Bibliographic record and links to related information available from the Library of Congress catalog.
Note: Contents data are machine generated based on pre-publication provided by the publisher. Contents may have variations from the printed book or be incomplete or contain other coding.
Contents Preface 000 Chapter 1 An Introduction to Life on Earth 000 1.1 Why Study Biology? 1 Biology Helps You Understand Your Body 1 Biology Helps You Become an Informed Citizen 1 Biology Can Open Career Opportunities 2 Biology Can Enrich Your Appreciation of the World 2 1.2 How Do Biologists Study Life? The Scientific Method Is the Basis for Scientific Inquiry 3 Scientific Inquiry: Controlled Experiments, Then and Now 4 Life Can Be Studied at Different Levels of Organization 6 Science Is a Human Endeavor 7 Scientific Theories Have Been Thoroughly Tested 8 1.3 What Is Life? 8 Living Things Are Both Complex and Organized 8 Living Things Grow and Reproduce 9 Living Things Respond to Stimuli 9 Living Things Acquire and Use Materials and Energy 9 Living Things Use DNA to Store Information 10 1.4 Why Is Life So Diverse? 10 Evolution Accounts for Both Life's Unity and Its Diversity 10 Natural Selection Causes Evolution 10 Earth Watch: Why Preserve Biodiversity? 4 Life's Diversity Is Currently Threatened 11 Links to Life 12 Chapter Review 12 UNIT ONE Life of a Cell 15 Chapter 2 Atoms, Molecules, and Life 16 Improving on Nature? 17 2.1 What Are Atoms? 18 Atoms Are Composed of Even Smaller Particles 18 Electrons Orbit the Nucleus, Forming Electron Shells 18 2.2 How Do Atoms Form Molecules? 19 Atoms Interact When There Are Vacancies in Their Outermost Electron Shells 19 Charged Atoms Interact to Form Ionic Bonds 20 Uncharged Atoms Share Electrons to Form Covalent Bonds 20 Hydrogen Bonds Form between Molecules with Polar Covalent Bonds 21 2.3 Why Is Water So Important to Life? 22 Water Interacts with Many Other Molecules 22 Many Molecules Dissolve Easily in Water 22 Water Molecules Tend to Stick Together 22 Water Can Form Ions 23 2.4 Why Is Carbon So Important to Life? 24 2.5 How Are Biological Molecules Joined Together or Broken Apart? 25 2.6 What Are Carbohydrates? 26 A Variety of Simple Sugars Occur in Organisms 27 Disaccharides Store Energy and Serve As Building Blocks 27 Polysaccharides Store Energy and Provide Support 27 2.7 What Are Lipids? 28 Oils, Fats, and Waxes Contain Only Carbon, Hydrogen, and Oxygen 29 Health Watch: Cholesterol; Friend and Foe 30 Phospholipids Have Water-Soluble Heads and Water-Insoluble Tails 30 Steroids Consist of Four Carbon Rings Fused Together 30 2.8 What Are Proteins? 30 Proteins Are Formed from Chains of Amino Acids 31 Earth Watch: Deadly Elements 32 Amino Acids Join to Form Chains by Dehydration Synthesis 32 Three-Dimensional Shapes Give Proteins Their Functions 32 2.9 What Are Nucleic Acids? 33 DNA and RNA, the Molecules of Heredity, Are Nucleic Acids 34 Other Nucleotides Perform Other Functions 34 Improving on Nature? Revisited 34 Links to Life 35 Chapter Review 35 Chapter 3 Cell Membrane Structure and Function 38 Can Teens Have Heart Attacks? 39 1 What Does the Plasma Membrane Do? 40 2 What Is the Structure of the Plasma Membrane? 40 Membranes Are "Fluid Mosaics" 40 The Phospholipid Bilayer Is the Fluid Portion of the Membrane 40 A Mosaic of Proteins Is Embedded in the Membrane 41 3 How Does the Plasma Membrane Play Its Gatekeeper Role? 42 The Phospholipid Bilayer Blocks the Passage of Most Molecules 42 The Embedded Proteins Selectively Transport, Respond to, and Recognize Molecules 42 4 What Is Diffusion? 42 Molecules in Fluids Move in Response to Gradients 43 A Drop of Dye in Water Illustrates Diffusion 43 Summing Up: The Principles of Diffusion 44 5 What Is Osmosis? 44 Summing Up: The Principles of Osmosis 45 6 How Do Diffusion and Osmosis Affect Transport Across the Plasma Membrane? 45 Plasma Membranes Are Selectively Permeable 45 Some Molecules Move Across Membranes by Simple Diffusion 45 Other Molecules Cross the Membrane by Facilitated Diffusion 46 Water Can Move Across Plasma Membranes by Osmosis 47 7 How Do Molecules Move Against a Concentration Gradient? 47 Active Transport Uses Energy to Move Molecules against Their Concentration Gradients 48 Membrane Proteins Regulate Active Transport 48 Cells Engulf Particles or Fluids by Endocytosis 48 Exocytosis Moves Material out of the Cell 48 Some Plasma Membranes Are Surrounded by Cell Walls 48 Evolutionary Connections: Caribou Legs and Membrane Diversity 50 Can Teens Have Heart Attacks? Revisited 50 Links to Life 51 Chapter Review 51 Chapter 4 Cell Structure and Function 54 Can Lost Limbs Grow Back? 55 1 What Features Are Shared by All Cells? 56 Cells Are Enclosed by a Plasma Membrane 56 Cells Use DNA as a Hereditary Blueprint 56 Cells Contain Cytoplasm 56 Cells Obtain Energy and Nutrients from Their Environment 56 Cell Function Limits Cell Size 56 Scientific Inquiry: The Search for the Cell 58 2 How Do Prokaryotic and Eukaryotic Cells Differ? 60 3 What Are the Main Features of Eukaryotic Cells? 61 4 What Role Does the Nucleus Play? 62 The Nuclear Envelope Controls Passage of Materials 62 The Nucleus Contains Chromosomes 62 Ribosome Components Are Made at the Nucleolus 62 5 What Roles Do Membranes Play in Eukaryotic Cells? 63 The Plasma Membrane Isolates the Cell and Helps It Interact with Its Environment 63 The Endoplasmic Reticulum Forms Channels within the Cytoplasm 63 The Golgi Complex Sorts, Chemically Alters, and Packages Important Molecules 64 We Can Follow the Travels of a Secreted Protein 65 Lysosomes Serve as the Cell's Digestive System 65 6 Which Other Structures Play Key Roles in Eukaryotic Cells? 65 Vacuoles Regulate Water and Store Substances 65 Mitochondria Extract Energy from Food Molecules 65 Chloroplasts Capture Solar Energy 66 The Cytoskeleton Provides Shape, Support, and Movement 66 Cilia and Flagella Move the Cell or Move Fluid Past the Cell 66 7 What Are the Features of Prokaryotic Cells? 67 Can Lost Limbs Grow Back? Revisited 68 Links to Life 68 Chapter Review 68 Chapter 5 Energy Flow in the Life of a Cell 72 A Missing Molecule Makes Mischief 73 1 What Is Energy? 74 Energy Cannot Be Created or Destroyed 74 Energy Tends to Become Distributed Evenly 74 Matter Tends to Become Less Organized 74 Living Things Use the Energy of Sunlight to Create Low-Entropy Conditions 75 2 How Does Energy Flow in Chemical Reactions? 75 Exergonic Reactions Release Energy 75 Endergonic Reactions Require an Input of Energy 76 All Reactions Require an Initial Input of Energy 76 Exergonic Reactions May Be Linked with Endergonic Reactions 76 3 How Is Energy Carried between Coupled Reactions? 77 ATP Is the Principal Energy Carrier in Cells 77 Electron Carriers Also Transport Energy within Cells 78 4 How Do Cells Control Their Metabolic Reactions? 78 At Body Temperatures, Many Spontaneous Reactions Proceed Too Slowly to Sustain Life 78 Catalysts Reduce Activation Energy 79 Enzymes Are Biological Catalysts 79 The Structure of Enzymes Allows Them to Catalyze Specific Reactions 79 The Activity of Enzymes Is Influenced by Their Environment 80 A Missing Molecule Makes Mischief Revisited 81 Links to Life 81 Chapter Review 81 Chapter 6 Capturing Solar Energy: Photosynthesis 84 Did the Dinosaurs Die from a Lack of Sunlight? 85 1 What Is Photosynthesis? 86 Photosynthesis Converts Carbon Dioxide and Water to Glucose 87 Plant Photosynthesis Takes Place in Leaves 87 Leaf Cells Contain Chloroplasts 87 Photosynthesis Consists of Light-Dependent and Light-Independent Reactions 87 2 How Is Light Energy Converted to Chemical Energy? 