100.1 Contents

UNIT 1 What is Life Made of? Chemistry, Cells, Energy

CHAPTER 1

Process of Science 1

Java Report

Making sense of the latest buzz in health-related news

1.1 Conflicting Conclusions 3

1.2 Science Is a Process: Narrowing Down the Possibilities 4

1.3 Anatomy of an Experiment 6

1.4 Sample Size Matters 7

1.5 Everyday Theory vs. Scientific Theory 8

1.6 Side Effects of Caffeine 10

1.7 Correlation Does Not Equal Causation 12

1.8 From the Lab to the Media: Lost in Translation 14

CHAPTER 2

Chemistry and Molecules of Life 20

Mission to Mars

Prospecting for life on the red planet

2.1 Five Functional Traits of Life 25

2.2 Touchdown, Gale Crater 26

2.3 All Matter Is Made of Elements 27

2.4 Carbon Is a Versatile Component of Life’s Molecules 29

UP CLOSE Molecules of Life: Carbohydrates, Proteins, Lipids, Nucleic Acids 30

2.5 A Layer Rich in Phospholipids Defines Cell Boundaries 33

2.6 Water Is Polar and Forms Hydrogen Bonds 34

2.7 Hydrogen Bonds Give Water Its Unique Properties 35

2.8 Water Is a Good Solvent 36

2.9 Solutions Have a Characteristic pH 37

2.10 On the Fringe 38

CHAPTER 3

Cell Structure and Function 44

Wonder Drug

How a chance discovery in a London laboratory revolutionized medicine

3.1 How Penicillin Was Discovered 46

3.2 Cell Theory: All Living Things Are Made of Cells 47

3.3 Prokaryotic and Eukaryotic Cells Have Different Structures 48

3.4 Water Flows across Cell Membranes by Osmosis 49

3.5 Some Antibiotics Inhibit Prokaryotic Ribosomes 52

3.6 Membranes: All Cells Have Them 53

3.7 Molecules Move across the Cell Membrane 55

3.8 Eukaryotic Cells Have Organelles 56

UP CLOSE Eukaryotic Organelles 58

M1 MILESTONES IN BIOLOGY

Scientific Rebel 66

Lynn Margulis and the theory of endosymbiosis

M1.1 Chloroplasts and Mitochondria Share Traits with Bacteria 69

M1.2 The First Eukaryotes Were Products of Endosymbiosis 70

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CHAPTER 4

Nutrition, Metabolism, enzymes 74

The Peanut Butter Project

A doctor’s crusade to end malnutrition in Africa, a spoonful at a time

4.1 Hunger around the World 77

4.2 Food Is a Source of Macronutrients 78

4.3 Macronutrients Build and Maintain Cells 79

4.4 Enzymes Facilitate Chemical Reactions 82

4.5 Enzymes Catalyze Reactions by Lowering Activation Energy 83

TABLE 4.1 A Sample of Micronutrients in Your Diet 85

4.6 Vitamins and Minerals Have Essential Functions 86

4.7 Peanut Butter-Based RUTF Saves More Children 88

4.8 A Balanced Diet 90

CHAPTER 5

Energy and Photosynthesis 94

The Future of Fuel

Scientists hope to make algae into the next global energy source

5.1 Distribution of Recoverable Oil Reserves 96

5.2 U.S. Energy Consumption 98

5.3 Algae Capture Energy in Their Molecules 99

5.4 Energy Is Conserved 100

5.5 Energy Conversion Is Not Efficient 101

5.6 Autotrophs Convert Light Energy into Chemical Energy 102

5.7 Photosynthesis Captures Sunlight to Make Food 103

5.8 The Energy in Sunlight Travels in Waves 106

5.9 Photosynthesis: A Closer Look 107

TABLE 5.1 How Green Are Biofuels? 108

Americans burn through 378 million gallons of gasoline a day, enough to fill about 540 Olympic-size swimming pools.

— CHAPTER 5

CHAPTER 6

Dietary Energy and Cellular Respiration 114

Supersize Me?

