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Copyright, iv
Preface, xxi
About the Authors, xxvii
1. An Introduction to Life on Earth, xxx
Case Study: Life on Earth—and Elsewhere?, 1
1.1. How Do Scientists Study Life?, 2
Life Can Be Studied at Different Levels of Organization, 2
Scientific Principles Underlie All Scientific Inquiry, 3
The Scientific Method Is the Basis for Scientific Inquiry, 4
Communication Is Crucial to Science, 5
Science Is a Human Endeavor, 5
Scientific Inquiry: Controlled Experiments, Then and Now, 6
Scientific Theories Have Been Thoroughly Tested, 8
1.2. Evolution: The Unifying Theory of Biology, 9
Three Natural Processes Underlie Evolution, 9
1.3. What Are the Characteristics of Living Things?, 10
Living Things Are Complex, Organized, and Composed of Cells, 11
Living Things Maintain Relatively Constant Internal Conditions Through Homeostasis, 11
Earth Watch: Why Preserve Biodiversity?, 12
Living Things Respond to Stimuli, 13
Living Things Acquire and Use Materials and Energy, 13
Links to Life: The Life Around Us, 14
Living Things Grow, 14
Living Things Reproduce Themselves, 14
Living Things, Collectively, Have the Capacity to Evolve, 14
1.4. How Do Scientists Categorize the Diversity of Life?, 14
The Domains Bacteria and Archaea Consist of Prokaryotic Cells; the Domain Eukarya Is Composed of Eukaryotic Cells, 14
Bacteria, Archaea, and Protists Are Mostly Unicellular; Members of the Kingdoms Fungi, Plantae, and Animalia Are Primarily Multicellular, 15
Members of the Different Kingdoms Have Different Ways of Acquiring Energy, 15
1.5. How Does Knowledge of Biology Illuminate Everyday Life?, 15
Case Study Revisited: Life on Earth—and Elsewhere?, 17
Chapter Review, 17
Unit 1. The Life of a Cell, 19
2. Atoms, Molecules, and Life, 20
Case Study: Walking on Water, 21
2.1. What Are Atoms?, 22
Atoms, the Basic Structural Units of Matter, Are Composed of Still Smaller Particles, 22
2.2. How Do Atoms Interact to Form Molecules?, 23
Atoms Interact with Other Atoms When There Are Vacancies in Their Outermost Electron Shells, 23
Scientific Inquiry: Radioactivity in Research, 24
Charged Atoms Called Ions Interact to Form Ionic Bonds, 25
Uncharged Atoms Can Become Stable by Sharing Electrons, Forming Covalent Bonds, 26
Hydrogen Bonds Are Electrical Attractions Between or Within Molecules with Polar Covalent Bonds, 28
2.3. Why Is Water So Important to Life?, 28
Water Interacts with Many Other Molecules, 28
Links to Life: Health Food?, 29
Water Molecules Tend to Stick Together, 30
Water-Based Solutions Can Be Acidic, Basic, or Neutral, 31
Water Moderates the Effects of Temperature Changes, 32
Water Forms an Unusual Solid: Ice, 32
Case Study Revisited: Walking on Water, 33
Chapter Review, 34
3. Biological Molecules, 36
Case Study: Puzzling Proteins, 37
3.1. Why Is Carbon So Important in Biological Molecules?, 38
3.2. How Are Organic Molecules Synthesized?, 38
Biological Molecules Are Joined Together or Broken Apart by Removing or Adding Water, 39
3.3. What Are Carbohydrates?, 39
There Are Several Monosaccharides with Slightly Different Structures, 39
Links to Life: Fake Food?, 41
Disaccharides Consist of Two Single Sugars Linked by Dehydration Synthesis, 41
Polysaccharides Are Chains of Single Sugars, 42
3.4. What Are Lipids?, 44
Oils, Fats, and Waxes Are Lipids Containing Only Carbon, Hydrogen, and Oxygen, 44
Phospholipids Have Water-Soluble “Heads” and Water-Insoluble “Tails”, 46
Steroids Consist of Four Carbon Rings Fused Together, 46
Health Watch: Cholesterol—Friend and Foe, 47
3.5. What Are Proteins?, 47
Proteins Are Formed from Chains of Amino Acids, 48
Amino Acids Are Joined to Form Chains by Dehydration Synthesis, 49
A Protein Can Have Up to Four Levels of Structure, 49
The Functions of Proteins Are Linked to Their Three-Dimensional Structures, 51
A Closer Look: A Hairy Subject, 52
3.6. What Are Nucleic Acids?, 53
DNA and RNA, the Molecules of Heredity, Are Nucleic Acids, 53
Other Nucleotides Act as Intracellular Messengers and Energy Carriers, 53
Case Study Revisited: Puzzling Proteins, 54
Chapter Review, 54
4. Cell Structure and Function, 56
Case Study: Spare Parts for Human Bodies, 57
4.1. What Is the Cell Theory?, 59
4.2. What Are the Basic Attributes of Cells?, 59
Cell Function Limits Cell Size, 59
All Cells Share Common Features, 59
There Are Two Basic Types of Cells: Prokaryotic and Eukaryotic, 62
4.3. What Are the Major Features of Eukaryotic Cells?, 63
Some Eukaryotic Cells Are Supported by Cell Walls, 63
The Cytoskeleton Provides Shape, Support, and Movement, 63
Scientific Inquiry: The Search for the Cell, 64
Cilia and Flagella Move the Cell Through Fluid or Move Fluid Past the Cell, 67
The Nucleus Is the Control Center of the Eukaryotic Cell, 67
Eukaryotic Cytoplasm Includes an Elaborate System of Membranes, 70
Vacuoles Serve Many Functions, Including Water Regulation, Support, and Storage, 72
Mitochondria Extract Energy from Food Molecules, and Chloroplasts Capture Solar Energy, 73
Plants Use Plastids for Storage, 74
4.4. What Are the Major Features of Prokaryotic Cells?, 75
Prokaryotic Cells Are Small and Possess Specialized Surface Features, 75
Prokaryotic Cells Have Fewer Specialized Structures Within Their Cytoplasm, 76
Links to Life: Unwanted Guests, 77
Case Study Revisited: Spare Parts for Human Bodies, 77
Chapter Review, 78
5. Cell Membrane Structure and Function, 80