88 Light Energy Is First Captured by Pigments in Chloroplasts 88 The Light-Dependent Reactions Generate Energy-Carrier Molecules 88 Splitting Water Maintains the Flow of Electrons Through the Photosystems 89 Summing Up: Light-Dependent Reactions 90 3 How Is Chemical Energy Stored in Glucose Molecules? 90 The C3 Cycle Captures Carbon Dioxide 90 Carbon Fixed During the C3 Cycle Is Used to Synthesize Glucose 91 Summing Up: Light-Independent Reactions 91 4 What Is the Relationship Between Light-Dependent and Light-Independent Reactions? 91 5 How Does the Need to Conserve Water Affect Photosynthesis? 91 Earth Watch: Can Forests Prevent Global Warming? 92 When Stomata Are Closed to Conserve Water, Wasteful Photorespiration Occurs 92 An Alternative Pathway Reduces Photorespiration in C4 Plants 93 C3 and C4 Plants Are Each Adapted to Different Environmental Conditions 94 Did the Dinosaurs Die from a Lack of Sunlight? Revisited 94 Links to Life 94 Chapter Review 95 Chapter 7 Harvesting Energy: Glycolysis and Cellular Respiration 98 When Athletes Boost Their Blood Counts: Do Cheaters Prosper? 99 1 What Is the Source of a Cell's Energy? 100 Glucose Is a Key Energy-Storage Molecule 100 Photosynthesis Is the Ultimate Source of Cellular Energy 100 Glucose Metabolism and Photosynthesis Are Complementary Processes 100 2 How Do Cells Harvest Energy from Glucose? 101 3 What Happens During Glycolysis? 101 Activation Consumes Energy 102 Energy Harvest Yields Energy-Carrier Molecules 102 Summing Up: Glycolysis 102 4 What Happens During Cellular Respiration? 102 The Krebs Cycle Breaks Down Pyruvate in the Mitochondrial Matrix 104 Summing Up: The Mitochondrial Matrix Reactions 104 Energetic Electrons Are Carried to Electron Transport Chains 104 Energy from a Hydrogen-Ion Gradient Is Used to Produce ATP 105 Summing Up: Electron Transport and Chemiosmosis 105 5 What Happens During Fermentation? 106 Some Cells Ferment Pyruvate to Form Alcohol 106 Other Cells Ferment Pyruvate to Lactate 106 Fermentation's Effects Limit Human Muscle Performance 107 When Athletes Boost Their Blood Counts: Do Cheaters Prosper? Revisited 107 Links to Life 108 Chapter Review 108 UNIT TWO INHERITANCE 111 Chapter 8 DNA: The Molecule of Heredity 112 Modern Showdown in the Old West 113 1 What Are Genes Made Of? 114 2 What Is the Structure of DNA? 114 DNA Is Composed of Four Different Subunits 114 A DNA Molecule Contains Two Nucleotide Strands 115 Hydrogen Bonds Hold the Two DNA Strands Together in a Double Helix 115 Scientific Inquiry: The Discovery of the Double Helix 116 3 How Does DNA Encode Information? 116 4 How Is DNA Copied? 117 Why Does DNA Need to Be Copied? 117 DNA Is Copied before Cell Division 117 DNA Replication Produces Two DNA Double Helixes, Each with One Original Strand and One New Strand 117 Proofreading Produces Almost Error-Free Replication of DNA 118 Mistakes Do Happen 118 5 What Are the Mechanisms of DNA Replication? 118 DNA Helicase Separates the Parental Strands 118 DNA Polymerase Synthesizes New DNA Strands 120 DNA Ligase Joins Together Segments of DNA 120 Modern Showdown in the Old West Revisited 121 Links to Life 121 Chapter Review 121 Chapter 9 Gene Expression and Regulation 124 Snakes and Snails and Puppy Dogs' Tails 125 9.1 How Is the Information in DNA Used in a Cell? 126 Most Genes Contain Information for the Synthesis of a Single Protein 126 RNA Intermediaries Carry the Genetic Information for Protein Synthesis 126 Overview: Genetic Information Is Transcribed into RNA, Then Translated into Protein 126 9.2 What Is the Genetic Code? 127 A Sequence of Three Bases Codes for an Amino Acid 127 9.3 How Is the Information in a Gene Transcribed into RNA? 129 Transcription Begins When RNA Polymerase Binds to the Promoter of a Gene 129 Elongation Generates a Growing Strand of RNA 129 Transcription Stops When RNA Polymerase Reaches the Termination Signal 129 Transcription Is Selective 130 9.4 What Are the Functions of RNA? 130 Messenger RNA Carries the Code for a Protein from the Nucleus to the Cytoplasm 130 Ribosomal RNA and Proteins Form Ribosomes 131 Transfer RNA Molecules Carry Amino Acids to the Ribosomes 131 9.5 How Is the Information in Messenger RNA Translated into Protein? 131 Translation Begins When tRNA and mRNA Bind to a Ribosome 131 Elongation Generates a Growing Chain of Amino Acids 133 A Stop Codon Signals Termination 133 Summing Up: Transcription and Translation 133 9.6 How Do Mutations Affect Gene Function? 133 Mutations May Be Nucleotide Substitutions, Insertions, or Deletions 134 Mutations Affect Proteins in Different Ways 134 Mutations Are the Raw Material for Evolution 135 9.7 Are All Genes Expressed? 136 Gene Expression Differs from Cell to Cell and over Time 136 Environmental Cues Influence Gene Expression 136 9.8 How Is Gene Expression Regulated? 136 Regulatory Proteins That Bind to Promoters Alter the Transcription of Genes 136 Health Watch: Mutations and Gender 137 Some Regions of Chromosomes Are Condensed and Not Normally Transcribed 137 Entire Chromosomes May Be Inactivated and Not Transcribed 137 Snakes and Snails and Puppy Dogs' Tails Revisited 138 Links to Life 138 Chapter Review 139 Chapter 10 The Continuity of Life: How Cells Reproduce 142 Cloning Controversy 143 10.1 Why Do Cells Divide? 144 Cell Division Is Required for Growth and Development 144 Cell Division Is Required for Asexual Reproduction 144 Meiotic Cell Division Is Required for Sexual Reproduction 144 10.2 What Occurs During the Prokaryotic Cell Cycle? 146 10.3 What Occurs During the Eukaryotic Cell Cycle? 146 There Are Two Types of Division in Eukaryotic Cells: Mitotic Cell Division and Meiotic Cell Division 147 The Life Cycles of Eukaryotic Organisms Include Both Mitotic and Meiotic Cell Division 147 10.4 How Is DNA in Eukaryotic Cells Organized into Chromosomes? 148 Eukaryotic Chromosomes Consist of DNA Bound to Proteins 148 A Chromosome Contains Many Genes 148 Duplicated Chromosomes Separate During Cell Division 149 Eukaryotic Chromosomes Usually Occur in Pairs 149 10.5 How Does Mitotic Cell Division Produce Genetically Identical Daughter Cells? 150 During Prophase, the Chromosomes Condense and Are Captured by the Spindle 151 During Metaphase, the Chromosomes Line Up along the Equator of the Cell 152 During Anaphase, Sister Chromatids Separate and Move to Opposite Poles of the Cell 153 Scientific Inquiry: Carbon Copies: Cloning in Nature and in the Laboratory 154 During Telophase, Nuclear Envelopes Form Around Both Groups of Chromosomes 156 During Cytokinesis, the Cytoplasm Is Divided between Two Daughter Cells 156 10.6 How Does Meiotic Cell Division Produce Haploid Cells? 156 Meiosis Produces Four Haploid Daughter Nuclei 157 Meiosis I Separates Homologous Chromosomes into Two Haploid Daughter Nuclei 157 Meiosis II Separates Sister Chromatids into Four Haploid Daughter Cells 157 10.7 How Do Meiotic Cell Division and Sexual Reproduction Produce Genetic Variability? 160 Shuffling of Homologues Creates Novel Combinations of Chromosomes 160 Crossing Over Creates Chromosomes with Novel Combinations of Genetic Material 162 Fusion of Gametes Creates Genetically Variable Offspring 162 Cloning Controversy Revisited 162 Links to Life 163 Chapter Review 163 Chapter 11 Patterns of Inheritance 166 Sudden Death on the Court 167 11.1 What Is the Physical Basis of Inheritance? 168 Genes Are Sequences of Nucleotides at Specific Locations on Chromosomes 168 An Organism's Two Alleles May Be the Same or Different 168 11.2 How Were the Principles of Inheritance Discovered? 