The biology and culture of our expanding waistlines

6.1 Obesity Is Influenced by Biology and Culture 116

6.2 Body Mass Index (BMI) 117

6.3 Americans Eat Large Portions 118

6.4 Food Powers Cellular Work 120

TABLE 6.1 Calories In, Calories Out 121

6.5 Glycogen and Fat Store Excess Calories 122

6.6 ATP: The Energy Currency of Cells 124

6.7 Aerobic Respiration Transfers Food Energy to ATP 125

6.8 Aerobic Respiration: A Closer Look 126

6.9 Fermentation Occurs When Oxygen Is Scarce 127

6.10 Photosynthesis and Aerobic Respiration Form a Cycle 129

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UNIT 2 How Does Life Perpetuate? Cell Division and Inheritance

CHAPTER 7

DNA Structure and Replication 136

Biologically Unique

How DNA helped free an innocent man

7.1 What Is DNA, and Where Is It Found? 139

7.2 DNA Is Made of Two Strands of Nucleotides 140

7.3 DNA Structure Provides a Mechanism for DNA Replication 142

7.4 The Polymerase Chain Reaction Amplifies Small Amounts of DNA 144

7.5 DNA Profiling Uses Short Tandem Repeats 146

7.6 Creating a DNA Profile 147

7.7 DNA Profiling Uses Many Different STRs 148

M2 MILESTONES IN BIOLOGY

The Model Makers 154

Watson, Crick, and the structure of DNA

M2.1 The DNA Puzzle 156

M2.2 Rosalind Franklin and the Shape of DNA 157

M2.3 Erwin Chargaff’s Work Provided a Clue to Base Pairing 158

M2.4 The Structure Is Finally Known: The DNA Double Helix 159

CHAPTER 8

Genes to Proteins 162

Medicine from Milk

Scientists genetically modify animals to make medicine

8.1 Amino Acid Sequence Determines Protein Shape and Function 165

8.2 Chromosomes Include Gene Sequences That Code for Proteins 166

8.3 Antithrombin Deficiency Can Cause Blood Clots 167

8.4 Genes to Proteins: Different Alleles Influence Protein Function 168

8.5 The Two Parts of a Gene 169

8.6 Making a Transgenic Goat 171

8.7 Gene Expression: An Overview 173

8.8 Transcription: A Closer Look 174

8.9 Translation: A Closer Look 175

8.10 The Genetic Code Is Universal 176

M3 MILESTONES IN BIOLOGY

Sequence Sprint 182

Venter and Collins race to decode the human genome

M3.1 DNA Sequencing: Hierarchical Shotgun Method 184

M3.2 DNA Sequencing: Whole-Genome Shotgun Method 186

M3.3 New Technology Cut DNA Sequencing Time and Cost 187

M3.4 Linking Genes to Disease 190

CHAPTER 9

Cell Division and Mitosis 192

Nature’s Pharmacy

From the bark of an ancient evergreen tree, a cancer treatment blockbuster

9.1 Why Do Cells Divide? 195

9.2 The Cell Cycle: How Cells Reproduce 196

TABLE 9.1 Drugs from Plants 198

UP CLOSE Cell Cycle and Mitosis 200

9.3 Taxol Interferes with Mitosis 202

9.4 Cell Division Is Tightly Regulated 203

9.5 Cancer: When Checkpoints Fail 204

9.6 Taxol Prolongs Survival in Cancer Patients 207

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CHAPTER 10

Mutations and Cancer 212

Fighting Fate

When cancer runs in the family, ordinary measures are not enough

10.1 Mutations in the BRCA1 Gene Increase the Risk of Cancer 215

10.2 Replication Errors and Other DNA Damage Can Produce New Alleles 216

10.3 Mutations Can Be Hereditary or Nonhereditary 217

TABLE 10.1 Incidence of Hereditary Diseases in Different Populations 218

10.4 Mutations in DNA Can Alter Protein Function and Cause Cancer 219

10.5 What Causes Mutations? 220

10.6 Mutations in Two Types of Cell Cycle Genes Cause Most Types of Cancer 221

10.7 Tumors Develop in Stages as Mutations Accumulate in a Cell 222

10.8 BRCA Mutations Increase the Risk of Breast and Ovarian Cancer 223

TABLE 10.2 Reducing the Risk of Cancer 224

CHAPTER 11

Single-Gene Inheritance and Meiosis 228

Rock for a Cause

From patient to performer, shining the spotlight on a genetic disease

11.1 CF Is Caused by Mutations in the CFTR Gene 230

11.2 Humans Have Two Copies of Nearly Every Gene 232

11.3 Gametes Pass Genetic Information to the Next Generation 233

11.4 Meiosis Produces Haploid Egg and Sperm 234

11.5 Meiosis Produces Genetically Diverse Egg and Sperm 235

11.6 The CFTR Protein and Cystic Fibrosis 236

11.7 How Recessive Traits Are Inherited 238

11.8 How Dominant Traits Are Inherited 239

TABLE 11.1 Inherited Genetic Conditions in Humans 240

11.9 Tracking the Inheritance of Two Genes 241

Mendel provided a new explanation for heredity, decades before the word “genetics” was coined.