Case Study: Vicious Venoms, 81
5.1. How Is the Structure of a Membrane Related to Its Function?, 82
Cell Membranes Isolate the Cell Contents While Allowing Communication with the Environment, 82
Membranes Are “Fluid Mosaics” in Which Proteins Move Within Layers of Lipids, 82
The Phospholipid Bilayer Is the Fluid Portion of the Membrane, 83
A Variety of Proteins Form a Mosaic Within the Membrane, 84
5.2. How Do Substances Move Across Membranes?, 85
Molecules in Fluids Move in Response to Gradients, 85
Movement Across Membranes Occurs by Both Passive and Active Transport, 86
Passive Transport Includes Simple Diffusion, Facilitated Diffusion, and Osmosis, 86
Scientific Inquiry: The Discovery of Aquaporins, 89
Active Transport Uses Energy to Move Molecules Against Their Concentration Gradients, 92
Cells Engulf Particles or Fluids by Endocytosis, 92
Exocytosis Moves Material Out of the Cell, 94
Exchange of Materials Across Membranes Influences Cell Size and Shape, 94
5.3. How Do Specialized Junctions Allow Cells to Connect and Communicate?, 95
Desmosomes Attach Cells Together, 95
Tight Junctions Make Cell Attachments Leakproof, 95
Gap Junctions and Plasmodesmata Allow Direct Communication Between Cells, 96
Evolutionary Connections: Caribou Legs and Membrane Diversity, 96
Case Study Revisited: Vicious Venoms, 97
Chapter Review, 98
6. Energy Flow in the Life of a Cell, 100
Case Study: Energy Unleashed, 101
6.1. What Is Energy?, 102
The Laws of Thermodynamics Describe the Basic Properties of Energy, 102
Living Things Use the Energy of Sunlight to Create the Low-Entropy Conditions of Life, 103
6.2. How Does Energy Flow in Chemical Reactions?, 103
Exergonic Reactions Release Energy, 104
Endergonic Reactions Require a Net Input of Energy, 105
Coupled Reactions Link Exergonic with Endergonic Reactions, 105
6.3. How Is Cellular Energy Carried Between Coupled Reactions?, 105
ATP Is the Principal Energy Carrier in Cells, 105
Electron Carriers Also Transport Energy Within Cells, 107
6.4. How Do Cells Control Their Metabolic Reactions?, 108
At Body Temperatures, Spontaneous Reactions Proceed Too Slowly to Sustain Life, 108
Catalysts Reduce Activation Energy, 108
Enzymes Are Biological Catalysts, 108
Cells Regulate Metabolism by Controlling Enzymes, 110
Poisons, Drugs, and Environmental Conditions Influence Enzyme Activity, 111
Links to Life: Lack of an Enzyme Leads to Lactose Intolerance, 113
Case Study Revisited: Energy Unleashed, 113
Chapter Review, 113
7. Capturing Solar Energy: Photosynthesis, 116
Case Study: Did the Dinosaurs Die from Lack of Sunlight?, 117
7.1. What Is Photosynthesis?, 118
Leaves and Chloroplasts Are Adaptations for Photosynthesis, 118
Photosynthesis Consists of Light-Dependent and Light-Independent Reactions, 119
7.2. Light-Dependent Reactions: How Is Light Energy Converted to Chemical Energy?, 120
During Photosynthesis, Light Is First Captured by Pigments in Chloroplasts, 120
The Light-Dependent Reactions Occur in Association with the Thylakoid Membranes, 121
A Closer Look: Chemiosmosis—ATP Synthesis in Chloroplasts, 124
7.3. Light-Independent Reactions: How Is Chemical Energy Stored in Glucose Molecules?, 125
The C₃ Cycle Captures Carbon Dioxide, 125
Carbon Fixed During the C₃ Cycle Is Used to Synthesize Glucose, 126
7.4. What Is the Relationship Between Light-Dependent and Light-Independent Reactions?, 127
7.5. Water, CO₂, and the C₄ Pathway, 127
When Stomata Are Closed to Conserve Water, Wasteful Photorespiration Occurs, 127
C₄ Plants Reduce Photorespiration by Means of a Two-Stage Carbon-Fixation Process, 129
C₃ and C₄ Plants Are Each Adapted to Different Environmental Conditions, 129
Links to Life: You Owe Your Life to Plants, 129
Case Study Revisited: Did the Dinosaurs Die from Lack of Sunlight?, 130
Chapter Review, 130
8. Harvesting Energy: Glycolysis and Cellular Respiration, 132
Case Study: When Athletes Boost Their Blood Counts: Do Cheaters Prosper?, 133
8.1. How Do Cells Obtain Energy?, 134
Photosynthesis Is the Ultimate Source of Cellular Energy, 134
Glucose Is a Key Energy-Storage Molecule, 134
An Overview of Glucose Breakdown, 134
8.2. How Is the Energy in Glucose Captured During Glycolysis?, 135
Glycolysis Breaks Down Glucose to Pyruvate, Releasing Chemical Energy, 135
In the Absence of Oxygen, Fermentation Follows Glycolysis, 135
A Closer Look: Glycolysis, 136
8.3. How Does Cellular Respiration Capture Additional Energy from Glucose?, 138
Cellular Respiration in Eukaryotic Cells Occurs in Mitochondria, 138
Links to Life: A Jug of Wine, a Loaf of Bread, and a Nice Bowl of Sauerkraut, 139
Pyruvate Is Broken Down in the Mitochondrial Matrix, Releasing More Energy, 139
High-Energy Electrons Travel Through the Electron Transport Chain, 140
A Closer Look: The Mitochondrial Matrix Reactions, 141
Chemiosmosis Captures Energy Stored in a Hydrogen Ion Gradient and Produces ATP, 141
8.4. Putting It All Together, 142
A Summary of Glucose Breakdown in Eukaryotic Cells, 142
Glycolysis and Cellular Respiration Influence the Way Organisms Function, 143
Health Watch: Why Can You Get Fat by Eating Sugar?, 144
Case Study Revisited: When Athletes Boost Their Blood Counts: Do Cheaters Prosper?, 145
Chapter Review, 145
Unit 2. Inheritance, 147
9. DNA: The Molecule of Heredity, 148
Case Study: Muscles, Mutations, and Myostatin, 149
9.1. How Did Scientists Discover That Genes Are Made of DNA?, 150