168 Doing It Right: The Secrets of Mendel's Success 169 11.3 How Are Single Traits Inherited? 169 The Pattern of Inheritance of Single Traits Can Be Explained by the Inheritance of Alleles of a Single Gene 170 Simple "Genetic Bookkeeping" Can Predict Genotypes and Phenotypes of Offspring 172 Mendel's Hypothesis Can Predict the Outcome of New Types of Single-Trait Crosses 173 11.4 How Are Multiple Traits Inherited? 173 Mendel Concluded That Multiple Traits Are Inherited Independently 173 In an Unprepared World, Genius May Go Unrecognized 174 11.5 How Are Genes Located on the Same Chromosome Inherited? 174 Genes on the Same Chromosome Tend to Be Inherited Together 175 Crossing Over Can Create New Combinations of Linked Alleles 175 11.6 How Is Sex Determined? 175 11.7 How Are Sex-Linked Genes Inherited? 176 11.8 Do the Mendelian Rules of Inheritance Apply to All Traits? 176 Incomplete Dominance Produces Intermediate Phenotypes 176 A Single Gene May Have Multiple Alleles 177 A Single Trait May Be Influenced by Several Genes 177 A Single Gene May Have Multiple Effects on Phenotype 178 The Environment Influences the Expression of Genes 178 Scientific Inquiry: Cystic Fibrosis 179 11.9 How Are Human Genetic Disorders Investigated? 180 11.10 How Are Single-Gene Disorders Inherited? 180 Some Human Genetic Disorders Are Caused by Recessive Alleles 180 Some Human Genetic Disorders Are Caused by Dominant Alleles 181 Some Human Genetic Disorders Are Sex-Linked 182 11.11 How Do Errors in Chromosome Number Affect Humans? 182 Abnormal Numbers of Sex Chromosomes Cause Some Disorders 183 Abnormal Numbers of Autosomes Cause Some Disorders 184 Sudden Death on the Court Revisited 186 Links to Life 186 Chapter Review 187 Chapter 12 Biotechnology 192 Guilty or Innocent? 193 12.1 What Is Biotechnology? 194 12.2 How Does DNA Recombine in Nature? 194 Sexual Reproduction Recombines DNA 195 Transformation May Combine DNA from Different Bacterial Species 195 Viruses May Transfer DNA between Species 196 12.3 How Is Biotechnology Used in Forensics? 197 The Polymerase Chain Reaction Amplifies DNA 197 Scientific Inquiry: Hot Springs and Hot Science 198 Differences in Short DNA Segments Can Identify Individuals 198 Gel Electrophoresis Separates DNA Segments 199 DNA Probes Are Used to Label Specific Nucleotide Sequences 199 A DNA Fingerprint Is Unique to Each Person 200 12.4 How Is Biotechnology Used in Agriculture? 200 Many Crops Are Genetically Modified 200 Genetically Modified Animals May Be Useful in Agriculture and Medicine 201 12.5 How Is Biotechnology Used to Learn About the Human Genome? 202 Biotechnology Watch: Bonanza from the Sea or Frankenfish? 202 12.6 How Is Biotechnology Used for Medical Diagnosis and Treatment? 203 DNA Technology Can Be Used to Diagnose Inherited Disorders 203 DNA Technology Can Be Used to Treat Disease 204 Health Watch: Prenatal Genetic Screening 206 12.7 What Are the Major Ethical Issues of Biotechnology? 207 Should Genetically Modified Organisms Be Permitted in Agriculture? 207 Should the Human Genome Be Changed by Biotechnology? 209 Guilty or Innocent? Revisited 210 Links to Life 210 Chapter Review 210 UNIT THREE Evolution 213 Chapter 13 Principles of Evolution 214 What Good Are Wisdom Teeth? 215 13.1 How Did Evolutionary Thought Evolve? 216 Early Biological Thought Did Not Include the Concept of Evolution 216 Exploration of New Lands Revealed a Staggering Diversity of Life 216 A Few Scientists Speculated That Life Had Evolved 216 Fossil Discoveries Showed That Life Has Changed over Time 217 Some Scientists Devised Nonevolutionary Explanations for Fossils 218 Geology Provided Evidence That Earth Is Exceedingly Old 219 Some Pre-Darwin Biologists Proposed Mechanisms for Evolution 219 Darwin and Wallace Proposed a Mechanism of Evolution 219 13.2 How Does Natural Selection Work? 220 Scientific Inquiry: Charles Darwin; Nature Was His Laboratory 222 Modern Genetics Confirmed Darwin's Assumption of Inheritance 223 Natural Selection Modifies Populations over Time 223 13.3 How Do We Know That Evolution Has Occurred? 223 Fossils Provide Evidence of Evolutionary Change over Time 223 Comparative Anatomy Gives Evidence of Descent with Modification 224 Embryological Similarity Suggests Common Ancestry 226 Modern Biochemical and Genetic Analyses Reveal Relatedness among Diverse Organisms 227 13.4 What Is the Evidence That Populations Evolve by Natural Selection? 228 Controlled Breeding Modifies Organisms 228 Evolution by Natural Selection Occurs Today 228 13.5 A Postscript by Charles Darwin 230 What Good Are Wisdom Teeth? Revisited 231 Links to Life 231 Chapter Review 231 Chapter 14 How Populations Evolve 234 Evolution of a Menace 235 14.1 How Are Populations, Genes, and Evolution Related? 236 Genes and the Environment Interact to Determine Traits 236 The Gene Pool Is the Sum of the Genes in a Population 236 Evolution Is the Change of Allele Frequencies within a Population 237 The Equilibrium Population Is a Hypothetical Population in Which Evolution Does Not Occur 237 14.2 What Causes Evolution? 238 Mutations Are the Original Source of Genetic Variability 238 Allele Frequencies May Drift in Small Populations 238 Genotypes Are Not All Equally Beneficial 241 14.3 How Does Natural Selection Work? 242 Natural Selection Stems from Unequal Reproduction 242 Natural Selection Acts on Phenotypes 243 Some Phenotypes Reproduce More Successfully Than Others 243 14.4 What Is a Species? 245 Biologists Need a Clear Definition of Species 245 Species Are Groups of Interbreeding Populations 245 Appearance Can Be Misleading 246 14.5 How Do New Species Form? 246 Geographical Separation of a Population Can Lead to Speciation 246 Under Some Conditions, Many New Species May Arise 247 14.6 How Is Reproductive Isolation between Species Maintained? 247 Premating Isolating Mechanisms Prevent Mating between Species 248 Biotechnology Watch: Cloning Endangered Species 249 Postmating Isolating Mechanisms Limit Hybrid Offspring 249 14.7 What Causes Extinction? 250 Interactions with Other Species May Drive a Species to Extinction 250 Earth Watch: Endangered Species: From Gene Pools to Gene Puddles 251 Habitat Change and Destruction Are the Leading Causes of Extinction 251 Evolutionary Connections: Scientists Don't Doubt Evolution 252 Evolution of a Menace Revisited 252 Links to Life 252 Chapter Review 253 Chapter 15 The History of Life on Earth 256 Dinosaurs Singing in the Backyard? 257 15.1 How Did Life Begin? 258 Experiments Refuted Spontaneous Generation 258 The First Living Things Arose from Nonliving Ones 258 Organic Molecules Can Form Spontaneously under Prebiotic Conditions 259 Organic Molecules Can Accumulate under Prebiotic Conditions 259 Organic Molecules May Have Become Concentrated in Tidal Pools 259 RNA May Have Been the First Self-Reproducing Molecule 260 Membrane-Like Microspheres May Have Enclosed Ribozymes 261 But Did All This Happen? 261 15.2 What Were the Earliest Organisms Like? 262 The First Organisms Were Anaerobic Prokaryotes 262 Some Organisms Evolved the Ability to Capture the Sun's Energy 262 Photosynthesis Increased the Amount of Oxygen in the Atmosphere 262 Scientific Inquiry: How Do We Know How Old a Fossil Is? 264 Aerobic Metabolism Arose in Response to the Oxygen Crisis 265 Some Organisms Acquired Membrane-Enclosed Organelles 265 15.3 What Were the Earliest Multicellular Organisms Like? 266 Some Algae Became Multicellular 266 Animal Diversity Arose in the Precambrian Era 266 15.4 How Did Life Invade the Land? 268 Some Plants Became Adapted to Life on Dry Land 268 Some Animals Became Adapted to Life on Dry Land 269 15.5 What Role Has Extinction Played in the History of Life? 271 Evolutionary History Has Been Marked by Periodic Mass Extinctions 272 Climate Change Contributed to Mass Extinctions 272 Catastrophic Events May Have Caused the Worst Mass Extinctions 272 15.6 How Did Humans Evolve? 