— MILESTONE 4

M4 MILESTONES IN BIOLOGY

Mendel’s Garden 248

An Austrian monk lays the foundation for modern genetics

M4.1 Theories of Inheritance before Mendel 250

M4.2 Mendel’s Experiments 252

M4.3 Mendel’s Law of Segregation 253

M4.4 Mendel’s Law of Independent Assortment 254

CHAPTER 12

Complex Inheritance 256

Q&A: Genetics

Complexities of human genetics, from sex to depression

12.1 X and Y Chromosomes Determine Human Sex 258

TABLE 12.1 Between Male and Female: Varieties of Sex and Intersex 260

12.2 X-Linked Traits Are Inherited on X Chromosomes 261

12.3 Female Carriers Can Pass Disease Alleles to Their Children 262

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12.4 Y Chromosomes Pass Largely Unchanged from Fathers to Sons 264

12.5 DNA Links Sally Hemings’s Son to Jefferson 265

12.6 Hair Texture Exhibits Incomplete Dominance 268

12.7 Human Blood Type Is a Codominant Trait 269

12.8 A Mismatched Blood Transfusion Causes Immune Rejection 270

12.9 Human Height Is Both Polygenic and Multifactorial 272

12.10 Serotonin Transporter Function Is Linked to Depression 273

12.11 Depression Is a Multifactorial Trait 274

12.12 Chromosomal Abnormalities: Aneuploidy 276

12.13 Amniocentesis Provides a Fetal Karyotype 277

CHAPTER 13

Stem Cells and Cell Differentiation 282

Grow Your Own

Stem cells could be the key to engineering organs

13.1 Stem Cells in Tissues Have Regenerative Properties 285

13.2 Cells Are Organized into Tissues, Organs, and Systems 286

13.3 Engineering an Organ Using Stem Cells 286

TABLE 13.1 How Old Are You? 288

13.4 Specialized Cells Express Different Genes 289

13.5 Regenerative Medicine: Four Approaches 290

13.6 Embryonic vs. Adult Stem Cells 292

13.7 Somatic Cell Nuclear Transfer Produces Cloned Embryonic Stem Cells 294

13.8 Induced Stem Cells 295

UNIT 3 How Does Life Change over Time? Evolution and Diversity

CHAPTER 14

Natural Selection and Adaptation 302

Bugs That Resist Drugs

Drug-resistant bacteria are on the rise. Can we stop them?

14.1 The Bacterium Staphylococcus aureus 305

14.2 How Beta-Lactam Antibiotics Work 307

14.3 How Bacteria Reproduce 308

14.4 How Bacterial Populations Acquire Genetic Variation 309

14.5 An Organism’s Fitness Depends on Its Environment 310

14.6 Evolution by Natural Selection 311

14.7 Patterns of Natural Selection 312

14.8 Preventing and Treating Infection by Antibiotic-Resistant Bacteria 315

M5 MILESTONES IN BIOLOGY

Adventures in Evolution 320

Charles Darwin and Alfred Russel Wallace on the trail of natural selection

M5.1 Lamarckianism: An Early Idea about Evolution 323

M5.2 Darwin’s Voyage on the Beagle 324

M5.3 The Evolution of Darwin’s Thought 326

M5.4 The Evolution of Wallace’s Thought 328

Scientists are now seeing bacterial infections that don’t respond to any known antibiotics, leading many to fear the day when we run out of treatment options altogether.

— CHAPTER 14

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CHAPTER 15

Nonadaptive Evolution and Speciation 330

Urban Evolution

How cities are altering the fate of species

15.1 Population Genetics 333

15.2 Gene Pools of New York City Mouse Populations 335

15.3 Genetic Drift Reduces Genetic Diversity 336

15.4 Gene Flow Increases Genetic Diversity in Populations 338

15.5 City Mouse and Country Mouse 340

TABLE 15.1 Adaptive and Nonadaptive Mechanisms of Evolution 341

UP CLOSE Calculating the Hardy-Weinberg Equilibrium 342

15.6 Species Are Reproductively Isolated 346

15.7 Speciation: How One Species Can Become Many 347

CHAPTER 16

Evidence for Evolution 352

A Fish with Fingers?

