Animal and Plant Cells118
8.4		The Cell Cycle Control System 119
Cell Cycle Checkpoints119
Internal and External Signals119
Apoptosis120
8.5		The Cell Cycle and Cancer121
Characteristics of Cancer Cells121
Cancer Treatment122
Prevention of Cancer122
Chapter 9
Sexual Reproduction127
9.1		The Basics of Meiosis128
The Human Life Cycle129
Overview of Meiosis130
9.2		The Phases of Meiosis132
The First Division—Meiosis I132
The Second Division—Meiosis II133
9.3		Meiosis Compared to Mitosis134
Process134
Occurrence134
9.4		Abnormal Chromosome Inheritance136
Down Syndrome136
Abnormal Sex Chromosome Number137
Chapter 10
Patterns of Inheritance141
10.1		Mendel’s Laws142
Mendel’s Experimental Procedure143
One-Trait Inheritance144
Two-Trait Inheritance146
Mendel’s Laws and Probability147
Mendel’s Laws and Meiosis148
10.2		Beyond Mendel’s Laws149
Incomplete Dominance 149
Multiple-Allele Traits149
Polygenic Inheritance150
Environment and the Phenotype150
Pleiotropy151
10.3		Sex-Linked Inheritance152
X-Linked Alleles152
An X-Linked Problem153
10.4		Inheritance of Linked Genes154
Constructing a Chromosome Map154
Chapter 11
DNA Biology and Technology159
11.1		DNA and RNA Structure and Function160
Structure of DNA160
Replication of DNA164
RNA Structure and Function 164
11.2		Gene Expression166
Structure and Function of Proteins166
From DNA to RNA to Protein166
Review of Gene Expression171
Genes and Gene Mutations172
11.3		DNA Technology173
Recombinant DNA Technology173
Polymerase Chain Reaction174
Applications174
Chapter 12
Gene Regulation and Cancer179
12.1		Control of Gene Expression180
Reproductive and Therapeutic 
Cloning 180
Levels of Gene Expression Control182
12.2		Cancer: A Failure of Genetic Control188
Proto-Oncogenes and Tumor Suppressor Genes189
Other Genetic Changes190
Hereditary Forms of Cancer191
Chapter 13
Genetic Counseling195
13.1		Counseling for Chromosomal Disorders196
Karyotyping196
Chromosomal Mutations198
13.2		Counseling for Genetic Disorders: 
The Present200
Family Pedigrees200
Genetic Disorders of Interest202
Testing for Genetic Disorders205
13.3		Counseling for Genetic Disorders: 
The Future208
Sequencing the Bases of the Human Genome208
Genetic Profiling 209
13.4		Gene Therapy210
Ex Vivo Gene Therapy210
In Vivo Gene Therapy210

Chapter 14
Darwin and Evolution215
14.1		Darwin’s Theory of Evolution216
Before Darwin217
Darwin’s Conclusions219
Natural Selection and Adaptation221
Darwin and Wallace223
14.2		Evidence for Evolution224
Fossil Evidence224
Biogeographical Evidence225
Anatomical Evidence226
Biochemical Evidence227
Chapter 15
Evolution on a Small Scale231
15.1		Microevolution 232
Evolution in a Genetic Context233
Causes of 
Microevolution235
15.2		Natural Selection238
Types of Selection238
Maintenance 
of Variations240
Chapter 16
Evolution on a Large Scale245
16.1		Macroevolution246
Defining Species246
Models of Speciation250
16.2		The History of Species253
The Geological Timescale253
The Pace of Speciation 253
Mass Extinctions of Species 254
16.3		Classification of Species 256
Classification and Phylogeny256
Cladistic Systematics259
Classification Systems261

Chapter 17
The First Forms of Life265
17.1		The Viruses 266
Viral Reproduction266
Plant Viruses 268
Animal Viruses 268
17.2		Viroids and Prions270
17.3		The Prokaryotes270
Bacteria270
Archaea275
17.4		The Protists276
General Biology of Protists276 
Chapter 18
Land Environment: Plants 
and Fungi283
18.1		Onto Land284
Alternation of Generations 286
18.2		Diversity of Plants287
Nonvascular Plants287
Vascular Plants288
Gymnosperms291
Angiosperms292
Economic Benefits of Plants295
Ecological Benefits of Plants295
18.3		The Fungi296
General Biology of a Fungus296
Ecological Benefits of Fungi298
Economic Benefits of Fungi300
Fungi as Disease-Causing Organisms300
Chapter 19
Both Water and Land: Animals305
19.1		Evolution of Animals 306
The Evolutionary History of Animals307
The Evolutionary Tree of Animals308
19.2		Introducing the Invertebrates 310
Sponges: Multicellularity310
Cnidarians: True Tissues310
Flatworms: Bilateral Symmetry311
Roundworms: Pseudocoelomates 312
19.3		Protostomes and Deuterostomes Compared313
19.4		Molluscs, Annelids, and Arthropods314
Molluscs314
Annelids: Segmented Worms 315
Arthropods: Jointed Appendages316
19.5		Echinoderms and Chordates319
Echinoderms319
Chordates320
Fishes: First Jaws and Lungs322
Amphibians: Jointed Vertebrate Limbs323
Reptiles: Amniotic Egg 324
Birds: Feathers324
Mammals: Hair and Mammary Glands326
19.6		Human Evolution328
Evolution of Hominids329
Evolution of Modern Humans331