273 Humans Inherited Some Early Primate Adaptations for Life in Trees 273 The Oldest Hominid Fossils Are from Africa 274 The Earliest Hominids Could Stand and Walk Upright 274 Several Species of Australopithecus Emerged in Africa 276 The Genus Homo Diverged from the Australopithecines 2.5 Million Years Ago 276 The Evolution of Homo Was Accompanied by Advances in Tool Technology 276 Neanderthals Had Large Brains and Excellent Tools 277 Modern Humans Emerged Only 150,000 Years Ago 277 Cro-Magnons and Neanderthals Lived Side by Side 278 Dinosaurs Singing in the Backyard Revisited 278 Links to Life 279 Chapter Review 279 Chapter 16 The Diversity of Life 282 An Unsolved Mystery: How Many Species Are There? 283 16.1 How Are Organisms Named and Classified? 284 Each Species Has a Unique, Two-Part Name 284 Classification Originated As a Hierarchy of Categories 284 Biologists Identify Features That Reveal Evolutionary Relationships 285 Anatomy Plays a Key Role in Classification 285 Molecular Similarities Are Also Useful for Classification 286 16.2 What Are the Domains of Life? 286 The Five-Kingdom System Improved Classification 286 A Three-Domain System More Accurately Reflects Life's History 286 Kingdom-Level Classification Remains Unsettled 287 16.3 Bacteria and Archaea 287 Bacteria and Archaea Are Fundamentally Different 287 Prokaryotes Differ in Shape and Structure 288 Prokaryotes Reproduce by Binary Fission 289 Prokaryotes Are Specialized for Specific Habitats 289 Prokaryotes Exhibit Diverse Metabolisms 290 Prokaryotes Perform Functions Important to Other Organisms 290 Some Bacteria Pose a Threat to Human Health 290 16.4 Protists 293 Most Protists Are Single Celled 293 The Chromists Include Photosynthetic and Nonphotosynthetic Organisms 293 The Alveolates Include Parasites, Predators, and Phytoplankton 294 Slime Molds Are Decomposers That Inhabit the Forest Floor 295 Various Protists Move by Means of Pseudopods 296 Green Algae Live Mostly in Ponds and Lakes 296 16.5 Fungi 297 Fungi Obtain Their Nutrients from Other Organisms 297 Most Fungi Can Reproduce Both Sexually and Asexually 298 Fungi Attack Plants That Are Important to People 298 Fungi Cause Human Diseases 298 Fungi Can Produce Toxins 299 Many Antibiotics Are Derived from Fungi 299 Fungi Make Important Contributions to Gastronomy 299 Fungi Play a Crucial Ecological Role 300 16.6 Plants 300 Bryophytes Lack Conducting Structures 300 The Vascular Plants Have Conducting Vessels That Also Provide Support 301 The Seedless Vascular Plants Include the Club Mosses, Horsetails, and Ferns 301 The Seed Plants Dominate the Land, Aided by Two Important Adaptations: Pollen and Seeds 301 Gymnosperms Are Nonflowering Seed Plants 302 Angiosperms Are Flowering Seed Plants 302 16.7 Animals 304 Most Animals Lack a Backbone 304 Sponges Have a Simple Body Plan 304 Cnidarians Are Well-Armed Predators 305 Annelids Are Composed of Identical Segments 306 Arthropods Are the Dominant Animals on Earth 306 Most Mollusks Have Shells 309 The Chordates Include Both Invertebrates and Vertebrates 310 Earth Watch: Frogs in Peril 313 An Unsolved Mystery Revisited 316 Links to Life 316 Chapter Review 316 UNIT FOUR PLANT ANATOMY AND PHYSIOLOGY 321 Chapter 17 Plant Form and Function 322 Sunscreen for Maple Trees? 323 17.1 How Are Plant Bodies Organized? 324 Flowering Plants Have a Root System and a Shoot System 324 Flowering Plants Can Be Divided into Two Groups 324 17.2 How Do Plants Grow? 324 During Growth, Meristem Cells Give Rise to Differentiated Cells 324 Different Processes Are Responsible for Growth in Length and Width 325 17.3 What Are the Tissues and Cell Types of Plants? 326 Dermal Tissue Covers the Plant Body 326 Ground Tissue Makes Up Most of the Young Plant Body 326 Vascular Tissue Consists of Xylem and Phloem 326 17.4 How Do Roots Grow and What Do They Do? 327 Roots Elongate by Primary Growth 328 The Epidermis of the Root Is Very Permeable to Water 328 The Cortex Controls the Absorption of Water and Nutrients 329 The Vascular Cylinder Contains Xylem and Phloem and Meristem for Branch Roots 329 17.5 How Do Stems Grow and What Do They Do? 329 The Epidermis of the Stem Retards Water Loss While Allowing Carbon Dioxide to Enter 329 The Cortex and Pith Support the Stem, Store Food, and Photosynthesize 330 Vascular Tissues in Stems Transport Water, Dissolved Nutrients, and Hormones 330 Branches Form from Lateral Buds Consisting of Meristem Cells 330 Secondary Growth Produces Thicker, Stronger Stems 330 17.6 What Is the Structure of Leaves and What Do They Do? 332 Leaves Have Two Major Parts 332 Specialized Leaves May Provide Support, Store Food, or Even Capture Insects 333 17.7 How Do Plants Acquire Nutrients? 333 Roots Take Up Minerals Dissolved in Water 333 Fungi and Bacteria Help Plants Acquire Nutrients 333 17.8 How Do Plants Acquire Water and Transport Water and Minerals? 334 Transpiration Provides the Force for Water Movement in Xylem 335 Water Enters Roots Mainly by Pressure Differences Created by Transpiration 335 Adjustable Stomata Control the Rate of Transpiration 335 Earth Watch: Plants Help Regulate the Distribution of Water 336 Sunscreen for Maple Trees? Revisited 336 Links to Life 337 Chapter Review 337 Chapter 18 The Plant Life Cycle 340 Fountain of Youth for Fruit 341 18.1 What Is the Life Cycle of Plants? 342 Two Types of Plant Bodies Alternate in the Sexual Life Cycle 342 Alternation of Generations Is Less Obvious in Flowering Plants 343 18.2 What Is the Structure of Flowers? 344 Flowers Evolved from Leaves 344 Flowers Incorporate Male and Female Reproductive Structures 345 18.3 What Are the Gametophytes of Flowering Plants? 345 The Pollen Grain Is the Male Gametophyte 345 The Embryo Sac Is the Female Gametophyte 345 18.4 How Does Pollination Lead to Fertilization? 346 18.5 How Do Seeds and Fruits Develop? 346 The Seed Develops from the Ovule and Embryo Sac 346 The Fruit Develops from the Ovary Wall 346 18.6 How Do Seeds Germinate and Grow? 347 Brotechnology Watch: Edible Vaccines 348 Seed Dormancy Helps Ensure Germination at an Appropriate Time 348 The Root Emerges First 348 The Shoot Tip Must Be Protected 349 Cotyledons Nourish the Sprouting Seed 349 Development Is Regulated throughout the Life Cycle 350 18.7 What Are Plant Hormones, and How Do They Act? 350 18.8 How Do Hormones Regulate the Plant Life Cycle? 350 Scientific Inquiry: How Were Plant Hormones Discovered? 351 Abscisic Acid Maintains Seed Dormancy 352 Gibberellin Stimulates Germination 352 Auxin Controls the Orientation of the Sprouting Seedling 352 Stem Branching Is Influenced by Auxin and Cytokinin 353 Gradients of Auxin and Cytokinin Create a Balance between the Root and Shoot Systems 353 Daylength Controls Flowering 353 Hormones Coordinate the Development of Seeds and Fruit 354 Senescence and Dormancy Prepare the Plant for Winter 355 Evolutionary Connections: Adaptations for Pollination and Seed Dispersal 355 Fountain of Youth for Fruit Revisited 358 Links to Life 358 Chapter Review 358 UNIT FIVE Animal Anatomy and Physiology 363 Chapter 19 Homeostasis and the Organization of the Animal Body 364 Surviving a Dive 365 1 How Do Animals Maintain Internal Constancy? 