A transitional fossil fills a gap in our knowledge of evolution

16.1 Fossils Form Only in Certain Circumstances 356

16.2 Fossils Reveal Changes in Species over Time 357

16.3 How Fossils Are Dated 359

16.4 Tiktaalik, an Intermediate Fossilized Organism 363

16.5 Forelimb Homology in Fish and Tetrapods 364

16.6 Vertebrate Animals Share a Similar Pattern of Early Development 365

16.7 Related Organisms Share DNA Sequences 367

CHAPTER 17

Life on Earth 372

Q&A: Evolution

From moon rocks to DNA, clues to the history of life on Earth

17.1 Unstable Elements Undergo Radioactive Decay 375

17.2 Radioactive Decay Is Used to Date Some Rock Types 376

17.3 Geologic Timeline of Life on Earth 378

17.4 Movement of Earth’s Plates Influences Climate and Biogeography 380

17.5 How Many Species Are There? 382

17.6 Classification of Species 383

17.7 How to Read a Phylogenetic Tree 384

17.8 Genetics Defines Three Domains of Life: Bacteria, Archaea, Eukarya 386

CHAPTER 18

Prokaryotic Diversity 390

Lost City

Probing life’s origins at the bottom of the sea

18.1 Hydrothermal Vents of Lost City Provide an Extreme Environment for Life 392

18.2 Investigating Life in Lost City 394

18.3 Prokaryotic Cells Are Small and Lack Organelles 396

18.4 Prokaryotes Are Abundant and Diverse 397

18.5 Bacteria and Archaea, Life’s Prokaryotic Domains 398

18.6 Exploring Bacterial Diversity 400

18.7 Exploring Archaeal Diversity 402

18.8 Energy from the Earth Fuels Life at Lost City 404

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“[Lost City] is a good example of what we really don’t know and what there is to still discover on the seafloor.”

— GRETCHEN FRÜH-GREEN, CHAPTER 18

CHAPTER 19

Eukaryotic Diversity 410

Rain Forest Riches

Restoring eukaryotic diversity in Olympic National Park

19.1 Tree of Life: Domain Eukarya 412

19.2 The Landscape of Olympic National Park 413

19.3 Evolution of Plant Diversity 414

19.4 Evolution of Animal Diversity 417

19.5 Fungi, the Decomposers 422

19.6 The Challenge of Classifying Protists 423

CHAPTER 20

Human Evolution 430

Skin Deep

Science redefines the meaning of racial categories

20.1 Humans Are Genetically Similar 432

20.2 Melanin Influences Skin Color 433

20.3 Folate and Vitamin D Are Necessary for Reproductive Health 435

20.4 Human Skin Color Correlates with UV Light Intensity 436

20.5 Mitochondrial DNA Is Inherited from Mothers 437

20.6 Modern Human Populations Share a Common Female Ancestor 438

20.7 Out of Africa: Human Migration 439

20.8 Traits of Modern Humans Reflect Evolutionary History 440

20.9 Natural Selection Influences Human Evolution 442

20.10 The Evolution of Skin Color 444

UNIT 4 What Makes Up Our Environment? Ecology

CHAPTER 21

Population Ecology 448

On the Tracks of Wolves and Moose

Ecologists learn big lessons from a small island

21.1 Ecology of Isle Royale 451

21.2 Distribution Patterns Influence Population Sampling Methods 452

21.3 Population Distribution Patterns 453

21.4 Population Growth and Carrying Capacity 455

21.5 Population Cycles of Predator and Prey 456

21.6 Patterns of Population Growth 457

21.7 Moose and Wolf Health Is Monitored by a Variety of Data 458

21.8 Abiotic and Biotic Influences on Population Growth 459

21.9 A Warming Climate Influences Moose and Wolf Population Size 462

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CHAPTER 22

Community Ecology 466

What’s Happening to Honey Bees?