Transformed Bacteria Revealed the Link Between Genes and DNA, 150
9.2. What Is the Structure of DNA?, 151
Scientific Inquiry: DNA Is the Hereditary Molecule of Bacteriophages, 152
DNA Is Composed of Four Nucleotides, 154
DNA Is a Double Helix of Two Nucleotide Strands, 154
Hydrogen Bonds Between Complementary Bases Hold the Two DNA Strands Together, 154
Scientific Inquiry: The Discovery of the Double Helix, 156
9.3. How Does DNA Encode Information?, 157
9.4. How Does DNA Replication Ensure Genetic Constancy During Cell Division?, 157
Replication of DNA Is a Critical Event in a Cell’s Life, 157
DNA Replication Produces Two DNA Double Helices, Each with One Original Strand and One New Strand, 157
9.5. How Do Mutations Occur?, 158
A Closer Look: DNA Structure and Replication, 159
Accurate Replication and Proofreading Produce Almost Error-Free DNA, 163
Mistakes Do Happen, 163
Mutations Range from Changes in Single Nucleotide Pairs to Movements of Large Pieces of Chromosomes, 163
Mutations May Have Varying Effects on Function, 163
Case Study Revisited: Muscles, Mutations, and Myostatin, 163
Chapter Review, 164
10. Gene Expression and Regulation, 166
Case Study: Vive la Différence!, 167
10.1. How Are Genes and Proteins Related?, 168
Most Genes Contain the Information for the Synthesis of a Single Protein, 168
DNA Provides Instructions for Protein Synthesis via RNA Intermediaries, 169
Overview: Genetic Information Is Transcribed into RNA and Then Translated into Protein, 170
The Genetic Code Uses Three Bases to Specify an Amino Acid, 171
10.2. How Is Information in a Gene Transcribed into RNA?, 172
Initiation of Transcription Occurs When RNA Polymerase Binds to the Promoter of a Gene, 172
Elongation Proceeds Until RNA Polymerase Reaches a Termination Signal, 172
10.3. How Is the Base Sequence of a Messenger RNA Molecule Translated into Protein?, 174
Messenger RNA Carries the Code for Protein Synthesis from DNA to Ribosomes, 174
Ribosomes Consist of Two Subunits, Each Composed of Ribosomal RNA and Protein, 176
Transfer RNA Molecules Decode the Sequence of Bases in mRNA into the Amino Acid Sequence of a Protein, 176
During Translation, mRNA, tRNA, and Ribosomes Cooperate to Synthesize Proteins, 176
Links to Life: Genetics, Evolution, and Medicine, 178
Recap: Decoding the Sequence of Bases in DNA into the Sequence of Amino Acids in Protein Requires Transcription and Translation, 178
10.4. How Do Mutations in DNA Affect the Function of Genes?, 179
Mutations May Have a Variety of Effects on Protein Structure and Function, 179
A Closer Look at Protein Synthesis: A High-Energy Business, 180
Mutations Provide the Raw Material for Evolution, 180
10.5. How Are Genes Regulated?, 180
Gene Regulation in Prokaryotes, 181
Gene Regulation in Eukaryotes, 182
Scientific Inquiry: RNA—It’s Not Just a Messenger Any More, 183
Eukaryotic Cells May Regulate the Transcription of Individual Genes, Regions of Chromosomes, or Entire Chromosomes, 183
Health Watch: Sex, Aging, and Mutations, 184
Case Study Revisited: Vive la Différence!, 186
Chapter Review, 187
11. The Continuity of Life: Cellular Reproduction, 190
Case Study: How Much Is a Great Tan Worth?, 191
11.1. What Is the Role of Cellular Reproduction in the Lives of Individual Cells and Entire Organisms?, 192
The Prokaryotic Cell Cycle Consists of Growth and Binary Fission, 193
The Eukaryotic Cell Cycle Consists of Interphase and Cell Division, 194
11.2. How Is DNA in Eukaryotic Cells Organized into Chromosomes?, 195
The Eukaryotic Chromosome Consists of a Linear DNA Double Helix Bound to Proteins, 195
Eukaryotic Chromosomes Usually Occur in Homologous Pairs with Similar Genetic Information, 197
11.3. How Do Cells Reproduce by Mitotic Cell Division?, 199
During Prophase, the Chromosomes Condense and the Spindle Microtubules Form and Attach to the Chromosomes, 200
During Metaphase, the Chromosomes Align Along the Equator of the Cell, 200
During Anaphase, Sister Chromatids Separate and Are Pulled to Opposite Poles of the Cell, 200
During Telophase, Nuclear Envelopes Form Around Both Groups of Chromosomes, 200
During Cytokinesis, the Cytoplasm Is Divided Between Two Daughter Cells, 200
11.4. How Is the Cell Cycle Controlled?, 201
Scientific Inquiry: Carbon Copies—Cloning in Nature and the Lab, 202
Checkpoints Regulate Progress Through the Cell Cycle, 204
The Activities of Specific Enzymes Drive the Cell Cycle, 204
Controls over the Checkpoints, 206
11.5. Why Do So Many Organisms Reproduce Sexually?, 206
Mutations in DNA Are the Ultimate Source of Genetic Variability, 207
Sexual Reproduction May Combine Different Parental Alleles in a Single Offspring, 207
11.6. How Does Meiotic Cell Division Produce Haploid Cells?, 207
Meiosis Separates Homologous Chromosomes, Producing Haploid Daughter Nuclei, 207
Health Watch: Cancer—Mitotic Cell Division Run Amok, 208
Meiotic Cell Division Followed by Fusion of Gametes Keeps the Chromosome Number Constant from Generation to Generation, 209
Meiosis I Separates Homologous Chromosomes into Two Haploid Daughter Nuclei, 209
Meiosis II Separates Sister Chromatids into Four Daughter Nuclei, 213
11.7. When Do Mitotic and Meiotic Cell Division Occur in the Life Cycles of Eukaryotes?, 213
In Haploid Life Cycles, the Majority of the Cycle Consists of Haploid Cells, 215
In Diploid Life Cycles, the Majority of the Cycle Consists of Diploid Cells, 215