366 Negative Feedback Reverses the Effects of Changes 366 Positive Feedback Drives Events to a Conclusion 367 2 How Is the Animal Body Organized? 368 3 How Do Tissues Differ? 368 Epithelial Tissue Covers the Body and Lines Its Cavities 369 Some Epithelial Tissues Form Glands 369 Connective Tissues Have Diverse Structures and Functions 369 Muscle Tissue Has the Ability to Contract 371 Nerve Tissue Transmits Electrical Signals 371 4 How Are Tissues Combined into Organs? 372 Skin Is an Organ That Contains All Four Tissue Types 372 Organ Systems Consist of Two or More Interacting Organs 372 The Body's Organ Systems Act in Concert 374 Surviving a Dive Revisited 374 Links to Life 375 Chapter Review 375 Chapter 20 Circulation and Respiration 378 Organ Farmers 379 1 What Are the Major Features and Functions of Circulatory Systems? 380 Animals Have Two Types of Circulatory Systems 380 The Vertebrate Circulatory System Transports Many Substances 380 2 How Does the Vertebrate Heart Work? 381 The Vertebrate Heart Consists of Muscular Chambers 381 The Atria and Ventricles Contract in a Coordinated Cycle 382 Valves Prevent Blood from Moving in the Wrong Direction 383 Electrical Impulses Coordinate the Sequence of Contractions 383 The Heart's Contractions Result from Movement of Filaments in Muscle Cells 384 Injury and Disease Can Impair Heart Function 384 3 What Is Blood? 384 Plasma Is Primarily Water and Dissolved Substances 385 Red Blood Cells Carry Oxygen from the Lungs to the Tissues 385 White Blood Cells Help Defend the Body against Disease 386 Platelets Are Cell Fragments That Aid in Blood Clotting 386 Health Watch: Matters of the Heart 387 4 What Are the Types and Functions of Blood Vessels? 388 Arteries and Arterioles Carry Blood Away from the Heart 388 Capillaries Are Microscopic Vessels through Which Nutrients Are Exchanged 388 Venules and Veins Carry Blood Back to the Heart 389 5 How Does the Lymphatic System Work with the Circulatory System? 390 Lymphatic Vessels Resemble the Capillaries and Veins of the Circulatory System 390 The Lymphatic System Returns Fluids to the Blood 390 The Lymphatic System Transports Fats from the Small Intestine to the Blood 390 The Lymphatic System Helps Defend the Body against Disease 390 6 How Are Oxygen and Carbon Dioxide Exchanged in Animal Bodies? 391 Aquatic Animals May Have Gills 391 Terrestrial Animals Have Internal Respiratory Structures 392 7 How Does the Human Respiratory System Work? 392 The Conducting Portion Carries Air to the Lungs 392 Gas Exchange Occurs in the Alveoli 393 Health Watch: Smoking; A Life and Breath Decision 394 The Lungs Are Protected by an Airtight Cavity 395 Air Is Inhaled Actively and Exhaled Passively 395 Breathing Rate Is Controlled by the Respiratory Center of the Brain 396 Organ Farmers Revisited 396 Links to Life 397 Chapter Review 397 Chapter 21 Nutrition, Digestion, and Excretion 400 Is There a Magic Bullet for Obesity? 401 21.1 What Nutrients Do Animals Need? 402 The Primary Sources of Energy Are Lipids and Carbohydrates 402 Lipids Include Fats, Phospholipids, and Cholesterol 402 Carbohydrates Are a Source of Quick Energy 403 Proteins Provide Amino Acid Building Blocks 404 Minerals Are Elements and Small Inorganic Molecules 404 Vitamins Play Many Roles in Metabolism 405 Nutritional Guidelines Help People Obtain a Balanced Diet 406 Are You Too Heavy? 406 21.2 How Is Digestion Accomplished? 407 Health Watch: Eating Disorders; Betrayal of the Body 408 Digestion Includes Several Processes 408 A Sac with One Opening Forms the Simplest Digestive System 409 Digestion in a Tube Allows More Frequent Meals 409 21.3 How Do Humans Digest Food? 410 The Mechanical and Chemical Breakdown Begins in the Mouth 411 The Pharynx Connects the Mouth to the Rest of the Digestive System 411 The Esophagus Conducts Food to the Stomach 411 The Stomach Stores and Further Breaks Down Food 412 Most Digestion Occurs in the Small Intestine 412 Most Absorption Occurs in the Small Intestine 413 Water Is Absorbed and Feces Are Formed in the Large Intestine 414 Digestion Is Controlled by the Nervous System and Hormones 414 21.4 What Are the Functions of Urinary Systems? 415 Flame Cells Filter Fluids in Flatworms 415 Health Watch: When the Kidneys Collapse 416 Nephridia Filter Fluid in Earthworms 416 21.5 How Does the Human Urinary System Work? 417 The Urinary System Produces, Transports, and Excretes Urine 417 The Kidneys Are Important Organs of Homeostasis 417 Urine Forms in the Kidneys 418 Kidneys Contain Filters Called Nephrons 418 Urine Becomes Concentrated in the Collecting Duct 419 Negative Feedback Regulates the Water Content of the Blood 419 Is There a Magic Bullet for Obesity? Revisited 420 Links to Life 420 Chapter Review 420 Chapter 22 Defenses Against Disease: The Immune Response 424 Will a Vaccine Make the Woods Safer? 425 22.1 How Does the Body Defend against Invasion? 426 The Skin and Mucous Membranes Are Nonspecific External Barriers to Invasion 426 Nonspecific Internal Defenses Combat Invaders 427 22.2 What Are the "Soldiers" of the Immune Response? 429 White Blood Cells Are Key Components of the Immune System 430 Immune Cells Originate in the Bone Marrow 430 22.3 How Does the Immune System Recognize Invaders? 430 Invaders' Cell Surface Molecules Are Recognized 430 Antibodies Recognize and Bind to Antigens 430 T-Cell Receptors Also Recognize and Bind Antigens 431 The Immune System Can Recognize Millions of Different Molecules 431 The Immune System Distinguishes "Self" from "Non-Self" 432 22.4 How Does the Immune System Launch an Attack? 432 Humoral Immunity Is Produced by Antibodies Dissolved in Blood 433 Cell-Mediated Immunity Is Produced by T Cells 434 22.5 How Does the Immune System Remember Its Past Victories? 434 22.6 How Does Medical Care Assist the Immune Response? 434 Antibiotics Slow Down Microbial Reproduction 435 Health Watch: Can We Beat the Flu Bug? 436 Vaccinations Stimulate the Development of Memory Cells 437 22.7 What Happens When the Immune System Malfunctions? 437 Scientific Inquiry: How Vaccines Were Discovered 438 Allergies Are Misdirected Immune Responses 438 An Autoimmune Disease Is an Immune Response against the Body's Own Cells 439 An Immune Deficiency Disease Eliminates the Immune Response 439 Cancer Can Evade or Overwhelm the Immune Response 441 Will a Vaccine Make the Woods Safer? Revisited 442 Links to Life 443 Chapter Review 443 Chapter 23 Chemical Control of the Animal Body: The Endocrine System 446 Are Some Pollutants "Gender Benders"? 447 23.1 What Are the Characteristics of Animal Hormones? 448 Many Different Molecules Serve As Hormones 448 Hormones Bind to Specific Receptors on Target Cells 448 Hormone Release Is Regulated by Feedback 450 23.2 What Are the Structures of the Mammalian Endocrine System? 452 Some Glands Are Not Part of the Endocrine System 452 Hormone-Producing Glands Are Enmeshed in Blood Vessels 452 23.3 What Are the Functions of the Hypothalamus and Pituitary Gland? 452 Hormones from the Hypothalamus Control the Anterior Pituitary 453 The Anterior Pituitary Produces and Releases Several Hormones 454 The Posterior Pituitary Releases Hormones from the Hypothalamus 455 23.4 What Does the Thyroid Gland Do? 456 Thyroxine Influences Metabolism 456 Thyroxine Release Is Controlled by the Hypothalamus 456 23.5 What Does the Pancreas Do? 456 Pancreatic Hormones Control Glucose Levels in the Blood 457 Diabetes Results from Malfunctions of the Insulin Control System 457 23.6 What Are the Endocrine Functions of Sex Organs? 