Chapter 20
Plant Anatomy and Growth337
20.1		Plant Organs338
Leaves338
Stems339
Roots339
Monocot Versus Eudicot Plants340
20.2		Plant Tissues and Cells341
Epidermis and Ground Tissue341
Vascular Tissue342
20.3 		Organization of Leaves342
20.4 		Organization of Stems344
Nonwoody Stems344
Woody Stems345
20.5		Organization of Roots347
Tissues of a Eudicot Root347
Organization of Monocot Roots347
Comparison with Stems347
20.6		Plant Nutrition348
Adaptations of Roots for Mineral Uptake348
20.7		Transport of Nutrients349
Water and Mineral Transport in Xylem349
Organic Nutrient Transport in Phloem350
Chapter 21
Plant Responses and Reproduction 355
21.1		Responses in Flowering Plants 356
Plant Hormones356
Environmental Stimuli and Plant Responses360
Photoperiodism360
21.2		Sexual Reproduction in Flowering Plants362
Overview of the Plant Life Cycle362
Flowers362
From Spores to Fertilization364
Development of the Seed in a Eudicot366
Monocots Versus Eudicots366
Fruit Types and Seed Dispersal366
Germination of Seeds368
21.3		Asexual Reproduction in Flowering Plants369
Propagation of Plants in Tissue Culture 369
Genetic Engineering of Plants370

Chapter 22
Being Organized and Steady377
22.1		The Body’s Organization378
Epithelial Tissue Protects380
Connective Tissue Connects and Supports382
Muscular Tissue Moves the Body384
Nervous Tissue Communicates385
22.2		Organs and Organ Systems386
22.3		Homeostasis388
Negative Feedback389
Chapter 23
The Transport Systems395
23.1		Open and Closed Circulatory Systems396
Open Circulatory Systems396
Closed Circulatory Systems397
Comparison of Circulatory Pathways398
23.2		Transport in Humans399
The Human Heart399
Blood Vessels401
Lymphatic System403
Cardiovascular Disorders403
23.3		Blood: A Transport Medium405
Plasma405
Formed Elements405
Capillary Exchange in the Tissues408
Chapter 24
The Maintenance Systems413
24.1		Digestive System414
Tube-Within-a-Tube Body Plan414
Accessory Organs420
Regulation of Digestive Juices421
24.2		Respiratory System422
The Human Respiratory Tract 422
Breathing424
Transport and Internal Exchange of Gases426
24.3		Urinary System and Excretion427
Kidneys427
Problems with Kidney Function430
Chapter 25
Human Nutrition435
25.1		Nutrition436
Introducing the Nutrients437
25.2		The Classes 
of Nutrients438
Carbohydrates438
Lipids 439
Proteins440
Minerals441
Vitamins442
Water442
25.3		Nutrition and Health444
Are You Overweight? 444
Disorders Associated with Obesity446
Eating Disorders448
25.4		How to Plan Nutritious Meals449
The Food Pyramid 449
Dietary Supplements 450
The Bottom Line451
Chapter 26
Defenses Against Disease455
26.1		Organs, Tissues, and Cells of the Immune System456
Lymphatic Organs456
26.2		Nonspecific Defenses458
Barriers to Entry458
The Inflammatory Response458
The Complement System459
Natural Killer Cells459
26.3		Specific Defenses460
B Cells and the Antibody Response460
T Cells and the Cellular Response462
26.4		Immunizations464
26.5		Immune System Problems465
Allergies465
Autoimmune Diseases465
AIDS466
Chapter 27
The Control Systems471
27.1		Nervous System472
The Human Nervous System473
Neurons474
The Nerve Impulse475
The Synapse476
Drug Abuse476
The Central Nervous System478
The Peripheral Nervous System480
27.2		Endocrine System483
The Action of Hormones483
Hypothalamus and Pituitary Gland484
Thyroid and Parathyroid Glands486
Adrenal Glands487
Pancreas487
Chapter 28
Sensory Input and Motor Output493
28.1		The Senses494
Chemical Senses495
Hearing and Balance496
Vision499
Cutaneous Receptors and Proprioceptors501
28.2		The Motor Systems502
The Human Skeleton502
Skeletal Muscle Structure and Physiology505
Chapter 29
Reproduction and Development511
29.1		How Animals Reproduce512
Asexual Versus Sexual Reproduction512
Reproduction in Water Versus on Land513
29.2		Human Reproduction 514
Male Reproductive System514
Female Reproductive System516
Aspects of Reproduction519
29.3		Human Development524
Fertilization524
Early Embryonic Development525
Later Embryonic Development 526
Placenta528
Fetal Development and Birth528