In Alternation of Generations Life Cycles, There Are Both Diploid and Haploid Multicellular Stages, 215
11.8. How Do Meiosis and Sexual Reproduction Produce Genetic Variability?, 216
Shuffling of Homologues Creates Novel Combinations of Chromosomes, 216
Crossing Over Creates Chromosomes with Novel Combinations of Genes, 217
Fusion of Gametes Adds Further Genetic Variability to the Offspring, 217
Case Study Revisited: How Much Is a Great Tan Worth?, 217
Chapter Review, 217
12. Patterns of Inheritance, 220
Case Study: Sudden Death on the Court, 221
12.1. What Is the Physical Basis of Inheritance?, 222
Genes Are Sequences of Nucleotides at Specific Locations on Chromosomes, 222
An Organism’s Two Alleles May Be the Same or Different, 222
12.2. How Did Gregor Mendel Lay the Foundations for Modern Genetics?, 222
Doing It Right: The Secrets of Mendel’s Success, 222
12.3. How Are Single Traits Inherited?, 223
The Inheritance of Dominant and Recessive Alleles on Homologous Chromosomes Can Explain the Results of Mendel’s Crosses, 224
Simple “Genetic Bookkeeping” Can Predict Genotypes and Phenotypes of Offspring, 225
Mendel’s Hypothesis Can Be Used to Predict the Outcome of New Types of Single-Trait Crosses, 226
12.4. How Are Multiple Traits Inherited?, 227
Mendel Hypothesized That Traits Are Inherited Independently, 227
In an Unprepared World, Genius May Go Unrecognized, 228
12.5. How Are Genes Located on the Same Chromosome Inherited?, 229
Genes on the Same Chromosome Tend to Be Inherited Together, 229
Recombination Can Create New Combinations of Linked Alleles, 230
12.6. How Is Sex Determined, and How Are Sex-Linked Genes Inherited?, 231
Sex-Linked Genes Are Found Only on the X or Only on the Y Chromosome, 231
12.7. Do the Mendelian Rules of Inheritance Apply to All Traits?, 233
Incomplete Dominance: The Phenotype of Heterozygotes Is Intermediate Between the Phenotypes of the Homozygotes, 233
A Single Gene May Have Multiple Alleles, 233
Scientific Inquiry: Cystic Fibrosis, 234
Many Traits Are Influenced by Several Genes, 235
Single Genes Typically Have Multiple Effects on Phenotype, 235
The Environment Influences the Expression of Genes, 237
12.8. How Are Human Genetic Disorders Investigated?, 237
12.9. How Are Human Disorders Caused by Single Genes Inherited?, 238
Some Human Genetic Disorders Are Caused by Recessive Alleles, 238
Some Human Genetic Disorders Are Caused by Dominant Alleles, 239
Some Human Genetic Disorders Are Sex-Linked, 240
12.10. How Do Errors in Chromosome Number Affect Humans?, 240
Some Genetic Disorders Are Caused by Abnormal Numbers of Sex Chromosomes, 240
Some Genetic Disorders Are Caused by Abnormal Numbers of Autosomes, 243
Case Study Revisited: Sudden Death on the Court, 244
Chapter Review, 245
13. Biotechnology, 250
Case Study: Guilty or Innocent?, 251
13.1. What Is Biotechnology?, 252
13.2. How Does DNA Recombine in Nature?, 252
Sexual Reproduction Recombines DNA, 252
Transformation May Combine DNA from Different Bacterial Species, 252
Viruses May Transfer DNA Between Species, 253
13.3. How Is Biotechnology Used in Forensic Science?, 254
The Polymerase Chain Reaction Amplifies DNA, 255
Scientific Inquiry: Hot Springs and Hot Science, 256
Gel Electrophoresis Separates DNA Segments, 256
DNA Probes Are Used to Label Specific Nucleotide Sequences, 257
Every Person Has a Unique DNA Profile, 258
13.4. How Is Biotechnology Used in Agriculture?, 258
Many Crops Are Genetically Modified, 258
Genetically Modified Plants May Be Used to Produce Medicines, 261
Genetically Modified Animals May Be Useful in Agriculture and Medicine, 261
13.5. How Is Biotechnology Used to Learn About the Human Genome?, 261
13.6. How Is Biotechnology Used for Medical Diagnosis and Treatment?, 262
DNA Technology Can Be Used to Diagnose Inherited Disorders, 262
DNA Technology Can Help to Treat Disease, 264
13.7. What Are the Major Ethical Issues of Modern Biotechnology?, 265
Links to Life: Biotechnology—from the Sublime to the Ridiculous, 266
Should Genetically Modified Organisms Be Permitted in Agriculture?, 266
Biotechnology Watch: Golden Rice, 267
Health Watch: Prenatal Genetic Screening, 268
Should the Genome of Humans Be Changed by Biotechnology?, 270
Case Study Revisited: Guilty or Innocent?, 271
Chapter Review, 272
Unit 3. Evolution and Diversity of Life, 275
14. Principles of Evolution, 276
Case Study: What Good Are Wisdom Teeth?, 277
14.1. How Did Evolutionary Thought Evolve?, 278
Early Biological Thought Did Not Include the Concept of Evolution, 278
Exploration of New Lands Revealed a Staggering Diversity of Life, 279
A Few Scientists Speculated That Life Had Evolved, 279
Fossil Discoveries Showed That Life Has Changed over Time, 279
Some Scientists Devised Nonevolutionary Explanations for Fossils, 280
Geology Provided Evidence That Earth Is Exceedingly Old, 280
Some Pre-Darwin Biologists Proposed Mechanisms for Evolution, 281
Darwin and Wallace Proposed a Mechanism of Evolution, 281
Scientific Inquiry: Charles Darwin—Nature Was His Laboratory, 282
14.2. How Do We Know That Evolution Has Occurred?, 282
Fossils Provide Evidence of Evolutionary Change over Time, 283
Comparative Anatomy Gives Evidence of Descent with Modification, 283
Embryological Similarity Suggests Common Ancestry, 286
Modern Biochemical and Genetic Analyses Reveal Relatedness Among Diverse Organisms, 286
14.3. How Does Natural Selection Work?, 288
Darwin and Wallace’s Theory Rests on Four Postulates, 288