458 Sex Hormone Levels Increase During Puberty 458 23.7 What Do the Adrenal Glands Do? 458 The Hormones of the Adrenal Medulla Prepare the Body to Flee or Fight 459 The Hormones of the Adrenal Cortex Raise Blood Glucose in Response to Stress 459 23.8 What Are Some Other Sources of Hormones? 459 Health Watch: Losing on Artficial Hormones 460 Are Some Polllutants "Gender Benders"? Revisited 461 Links to Life 461 Chapter Review 462 Chapter 24 The Nervous System and the Senses 464 Can You Live with a Hole in Your Head? 465 24.1 How Do Nerve Cells Work? 466 Dendrites Respond to Stimuli 466 The Cell Body Receives Signals from Dendrites 466 Axons Are the Neuron's Distribution Lines 466 Signals Are Transmitted at Synaptic Terminals 467 24.2 How Do Nerve Cells Produce and Transmit Signals? 467 The Potential inside a Neuron Changes During an Action Potential 467 Neurons Communicate at Synapses 467 Excitatory and Inhibitory Potentials Are Produced at Synapses 468 Excitatory and Inhibitory Potentials Are Integrated in the Cell Body 468 The Nervous System Uses Many Neurotransmitters 468 24.3 How Do Nervous Systems Process Information? 468 The Type of Stimulus Is Distinguished by Wiring Patterns in the Brain 469 The Intensity of a Stimulus Is Revealed by the Frequency of Signals 469 Health Watch: Drugs, Diseases, and Neurotransmitters 470 Information from Many Sources Converges in Certain Neurons 471 Complex Responses Require Divergence of Signals 471 24.4 How Do Nervous Systems Direct Behavior? 471 24.5 How Is the Human Nervous System Organized? 471 The Peripheral Nervous System Links the Central Nervous System to the Body 472 The Central Nervous System Consists of the Spinal Cord and Brain 474 The Spinal Cord Is a Cable of Axons Protected by the Backbone 474 The Brain Consists of Many Parts 475 Health Watch: Healing the Spinal Cord 476 The Hindbrain Controls Breathing, Sleep, and Movement 476 The Midbrain Filters Input 477 The Forebrain Gives Us Our Emotions, Thoughts, and Perceptions 477 24.6 How Does the Brain Produce the Mind? 479 The "Left Brain" and "Right Brain" Have Different Specialties 479 Learning and Memory Are Areas of Active Investigation 480 Insights on How the Brain Creates the Mind Come from Diverse Sources 480 24.7 How Do Sensory Receptors Work? 481 24.8 How Is Sound Sensed? 482 The Ear Captures and Transmits Sound 482 Sound Is Converted into Electrical Signals in the Cochlea 483 24.9 How Is Light Sensed? 483 The Eye Collects and Focuses Light 484 The Adjustable Lens Can Focus on Distant and Nearby Objects 484 Light Striking the Retina Is Captured by Photoreceptors 485 Rods and Cones Differ in Distribution and Light Sensitivity 485 24.10 How Are Chemicals Sensed? 485 The Ability to smell Arises from Olfactory Receptors 486 Taste Receptors Are Clustered on the Tongue 486 Pain Is a Specialized Chemical Sense 486 Evolutionary Connections: Uncommon Senses 487 Can You Live with a Hole in Your Head? Revisited 488 Links to Life 488 Chapter Review 489 Chapter 25 Animal Reproduction and Development 000 Making Far-Reaching Choices 000 25.1 How Do Animals Reproduce? 000 In Asexual Reproduction, There Is No Fusion of Sperm and Egg 000 Sexual Reproduction Requires the Union of Sperm and Egg 000 Gametes Are Brought Together for Fertilization in Various Ways 000 25.2 How Does the Human Reproductive System Work? 000 The Male Reproductive System Includes the Testes and Other Structures 000 The Female Reproductive System Includes the Ovaries and Other Structures 000 Copulation Allows Internal Fertilization 000 25.3 How Does Animal Development Proceed? 000 The Fertilized Egg Develops into a Hollow Ball of Cells 000 Next, Three Tissue Layers Form 000 Eventually, Adult Structures Form 000 25.4 How Do Humans Develop? 000 Differentiation and Growth Are Rapid in the First Two Months 000 Growth and Development Continue During the Last Seven Months 000 The Placenta Exchanges Materials between Mother and Fetus 000 Development Culminates in Labor and Delivery 000 Pregnancy Hormones Stimulate Milk Secretion 000 25.5 How Can People Limit Fertility? 000 Sterilization Provides Permanent Contraception 000 There Are Three General Approaches to Temporary Contraception 000 Making Far-Reaching Choices Revisited 000 Health Watch: Sexually Transmitted Diseases 000 Scientific Inquiry: High-Tech Reproduction 000 Biotechnology Watch: The Promise of Stem Cells 000 Links to Life 000 Chapter Review 000 Chapter 26 Animal Behavior 000 Sex and Symmetry 000 26.1 How Do Innate and Learned Behaviors Differ? 000 Innate Behaviors Can Be Performed without Prior Experience 000 Learned Behaviors Are Modified by Experience 000 There Is No Sharp Distinction between Innate and Learned Behaviors 000 26.2 How Do Animals Communicate? 000 Visual Communication Is Most Effective over Short Distances 000 Communication by Sound Is Effective over Longer Distances 000 Chemical Messages Persist Longer But Are Hard to Vary 000 Communication by Touch Helps Establish Social Bonds 000 26.3 How Do Animals Compete for Resources? 000 Aggressive Behavior Helps Secure Resources 000 Dominance Hierarchies Help Manage Aggressive Interactions 000 Animals May Defend Territories That Contain Resources 000 26.4 How Do Animals Find Mates? 000 Signals Encode Sex, Species, and Individual Quality 000 26.5 What Kinds of Societies Do Animals Form? 000 Group Living Has Advantages and Disadvantages 000 Sociality Varies among Species 000 Forming Groups with Relatives Fosters the Evolution of Altruism 000 Honeybees Live Together in Rigidly Structured Societies 000 Naked Mole Rats Form a Complex Vertebrate Society 000 26.6 Can Biology Explain Human Behavior? 000 The Behavior of Newborn Infants Has a Large Innate Component 000 Young Humans Acquire Language Easily 000 Behaviors Shared by Diverse Cultures May Be Innate 000 Humans May Respond to Pheromones 000 Studies of Twins Reveal Genetic Components of Behavior 000 Biological Investigation of Human Behavior Is Controversial 000 Evolutionary Connections: Why Do Animals Play? 000 Sex and Symmetry Revisited 000 Links to Life 000 Chapter Review 000 UNIT SIX Ecology 000 Chapter 27 Population Growth 000 The Mystery of Easter Island 000 27.1 How Are Populations Distributed in Space and Time? 000 Individuals in Many Populations Clump Together in Groups 000 Some Individuals Disperse Themselves Evenly 000 In a Few Populations, Individuals Are Distributed at Random 000 27.2 How Do Populations Grow? 000 Births, Deaths, and Migration Determine Population Growth 000 A Population's Growth Rate Depends on Patterns of Reproduction 000 27.3 How Is Population Growth Regulated? 000 Rapid Growth Cannot Continue Indefinitely 000 Environmental Resistance Limits Population Growth 000 27.4 How Is the Human Population Changing? 000 Technological Advances Have Increased Earth's Carrying Capacity for Humans 000 Population Growth Continues Today But Is Unevenly Distributed 000 The Age Structure of a Population Predicts Its Future Growth 000 The U.S. Population Is Growing Rapidly 000 Scientific Inquiry: Cycles in Predator and Prey Populations 000 Earth Watch: Have We Exceeded Earth's Carrying Capacity? 000 The Mystery of Easter Island Revisited 000 Links to Life 000 Chapter Review 000 Chapter 28 Community Interactions 000 The Case of the Vanishing Sea Otters 000 28.1 Why Are Interactions in Ecological Communities Important? 000 Community Interactions Help Limit Population Size 000 Community Interactions Influence Evolutionary Change 000 28.2 What Are the Effects of Competition among Species? 