Chapter 30
Ecology of Populations533
30.1		The Human Population 534
Present Population Growth534
Future Population Growth535
More-Developed Versus Less-Developed Countries535
Comparing Age Structures537
Population Growth and Environmental Impact537
30.2		Characteristics of Populations538
Distribution and Density538
Population Growth538
Patterns of Population Growth540
Factors That Regulate Population Growth542
30.3		Life History Patterns and Extinction544
Extinction 545
30.4		 The Scope of Ecology 546
Ecology: A Biological Science547
Chapter 31
Communities and Ecosystems551
31.1		Ecology of Communities 552
Community Composition and Diversity553
Ecological Succession554
Interactions in Communities556
Community Stability558
31.2		Ecology of Ecosystems 560
Autotrophs560
Heterotrophs560
Energy Flow and Chemical Cycling561
Chemical Cycling564
31.3		Ecology of Major Ecosystems568
Primary Productivity570
Chapter 32
Human Impact on the Biosphere575
32.1		Resources and Pollution576
Land577
Water578
Food580
Energy583
Minerals586
Other Sources of Pollution586
32.2		Biodiversity588
Direct Values of Biodiversity588
Indirect Values of Biodiversity590
32.3		Working Toward a Sustainable Society592
Today’s Society592
Characteristics of a Sustainable Society592
Appendix	A 
Periodic Table of the Elements597
Appendix	B 
Metric System603
Glossary605
Credits623
Index627 

Teaching Supplements
	1	A View of Life1

	2	The Chemical Basis of Life15
	3	The Organic Molecules of Life29
	4	Inside the Cell47
	5	The Dynamic Cell69
	6	Energy for Life83
	7	Energy for Cells97

	8	Cellular Reproduction111
	9	Sexual Reproduction127
	10	Patterns of Inheritance141
	11	DNA Biology and Technology159
	12	Gene Regulation and Cancer179
	13	Genetic Counseling195

	14	Darwin and Evolution215
	15	Evolution on a Small Scale231
	16	Evolution on a Large Scale245

	17	The First Forms of Life265
	18	Land Environment: Plants and Fungi283
	19	Both Water and Land: Animals305

	20	Plant Anatomy and Growth337
	21	Plant Responses and Reproduction 355

	22	Being Organized and Steady377
	23	The Transport Systems395
	24	The Maintenance Systems413
	25	Human Nutrition435
	26	Defenses Against Disease455
	27	The Control Systems471
	28	Sensory Input and Motor Output493
	29	Reproduction and Development511

	30	Ecology of Populations533
	31	Communities and Ecosystems551
	32	Human Impact on the Biosphere575

Guided Tour
A brilliant visuals program brings biology to life!
Color Consistency
Color consistency organizes information and clarifies concepts for visual learners. 
Multi-Level Perspective
Illustrations depicting complex structures connect macroscopic and microscopic views to help students connect the two levels.
Combination Art
Drawings of structures are often paired with micrographs to enhance visualization.
Process Figures
These figures break down processes into a series of smaller steps and organize them in an easy-to-follow format. 
Icons
Icons show students how the element being presented relates to the whole structure or process.
Integrated Page Layouts
The innovative page layouts integrate text, art, and photos, enhancing visual appeal and pedagogical value and thereby making it easier for students to understand the material being presented.
The Learning System
Features That Will Facilitate Your Understanding of Biology
Captivating Illustrations 
open the chapter.
A Brief Vignette
relates the illustrations to students’ lives. 
An Outline
lists the major topics for the chapter. 
The Concepts
related to each topic are page referenced.
Check Your Progress 
Questions follow main sections of the text and help students assess their understanding of the material presented.
Chapter Summary
An extensive chapter summary is organized according to the major sections in the chapter. Brief statements, lists, tables, and artwork help students review the important topics and concepts.
End-of-Chapter Study Tools
Thinking Scientifically
Critical thinking questions give students an opportunity to reason as a scientist. Detailed answers to these questions are found in the Answer Appendix in the textbook.
Testing Yourself
Objective and art-based questions allow students to review material and prepare for tests. Answers to these questions are given in the Answer Appendix in the textbook.
Website Reminder
This reminder directs you to the book’s website for additional quiz questions and other study aids.
Bioethical Issue
A bioethical issue is presented at the end of the chapter. These short readings discuss a variety of controversial topics that confront our society. Appropriate questions in the reading help students fully consider the issue and arrive at an opinion.
Understanding the Terms
The boldface terms in the chapter are page referenced, and a matching exercise allows students to test their knowledge of the terms.