Postulate 1: Populations Vary, 288
Postulate 2: Traits Are Inherited, 289
Postulate 3: Some Individuals Fail to Survive and Reproduce, 289
Postulate 4: Reproductive Success Is Not Random, 289
Natural Selection Modifies Populations over Time, 289
14.4. What Is the Evidence That Populations Evolve by Natural Selection?, 289
Controlled Breeding Modifies Organisms, 289
Evolution by Natural Selection Occurs Today, 290
14.5. A Postscript by Charles Darwin, 292
Case Study Revisited: What Good Are Wisdom Teeth?, 292
Chapter Review, 292
15. How Organisms Evolve, 294
Case Study: Evolution of a Menace, 295
15.1. How Are Populations, Genes, and Evolution Related?, 296
Genes and the Environment Interact to Determine Traits, 296
The Gene Pool Is the Sum of the Genes in a Population, 297
Evolution Is the Change of Allele Frequencies Within a Population, 297
The Equilibrium Population Is a Hypothetical Population in Which Evolution Does Not Occur, 297
A Closer Look: The Hardy-Weinberg Principle, 298
15.2. What Causes Evolution?, 298
Mutations Are the Original Source of Genetic Variability, 298
Gene Flow Between Populations Changes Allele Frequencies, 300
Allele Frequencies May Drift in Small Populations, 300
Mating Within a Population Is Almost Never Random, 304
All Genotypes Are Not Equally Beneficial, 304
15.3. How Does Natural Selection Work?, 306
Natural Selection Stems from Unequal Reproduction, 306
Natural Selection Acts on Phenotypes, 306
Some Phenotypes Reproduce More Successfully Than Others, 306
Earth Watch: Endangered Species—From Gene Pools to Gene Puddles, 308
Selection Can Influence Populations in Three Ways, 309
Case Study Revisited: Evolution of a Menace, 311
Chapter Review, 311
16. The Origin of Species, 314
Case Study: Lost World, 315
16.1. What Is a Species?, 316
Biologists Need a Clear Definition of Species, 316
Species Are Groups of Interbreeding Populations, 316
Appearance Can Be Misleading, 316
16.2. How Is Reproductive Isolation Between Species Maintained?, 317
Premating Isolating Mechanisms Prevent Mating Between Species, 317
Postmating Isolating Mechanisms Limit Hybrid Offspring, 319
16.3. How Do New Species Form?, 320
Geographical Separation of a Population Can Lead to Allopatric Speciation, 321
Earth Watch: Hybridization and Extinction, 322
Ecological Isolation of a Population Can Lead to Sympatric Speciation, 322
Under Some Conditions, Many New Species May Arise, 324
16.4. What Causes Extinction?, 324
Localized Distribution and Overspecialization Make Species Vulnerable in Changing Environments, 324
Interactions with Other Organisms May Drive a Species to Extinction, 325
A Closer Look: Speciation by Mutation, 326
Habitat Change and Destruction Are the Leading Causes of Extinction, 326
Evolutionary Connections: Scientists Don’t Doubt Evolution, 326
Links to Life: Biological Vanity Plates, 328
Case Study Revisited: Lost World, 328
Chapter Review, 328
17. The History of Life, 330
Case Study: Little People, Big Story, 331
17.1. How Did Life Begin?, 332
Experiments Refuted Spontaneous Generation, 332
The First Living Things Arose from Nonliving Ones, 332
RNA May Have Been the First Self-Reproducing Molecule, 334
Membrane-Like Vesicles May Have Enclosed Ribozymes, 334
But Did All This Happen?, 334
17.2. What Were the Earliest Organisms Like?, 335
The First Organisms Were Anaerobic Prokaryotes, 335
Some Organisms Evolved the Ability to Capture the Sun’s Energy, 337
Photosynthesis Increased the Amount of Oxygen in the Atmosphere, 337
Aerobic Metabolism Arose in Response to the Oxygen Crisis, 337
Some Organisms Acquired Membrane-Enclosed Organelles, 337
Scientific Inquiry: How Do We Know How Old a Fossil Is?, 338
17.3. What Were the Earliest Multicellular Organisms Like?, 339
Some Algae Became Multicellular, 340
Animal Diversity Arose in the Precambrian Era, 340
17.4. How Did Life Invade the Land?, 340
Some Plants Became Adapted to Life on Dry Land, 340
Some Animals Became Adapted to Life on Dry Land, 342
17.5. What Role Has Extinction Played in the History of Life?, 344
Evolutionary History Has Been Marked by Periodic Mass Extinctions, 345
Climate Change Contributed to Mass Extinctions, 345
Catastrophic Events May Have Caused the Worst Mass Extinctions, 346
17.6. How Did Humans Evolve?, 346
Humans Inherited Some Early Primate Adaptations for Life in Trees, 346
The Oldest Hominid Fossils Are from Africa, 347
The Earliest Hominids Could Stand and Walk Upright, 347
Several Species of Australopithecus Emerged in Africa, 349
The Genus Homo Diverged from the Australopithecines 2.5 Million Years Ago, 349
The Evolution of Homo Was Accompanied by Advances in Tool Technology, 349
Neanderthals Had Large Brains and Excellent Tools, 350
Modern Humans Emerged Less than 200,000 Years Ago, 350
Several Waves of Hominids Emigrated from Africa, 351
The Evolutionary Origin of Large Brains May Be Related to Meat Consumption, 351
The Evolutionary Origin of Human Behavior Is Highly Speculative, 353
The Cultural Evolution of Humans Now Far Outpaces Biological Evolution, 353
Case Study Revisited: Little People, Big Story, 353
Chapter Review, 354
18. Systematics: Seeking Order Amidst Diversity, 356
Case Study: Origin of a Killer, 357
18.1. How Are Organisms Named and Classified?, 358
Each Species Has a Unique, Two-Part Name, 358
Classification Originated as a Hierarchy of Categories, 358
Systematists Identify Features That Reveal Evolutionary Relationships, 358