000 Each Species Has a Unique Place in Its Ecosystem 000 The Ecological Niches of Coexisting Species Never Overlap Completely 000 Competitive Exclusion Helps Determine How Populations Are Distributed 000 Species Evolve to Reduce Niche Overlap 000 28.3 What Are the Effects of Predator/Prey Interactions? 000 Predator and Prey Coevolve 000 Camouflage Conceals Both Predators and Their Prey 000 Bright Colors Often Warn of Danger 000 Some Organisms Gain Protection through Mimicry 000 Some Animal Predators and Prey Engage in Chemical Warfare 000 Plants Have Defenses against Herbivores 000 Herbivores Have Adaptations for Overcoming Plant Defenses 000 28.4 What Is Symbiosis? 000 Parasites Harm, But Do Not Immediately Kill, the Host 000 In Mutualistic Interactions, Both Species Benefit 000 28.5 What Are Keystone Species? 000 28.6 How Does a Community Change over Time? 000 There Are Two Main Types of Succession 000 Ponds and Lakes Eventually Fill In 000 Succession Culminates in the Climax Community 000 Some Ecosystems Are Maintained in a Subclimax State 000 Evolutionary Connections: Is Camouflage Splitting a Species? 000 Earth Watch: Exotic Invaders 000 The Case of the Vanishing Sea Otters Revisited 000 Links to Life 000 Chapter Review 000 Chapter 29 How Do Ecosystems Work? 000 A World in a Bubble 000 29.1 How Do Ecosystems Obtain Energy and Nutrients? 000 29.2 How Does Energy Flow through Ecosystems? 000 Energy Enters Ecosystems through Photosynthesis 000 Energy Captured by Producers Is Available to the Ecosystem 000 Energy Passes from One Trophic Level to Another 000 Feeding Relationships within Ecosystems Form Chains and Webs 000 Detritus Feeders and Decomposers Release Nutrients for Reuse 000 Energy Transfer through Trophic Levels Is Inefficient 000 Energy Pyramids Illustrate Energy Transfer between Trophic Levels 000 29.3 How Do Nutrients Move within and among Ecosystems? 000 Carbon Cycles through the Atmosphere, Oceans, and Communities 000 The Major Reservoir for Nitrogen Is the Atmosphere 000 The Major Reservoir for Phosphorus Is Rock 000 Water Remains Unchanged During the Water Cycle 000 29.4 What Is Causing Acid Rain and Global Warming? 000 Overloading the Nitrogen and Sulfur Cycles Causes Acid Rain 000 Disruption of the Carbon Cycle Contributes to Global Warming 000 Earth Watch: Food Chains Magnify Toxic Substances 000 Biotechnology Watch: Are Genetically Modified Crops Safe for the Environment? 000 A World in a Bubble Revisited 000 Links to Life 000 Chapter Review 000 Chapter 30 Earth's Diverse Ecosystems 000 Can Coffee Save Songbirds? 000 30.1 What Factors Influence Earth's Climate? 000 Both Climate and Weather Are Driven by the Sun 000 Sunlight Strikes Earth at Various Angles 000 Air Currents Produce Regional Climates 000 Ocean Currents Moderate Nearshore Climates 000 Continents and Mountains Complicate Weather and Climate 000 30.2 What Conditions Does Life Require? 000 30.3 How Is Life on Land Distributed? 000 Terrestrial Biomes Have Characteristic Plant Communities 000 Rainfall and Temperature Determine the Vegetation a Biome Can Support 000 30.4 How Is Life in Water Distributed? 000 Freshwater Lakes Have Distinct Regions of Life 000 Marine Ecosystems Cover Much of Earth 000 Earth Watch: The Ozone Hole; A Puncture in Our Protective Shield 000 Earth Watch: Humans and Ecosystems 000 Can Coffee Save Songbirds? Revisited 000 Links to Life 000 Chapter Review 000 Appendix I: Metric System Conversion 000 Appendix II: Classification of Major Groups of Organisms 000 Appendix III: Periodic Table of Elements 000 Glossary G-1 Selected Answers A-1 Photo Credits P-1 Index I-1 Preface Will scientists clone a person in the foreseeable future? Are genetically engineered crops safe? Are people causing climate change? Is AIDS still spreading? Will physicians soon be transplanting pig hearts into people? Why are antibiotic medicines becoming less effective? Many of today's most important and controversial social, medical, environmental, and ethical issues are related to biology. The need for citizens to understand the basic concepts of biology has never been more urgent. Many of the students who will use this text are enrolled in a course that will provide their final exposure to biology before they go out into the world. We hope that they will emerge from the course prepared to ask intelligent questions, make informed choices, and scrutinize science articles in the popular press with an educated and critical eye. We also hope that students will better understand and appreciate their own bodies, the other organisms with which we share Earth, the evolutionary forces that molded all life-forms, and how complex interactions within ecosystems sustain us and all other life on Earth. Perhaps most of all, we hope that students will develop a fascination with life that will inspire them to keep learning. To help instructors achieve these teaching goals, we offer this revision of Life on Earth. Now in its fourth edition, Life on Earth Effectively Manages a Wealth of Scientific Information and Motivates Students The fourth edition of Life on Earth; which is more than a textbook, but rather a complete package of teaching aids for the instructor and learning aids for students; has been revised with three specific goals: - To help instructors manage the presentation of biological information with the goal of producing scientifically literate students - To help students build familiarity with the process of science through an engaging storyline - To help students relate this information to their own lives so as to understand its importance and relevance Life on Earth . . . Is Organized Clearly and Uniformly Throughout each chapter, students will find aids that help them navigate through the information. - "At a Glance" at the start of each chapter brings together the chapter's major subheadings and now includes the titles of Essays as well. Instructors can easily assign; and students can easily locate; key topics within the chapter. - Major sections are introduced as questions to which the student will find answers in the section, while minor subheadings are presented as summary statements that reflect content. A crucial outgrowth of this organizational scheme is that it imparts an understanding of biology as a hierarchy of interrelated concepts, rather than a set of isolated, independent subjects. - The "Summary of Key Concepts" pulls together important concepts using the major subheadings as an organizing feature. Both "At a Glance" and the "Summary of Key Concepts" use the heading- based numbering system featured within the chapters themselves, allowing instructors and students to move efficiently among the different components within a chapter. - Information is integrated and easily managed within the total package. Media Activity tabs within each chapter direct the student to OneKey, which contains relevant activities, animations, and practice tests; the Media Activity numbers in the book correspond with OneKey for easy navigation. Detailed descriptions of each Media Activity are found at the end of each chapter. . . . Contains Revitalized Illustrations for Greater Clarity, Consistency, and Reader Interest Benefiting from the advice of reviewers, a talented biological illustrator, and careful scrutiny by the authors and development editor, we have extensively revised the illustration program. For the fourth edition, we have: - Expanded the consistent use of color. We have been vigilant in tracking the use of color to provide consistency in illustrating specific atoms, structures, or processes. We have