A mysterious ailment threatens a vital link in the food chain

22.1 Bees Are Keystone Species 468

22.2 Commercial Crops Require Bees 469

22.3 Flowering Plant Reproduction Relies on Pollinators 470

22.4 Energy Flows up a Food Chain 472

22.5 A Honey Bee Food Web 473

22.6 Organisms May Live Together in Symbioses 474

22.7 Pollinators Have Different Ecological Niches 476

22.8 Bees Compete for Resources 477

22.9 What Is Causing Colony Collapse Disorder? 480

CHAPTER 23

Ecosystem Ecology 486

The Heat Is On

From migrating maples to shrinking sea ice, signs of a warming planet

23.1 U.S. Maple Syrup: A Thing of the Past? 488

23.2 Rising Temperatures Affect Plant Behavior 489

23.3 Maple Tree Range Is Affected by Rising Temperatures 491

UP CLOSE Biomes 492

23.4 The Greenhouse Effect 493

23.5 Earth’s Surface Temperature Is Rising with Increases in Greenhouse Gases like Carbon Dioxide 494

23.6 Rising Temperatures Mean Widespread Ecosystem Change 495

23.7 Arctic Temperatures Are Rising Fast 497

23.8 Arctic Sea Ice Is Melting 498

23.9 The Carbon Cycle 499

UP CLOSE Chemical Cycles 500

23.10 Measuring Atmospheric Carbon Dioxide Levels 502

23.11 Anthropogenic Production of Greenhouse Gases 503

M6 MILESTONES IN BIOLOGY

Progress or Poison? 510

Rachel Carson, pesticides, and the birth of the environmental movement

M6.1 Widespread Use of DDT to Kill Mosquitoes and Lice 513

M6.2 Unintended Consequences of Using DDT 514

M6.3 Biomagnification 515

CHAPTER 24

Sustainability 520

The Makings of a Green City

One Kansas town reinvents itself sustainable

24.1 The Human Ecological Footprint 524

24.2 The Human Ecological Footprint Is Greater than Earth’s Biocapacity 526

24.3 Countries Differ in Their Ecological Footprint 527

24.4 Fossil Fuels Are Nonrenewable 528

24.5 Human Population Growth 532

24.6 Species Loss Increases as Human Population Grows 534

24.7 Nonfossil Fuel Resources Reduce Our Ecological Footprint 536

24.8 Water Is a Renewable Resource 537

24.9 Depletion of Freshwater by a Growing Population 539

24.10 Water Availability Is Not Equally Distributed 540

24.11 What You Can Do to Live More Sustainably 541

xxv

UNIT 5 How Do Organisms Work? Physiology

CHAPTER 25

Overview of Physiology 546

Man vs. Mountain

Physiology explains a 1996 disaster on Everest

25.1 How the Human Body Is Organized 549

25.2 The Body Works to Maintain Homeostasis 551

25.3 Thermoregulation in Response to Cold and Heat 552

25.4 Homeostasis Feedback Loops Require Sensors and Effectors 555

UP CLOSE Organ Systems 556

25.5 The Pancreas Regulates Blood Glucose Levels 559

25.6 The Kidneys Respond to Changes in Water Balance 561

25.7 Insulation Helps Keep Some Endotherms Warm 562

25.8 Some Organisms Generate Heat from Nonshivering Thermogenesis 564

CHAPTER 26

Digestive System 568

Drastic Measures

For the morbidly obese, stomach-shrinking surgery is a last resort

26.1 The Digestive System 571

26.2 The Upper Digestive Tract 572

26.3 Gastric Bypass Surgery 573

26.4 Most Chemical Digestion Occurs in the Small Intestine 575

26.5 The Small Intestine Absorbs Nutrients 576

26.6 Gastric Banding Surgery 577

26.7 The Large Intestine 578

26.8 Weight-loss Surgery Saves Lives 579

M7 MILESTONES IN BIOLOGY

Stumbling on a Cure 586

Banting, Best, and the discovery of insulin

M7.1 The Pancreas Produces Digestive Enzymes and Insulin 588

M7.2 Banting and Best Isolated Insulin From Dog Pancreases 590

M7.3 Insulin and Diabetes 593

CHAPTER 27

Cardiovascular System 596

Death in Bogalusa

From tragic deaths in a southern town, insight into heart disease

27.1 Cardiovascular Disease Is the Major Killer in the U.S. 599

27.2 The Cardiovascular System 600

27.3 Blood Flow Follows a Double Circuit 602

27.4 Atherosclerosis: A Common Cause of Cardiovascular Disease 603

27.5 Capillaries Are Sites of Nutrient and Gas Exchange 604

27.6 The Components of Blood 605

27.7 High Blood Pressure Can Result in Atherosclerosis 606

27.8 Risk Factors and Heart Disease 608

27.9 Cholesterol: Good and Bad 609

27.10 Obesity in the United States Is on the Rise 610

27.11 Southern States Have the Highest Average Incidence of Cardiovascular Disease 611

The human heart beats more than 2.5 billion times in an average lifetime.