Anatomy Plays a Key Role in Systematics, 359
Molecular Similarities Are Also Useful for Reconstructing Phylogeny, 360
18.2. What Are the Domains of Life?, 360
The Five-Kingdom System Improved Classification, 360
A Three-Domain System More Accurately Reflects Life’s History, 360
Kingdom-Level Classification Remains Unsettled, 361
A Closer Look: Reconstructing Phylogenetic Trees, 362
18.3. Why Do Classifications Change?, 364
Species Designations Change When New Information Is Discovered, 364
The Biological Species Definition Can Be Difficult or Impossible to Apply, 364
Scientific Inquiry: Molecular Genetics Reveals Evolutionary Relationships, 365
18.4. How Many Species Exist?, 366
Links to Life: Small World, 367
Case Study Revisited: Origin of a Killer, 367
Chapter Review, 368
19. The Diversity of Prokaryotes and Viruses, 370
Case Study: Agents of Death, 371
19.1. Which Organisms Make Up the Prokaryotic Domains—Bacteria and Archaea?, 372
Bacteria and Archaea Are Fundamentally Different, 372
Classification of Prokaryotes Within Each Domain Is Difficult, 372
Prokaryotes Differ in Size and Shape, 373
19.2. How Do Prokaryotes Survive and Reproduce?, 373
Some Prokaryotes Are Mobile, 373
Many Bacteria Form Films on Surfaces, 373
Protective Endospores Allow Some Bacteria to Withstand Adverse Conditions, 374
Prokaryotes Are Specialized for Specific Habitats, 374
Prokaryotes Exhibit Diverse Metabolisms, 375
Prokaryotes Reproduce by Binary Fission, 375
Prokaryotes May Exchange Genetic Material Without Reproducing, 376
19.3. How Do Prokaryotes Affect Humans and Other Eukaryotes?, 376
Prokaryotes Play Important Roles in Animal Nutrition, 376
Prokaryotes Capture the Nitrogen Needed by Plants, 376
Prokaryotes Are Nature’s Recyclers, 377
Prokaryotes Can Clean Up Pollution, 377
Some Bacteria Pose a Threat to Human Health, 377
Links to Life: Unwelcome Dinner Guests, 378
19.4. What Are Viruses, Viroids, and Prions?, 379
A Virus Consists of a Molecule of DNA or RNA Surrounded by a Protein Coat, 379
Viruses Are Parasites, 380
Some Infectious Agents Are Even Simpler Than Viruses, 381
A Closer Look: Viruses—How the Nonliving Replicate, 382
No One Is Certain How These Infectious Particles Originated, 384
Case Study Revisited: Agents of Death, 384
Chapter Review, 384
20. The Diversity of Protists, 386
Case Study: Green Monster, 387
20.1. What Are Protists?, 388
Most Protists Are Single-Celled, 389
Protists Use Diverse Modes of Nutrition, 389
Protists Use Diverse Modes of Reproduction, 389
Protists Have Significant Effects on Humans, 390
20.2. What Are the Major Groups of Protists?, 390
Excavates Lack Mitochondria, 390
Euglenozoans Have Distinctive Mitochondria, 391
Stramenopiles Include Photosynthetic and Non-Photosynthetic Organisms, 392
Alveolates Include Parasites, Predators, and Phytoplankton, 393
Cercozoans Have Thin Pseudopods and Elaborate Shells, 395
Amoebozoans Inhabit Aquatic and Terrestrial Environments, 397
Red Algae Live Primarily in Clear Tropical Oceans, 398
Green Algae Live Mostly in Ponds and Lakes, 399
Evolutionary Connections: Our Unicellular Ancestors, 400
Case Study Revisited: Green Monster, 400
Chapter Review, 400
21. The Diversity of Plants, 402
Case Study: Queen of the Parasites, 403
21.1. What Are the Key Features of Plants?, 404
Plants Have Alternating Multicellular Haploid and Diploid Generations, 404
Plants Have Multicellular, Dependent Embryos, 404
Plants Play a Crucial Ecological Role, 404
Plants Provide Humans with Necessities and Luxuries, 405
21.2. What Is the Evolutionary Origin of Plants?, 405
Green Algae Gave Rise to Plants, 405
The Ancestors of Plants Lived in Fresh Water, 405
21.3. How Have Plants Adapted to Life on Land?, 406
Plant Bodies Resist Gravity and Drying, 406
Plant Embryos Are Protected, and Plant Sex Cells May Disperse Without Water, 406
21.4. What Are the Major Groups of Plants?, 407
Bryophytes Lack Conducting Structures, 407
Vascular Plants Have Conducting Vessels That Also Provide Support, 410
The Seedless Vascular Plants Include the Club Mosses, Horsetails, and Ferns, 410
The Seed Plants Dominate the Land, Aided by Two Important Adaptations: Pollen and Seeds, 410
Gymnosperms Are Nonflowering Seed Plants, 410
Angiosperms Are Flowering Seed Plants, 416
More Recently Evolved Plants Have Smaller Gametophytes, 416
Case Study Revisited: Queen of the Parasites, 419
Chapter Review, 419
22. The Diversity of Fungi, 422
Case Study: Humongous Fungus, 423
22.1. What Are the Key Features of Fungi?, 424
Fungal Bodies Consist of Slender Threads, 424
Fungi Obtain Their Nutrients from Other Organisms, 424
Fungi Propagate by Spores, 424
Most Fungi Can Reproduce Both Sexually and Asexually, 425
22.2. What Are the Major Groups of Fungi?, 425
Chytrids Produce Swimming Spores, 425
Zygomycetes Can Reproduce by Forming Diploid Spores, 426
Ascomycetes Form Spores in a Saclike Case, 429
Basidiomycetes Produce Club-Shaped Reproductive Structures, 429
22.3. How Do Fungi Interact with Other Species?, 430
Lichens Are Formed by Fungi That Live with Photosynthetic Algae or Bacteria, 430
Mycorrhizae Are Fungi Associated with Plant Roots, 432
Endophytes Are Fungi That Live Inside Plant Stems and Leaves, 432
Some Fungi Are Important Recyclers, 432
22.4. How Do Fungi Affect Humans?, 433
Fungi Attack Plants That Are Important to People, 433
Fungi Cause Human Diseases, 434
Fungi Can Produce Toxins, 434
Many Antibiotics Are Derived from Fungi, 434
Fungi Make Important Contributions to Gastronomy, 435
Earth Watch: The Case of the Disappearing Mushrooms, 435
Evolutionary Connections: Fungal Ingenuity—Pigs, Shotguns, and Nooses, 435
Links to Life: Collect Carefully, 436
Case Study Revisited: Humongous Fungus, 437
Chapter Review, 438
23. Animal Diversity I: Invertebrates, 440
Case Study: The Search for a Sea Monster, 441
23.1. What Are the Key Features of Animals?, 442
23.2. Which Anatomical Features Mark Branch Points on the Animal Evolutionary Tree?, 442
Lack of Tissues Separates Sponges from All Other Animals, 443
Animals with Tissues Exhibit Either Radial or Bilateral Symmetry, 443
Most Bilateral Animals Have Body Cavities, 444
Bilateral Organisms Develop in One of Two Ways, 445
Protostomes Include Two Distinct Evolutionary Lines, 445
23.3. What Are the Major Animal Phyla?, 445
Sponges Have a Simple Body Plan, 445
Cnidarians Are Well-Armed Predators, 447
Flatworms Have Organs but Lack Respiratory and Circulatory Systems, 450
Annelids Are Composed of Identical Segments, 451
Most Mollusks Have Shells, 453
Links to Life: Physicians’ Assistants, 454
Arthropods Are the Dominant Animals on Earth, 456
Roundworms Are Abundant and Mostly Tiny, 462
Echinoderms Have a Calcium Carbonate Skeleton, 463
The Chordates Include the Vertebrates, 464
Case Study Revisited: The Search for a Sea Monster, 464
Chapter Review, 465
24. Animal Diversity II: Vertebrates, 468
Case Study: Fish Story, 469
24.1. What Are the Key Features of Chordates?, 470
All Chordates Share Four Distinctive Features, 470
The Invertebrate Chordates Live in the Seas, 471
Vertebrates Have a Backbone, 471
24.2. What Are the Major Groups of Vertebrates?, 472
Some Vertebrates Lack Jaws, 472
Jawed Fishes Rule Earth’s Waters, 473
Amphibians Live a Double Life, 475
Earth Watch: Frogs in Peril, 476
Reptiles and Birds Are Adapted for Life on Land, 477
Mammals Provide Milk to Their Offspring, 480
Evolutionary Connections: Are Humans a Biological Success?, 482
Links to Life: Do Animals Belong in Laboratories?, 483
Case Study Revisited: Fish Story, 484
Chapter Review, 484
Unit 4. Behavior and Ecology, 487
25. Animal Behavior, 488
Case Study: Sex and Symmetry, 489
25.1. How Do Innate and Learned Behaviors Differ?, 490
Innate Behaviors Can Be Performed Without Prior Experience, 490
Learned Behaviors Are Modified by Experience, 490
There Is No Sharp Distinction Between Innate and Learned Behaviors, 492
25.2. How Do Animals Communicate?, 495
Visual Communication Is Most Effective over Short Distances, 495
Communication by Sound Is Effective over Longer Distances, 496
Chemical Messages Persist Longer but Are Hard to Vary, 496
Communication by Touch Helps Establish Social Bonds, 497
25.3. How Do Animals Compete for Resources?, 497
Aggressive Behavior Helps Secure Resources, 497
Dominance Hierarchies Help Manage Aggressive Interactions, 498
Animals May Defend Territories That Contain Resources, 499
25.4. How Do Animals Find Mates?, 501
Signals Encode Sex, Species, and Individual Quality, 501
25.5. What Kinds of Societies Do Animals Form?, 502
Group Living Has Advantages and Disadvantages, 502
The Extent of Sociality Varies Among Species, 502
Forming Groups with Relatives Fosters the Evolution of Altruism, 503
Honeybees Live Together in Rigidly Structured Societies, 504
Naked Mole Rats Form a Complex Vertebrate Society, 505
25.6. Can Biology Explain Human Behavior?, 506
The Behavior of Newborn Infants Has a Large Innate Component, 506
Young Humans Acquire Language Easily, 506
Behaviors Shared by Diverse Cultures May Be Innate, 507
Humans May Respond to Pheromones, 507
Studies of Twins Reveal Genetic Components of Behavior, 508
Biological Investigation of Human Behavior Is Controversial, 508
Evolutionary Connections: Why Do Animals Play?, 508
Case Study Revisited: Sex and Symmetry, 509
Chapter Review, 510
26. Population Growth and Regulation, 512
Case Study: The Mystery of Easter Island, 513
26.1. How Does Population Size Change?, 514
Biotic Potential Can Produce Exponential Growth, 514
26.2. How Is Population Growth Regulated?, 515
Exponential Growth Occurs Only Under Special Conditions, 515
Environmental Resistance Limits Population Growth, 518
Scientific Inquiry: Cycles in Predator and Prey Population, 519
26.3. How Are Populations Distributed in Space and Time?, 524
Populations Exhibit Different Spatial Distributions, 524
Survivorship in Populations Follows Three Basic Patterns, 525
26.4. How Is the Human Population Changing?, 526
Demographers Track Changes in Human Populations, 526
The Human Population Continues to Grow Rapidly, 526
Technological Advances Have Increased Earth’s Capacity to Support People, 526
The Demographic Transition Helps Stabilize Populations, 527
Earth Watch: Have We Exceeded Earth’s Carrying Capacity?, 528
Population Growth Is Unevenly Distributed, 528
The Current Age Structure of a Population Predicts Its Future Growth, 529
Fertility in Europe Is Below Replacement Level, 530
The U.S. Population Is Growing Rapidly, 532
Case Study Revisited: The Mystery of Easter Island, 532
Links to Life: Treading Lightly—How Big Is Your “Footprint”?, 533
Chapter Review, 533
27. Community Interactions, 536
Case Study: Invasion of the Zebra Mussels, 537
27.1. Why Are Community Interactions Important?, 538
27.2. What Is the Relationship Between the Ecological Niche and Competition?, 538