— CHAPTER 27

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CHAPTER 28

Respiratory System 620

Peak Performance

An inside look at altitude training among elite athletes

28.1 The Human Respiratory System 624

28.2 Gas Exchange and Transport 625

28.3 Effect of Altitude on the Blood 626

28.4 The Relationship between Altitude and Oxygen Pressure 628

28.5 Altitude Training Hypothesis 629

28.6 Ventilation: How We Take a Breath 630

28.7 Altitude Training Improves Performance 632

28.8 Hemoglobin Carries Oxygen in Red Blood Cells 633

28.9 EPO and Blood Doping 634

CHAPTER 29

Central Nervous System 642

Smoke on the Brain

Neuroscience explains why nicotine and other drugs are hard to kick

29.1 Nicotine Stimulates Pleasure in the Brain 645

29.2 The Central and Peripheral Nervous Systems Work Together 646

29.3 Neurons Are Highly Specialized 647

29.4 Electrical Signals Are Transmitted Along Axons 648

29.5 Functional Regions of the Brain 650

29.6 Neurons Use Chemical Signals to Communicate 651

29.7 Addictive Drugs Alter Dopamine Signaling 653

TABLE 29.1 Potentially Addictive Drugs and Their Effects 654

29.8 Drugs Diminish Memory and Motor Skills 656

CHAPTER 30

Reproductive System 664

Too Many Multiples?

The birth of octuplets raises questions about the fertility business

30.1 Female Reproductive System 667

30.2 Male Reproductive System 668

30.3 Fertilization Occurs in the Female Oviduct 669

30.4 In Vitro Fertilization (IVF) 670

30.5 Hormones Regulate the Menstrual Cycle 672

30.6 Hormones Support Pregnancy 673

TABLE 30.1 Contraception 674

30.7 Sperm Develop in The Testes 675

30.8 Causes of Infertility 676

30.9 Assisted Reproductive Technologies Can Result in Multiple Births 678

UP CLOSE Prenatal Development 680

CHAPTER 31

Immune System 690

The Forgotten Plague

After nearly a century, scientists learn what made the 1918 influenza pandemic so deadly

31.1 Viruses Infect and Replicate in Host Cells 693

31.2 The Immune System Defends against a Variety of Pathogens 695

31.3 Innate and Adaptive Immunity 696

31.4 Some Important Features of Innate Immunity 698

31.5 Lung Inflammation Can Kill 700

31.6 The Lymphatic System: Where B and T Lymphocytes Develop 702

31.7 Humoral Immunity: B Cells and Antibody Production 703

31.8 Cell-Mediated Immunity: Cytotoxic T Cells Kill Infected Cells 704

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31.9 Memory Cells Mount an Aggressive Secondary Response 706

31.10 Antigenic Drift and Shift Create New Influenza Strains 707

TABLE 31.1 Known Flu Pandemics 709

Plants are among the most “flirtatious” and sexually active organisms on Earth.

— CHAPTER 32

CHAPTER 32

Plant Physiology 716

Q&A: Plants

Exploding seeds, carnivorous flowers, and other colorful adaptations of the plant world

32.1 All Plants Share the Same Basic Design 718

32.2 Plants Transport Water and Sugar Through Their Vascular System 720

32.3 Plants Obtain Nutrients in a Variety of Ways 722

32.4 Beating the Heat: Doing Photosynthesis without Drying Out 724

32.5 Plants Produce Multiple Light-Capturing Pigments 726

32.6 Plants Reproduce Sexually 727

32.7 Seeds Carry a Young Plant to a New Destination 728

32.8 Plants Sense and Respond to Their Environment 730

32.9 Ethylene Promotes Fruit Ripening 731

32.10 Hormones Trigger Plant Growth and Development 732

32.11 Plants Defend Themselves 733

Answers 738

Glossary 749

Photo Credits 762

Index 768