The Ecological Niche Defines the Place and Role of Each Species in Its Ecosystem, 538
Competition Occurs Whenever Two Organisms Attempt to Use the Same, Limited Resources, 538
Adaptations Reduce the Overlap of Ecological Niches Among Coexisting Species, 539
Interspecific Competition May Reduce the Population Size and Distribution of Each Species, 540
Competition Within a Species Is a Major Factor Controlling Population Size, 540
27.3. What Are the Results of Interactions Between Predators and Their Prey?, 540
Earth Watch: Invasive Species Disrupt Community Interactions, 541
Predator-Prey Interactions Shape Evolutionary Adaptations, 543
27.4. What Is Symbiosis?, 547
Parasitism Harms, but Does Not Immediately Kill, the Host, 547
In Mutualistic Interactions, Both Species Benefit, 547
Scientific Inquiry: Ants and Acacias—An Advantageous Association, 549
27.5. How Do Keystone Species Influence Community Structure?, 549
27.6. Succession: How Do Community Interactions Cause Change over Time?, 550
There Are Two Major Forms of Succession: Primary and Secondary, 550
Succession Also Occurs in Ponds and Lakes, 553
Succession Culminates in the Climax Community, 553
Some Ecosystems Are Maintained in a Subclimax State, 553
Evolutionary Connections: Is Camouflage Splitting a Species?, 554
Case Study Revisited: Invasion of the Zebra Mussels, 555
Chapter Review, 555
28. How Do Ecosystems Work?, 558
Case Study: When the Salmon Return, 559
28.1. What Are the Pathways of Energy and Nutrients?, 560
28.2. How Does Energy Flow Through Communities?, 561
Energy Enters Communities Through Photosynthesis, 561
Energy Is Passed from One Trophic Level to Another, 562
Energy Transfer Through Trophic Levels Is Inefficient, 564
Earth Watch: Food Chains Magnify Toxic Substances, 566
28.3. How Do Nutrients Move Within and Among Ecosystems?, 567
Carbon Cycles Through the Atmosphere, Oceans, and Communities, 567
The Major Reservoir for Nitrogen Is the Atmosphere, 568
The Phosphorus Cycle Has No Atmospheric Component, 569
Most Water Remains Chemically Unchanged During the Hydrologic Cycle, 570
28.4. What Causes “Acid Rain”?, 571
Overloading the Nitrogen and Sulfur Cycles Causes Acid Deposition, 571
Acid Deposition Damages Life in Lakes and Forests, 572
The Clean Air Act Has Significantly Reduced Sulfur, but Not Nitrogen, Emissions, 572
28.5. What Causes Global Warming?, 572
Interfering with the Carbon Cycle Contributes to Global Warming, 572
Greenhouse Gases Trap Heat in the Atmosphere, 573
Global Warming Will Have Severe Consequences, 574
How Are People Responding to the Threat?, 575
Earth Watch: Poles in Peril, 576
Links to Life: Making a Difference, 577
Case Study Revisited: When the Salmon Return, 577
Chapter Review, 578
29. Earth’s Diverse Ecosystems, 580
Case Study: Wings of Hope, 581
29.1. What Factors Influence Earth’s Climate?, 582
Both Climate and Weather Are Driven by the Sun, 582
Earth’s Physical Features Also Influence Climate, 582
29.2. What Conditions Does Life Require?, 585
29.3. How Is Life on Land Distributed?, 585
Earth Watch: The Ozone Hole—A Puncture in Our Protective Shield, 586
Terrestrial Biomes Support Characteristic Plant Communities, 587
Links to Life: Crave Chocolate and Save Rain Forests?, 591
Rainfall and Temperature Limit the Plant Life of a Biome, 598
29.4. How Is Life in Water Distributed?, 598
Freshwater Ecosystems Include Lakes, Streams, and Rivers, 598
Marine Ecosystems Cover Much of Earth, 601
Case Study Revisited: Wings of Hope, 607
Chapter Review, 607
30. Conserving Life on Earth, 610
Case Study: Back from Extinction, 611
30.1. What Is Biodiversity, and Why Should We Care About It?, 612
Ecosystem Services: Practical Uses for Biodiversity, 612
Ecological Economics Recognizes the Monetary Value of Ecosystem Services, 614
30.2. Is Earth’s Biodiversity Diminishing?, 615
Extinction Is a Natural Process, but Rates Have Risen Dramatically, 615
Earth Watch: Restoring the Everglades, 616
Increasing Numbers of Species Are Threatened with Extinction, 616
30.3. What Are The Major Threats to Biodiversity?, 617
Humanity Is Depleting Earth’s “Ecological Capital”, 617
Human Activities Threaten Biodiversity in Several Important Ways, 618
Earth Watch: Tangled Troubles—Logging, Fishing, and Bushmeat, 618
Earth Watch: Saving Sea Turtles, 621
30.4. How Can Conservation Biology Help to Preserve Biodiversity?, 623
The Foundations of Conservation Biology, 623
Conservation Biology Is an Integrated Science, 623
Conserving Wild Ecosystems, 623
Earth Watch: Restoring a Keystone Predator, 624
30.5. Why Is Sustainability the Key to Conservation?, 625
Sustainable Living and Sustainable Development Promote Long-Term Ecological and Human Well-Being, 625
Biosphere Reserves Provide Models for Conservation and Sustainable Development, 626
Sustainable Agriculture Helps Preserve Natural Communities, 627
The Future Is in Your Hands, 627
Earth Watch: Preserving Biodiversity with Shade-Grown Coffee, 629
Case Study Revisited: Back from Extinction, 629
Links to Life: What Can Individuals Do?, 630
Chapter Review, 631
Appendix I. Metric System Conversions, 633
Appendix II. Classification of Major Groups of Organisms, 634
Appendix III. Biological Vocabulary: Common Roots, Prefixes, and Suffixes, 635
Glossary, G1
Answers to Figure Caption Questions, A1
Photo Credits, P1
Index, I1

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