also made the colors more vibrant to better distinguish individual parts of a figure, to help engage the readers' interest, and to focus attention on the most important aspects of the illustration. - Improved overall quality. We have redrawn the more diagrammatic figures for greater interest and accuracy. - Enhanced label clarity. We have revised the size, placement, and font of figure labels for more consistency and readability. - Organized content more efficiently. We have modified the placement of parts of multipart figures for easier navigation through the figure. - Explained figure content more clearly. Through the judicious use of "talking boxes," we have placed more explanatory statements within figures for greater clarity. - Modified figure captions to enhance function. Our figure titles summarize the content; we have made the captions more concise, and have added thought questions to several captions within each chapter. _ Actively Engages and Motivates Students Scientific literacy cannot be imposed on students; they must actively participate in acquiring both the necessary information and skills. Thus, it is crucial for students to recognize that biology is about their personal lives as well as the life all around them. To help engage and motivate students, this new edition incorporates the following: _ Openers/Closers. Each chapter opens with a strikingly illustrated brief essay. The opener essays are based on recent news items, on situations in which students might find themselves, or on particularly fascinating biological topics. For example, students will investigate blood doping by elite athletes (p. 00); contemplate the use of DNA to solve historical mysteries (p. 00) and crimes (p. 00); see cloned, genetically engineered pigs that are being raised as potential organ donors for humans (p. 000); and follow along as a scientist estimates the number of species on Earth (p. 000). Each opener is revisited at the end of the chapter, allowing students to explore the topic a bit further in light of what they have learned and, often, to find answers to questions raised in the initial piece. The "revisited" essays conclude with a new "Consider This" segment that poses an open- ended question to encourage deeper thinking about the topic. _ Links to Life. A new feature in the fourth edition, Links to Life ends each chapter on a relevant note. These short, informally written segments relate to subjects that are both very familiar to the student and relevant to the chapter. _ Caption Queries: New in this edition, selected figure captions in each chapter include questions designed to encourage readers to review and extend their new knowledge of the pictured structure or process. _ Bioethics: Another new feature in the fourth edition, many topics explored in the text have ethical implications. Many of these topics are now identified by an icon that alerts students and teachers to the possibility of further discussion and exploration. _ Essays. We retain our full suite of essays, including "Earth Watch," environmental essays that explore issues such as the loss of biodiversity, the growing ozone hole, and invasions of exotic species, and our medically related "Health Watch" essays, which investigate topics such as sexually transmitted diseases, the dangers of artificial steroids, and how smoking damages the lungs. New in this edition, "Biotechnology Watch" essays examine the impact of new technologies such as cloning, in vitro fertilization, and genetic modification of organisms. É Emphasizes Scientific Reasoning In order to made sound decisions at the voting booth or to evaluate assertions made by the media, students need to think critically. To develop scientific reasoning skills, we have added the following: _ Openers/Closers. In addition to the engaging, relevant biological storyline, the opener essays are designed to build students' familiarity with the process of science and to demonstrate how scientists use the process to reach conclusions. The opening and the closing essays incorporate many examples of questions posed, hypotheses stated, predictions made, and experimental tests performed. Our aim is to show by example how scientists gather objective evidence about interesting questions relevant to students' lives. We hope that student readers of Life on Earth will begin to think like scientists. Nothing would please us more than a student who, upon hearing an assertion on television or reading a claim on the internet, instinctively asks, "What is the evidence and how was it gathered?" _ Is This Science. We have added new "Is This Science?" questions to the "Applying the Concepts" critical-thinking questions at the end of each chapter. The new questions are designed to help students practice their scientific reasoning and critical thinking skills. _ Provides Print and Media Resources That Aid User Exploration _ OneKey (www.prenhall.com/audesirk4): OneKey provides instructors and students with a single internet location for a superb collection of teaching and learning resources. OneKey for Life on Earth 4e supplies anywhere, anytime access to conveniently organized course materials. OneKey also includes everything instructors need to plan and administer courses. All instructor resources are consolidated in one location for maximum effectiveness and efficiency. _ Instructor Resource Center on CD: This single CD contains all digital resources, easily searchable with the included search tool. The material can also be browsed by chapter or resource type. The included Resource Manager makes it easy to post images, questions, animations, and more to your course web site. _ Instructor Resource Guide: This booklet is the print companion to the Instructor's Resource Center on CD. It includes the Resource Directory, Chapter At a Glance, Lecture Activities, Lecture Resources, Key Terms, end-of-chapter questions and answers, and figure caption questions and answers. _ Instructor Toolbox: The Toolbox contains all print supplements, organized by chapter. Included are all of the materials in the Instructor Resource Guide, plus overhead transparences. _ Accelerator CD: Each copy of this text includes an Accelerator CD. The CD works with One Key to provide a faster internet experience. The Accelerator CD stores some OneKey content, so that even dial-up connections can provide snappy performance. _ Student Study Companion: The printed Companion provides OneKey questions and review materia to students without access to the internet. Acknowledgments Life on Earth is truly a group effort. To meet the dauntingly complex challenge of putting together a text and supplement package of this magnitude, Prentice Hall has assembled an experienced and skilled development team. The text benefited considerably from the thoughtful suggestions of Developmental Editor Anne Reid. She helped us keep the text clear, consistent, and student-friendly. Tim Flem, our Production Editor, coordinated the efforts of the photo researcher, copy editor, art studio, and authors. He skillfully brought the art, photos, and manuscript together into a seamless whole while dealing good-naturedly with last-minute improvements. Formatting this book is not an easy endeavor, but Tim applied his expertise with great attention to detail. Photo Researcher Yvonne Gerin tracked down excellent photos. Margo Quinto tackled the job of copyediting with exceptional skill. We also wish to thank Art Director John Christiana for guiding the text and cover design with flair and talent, and Art Editor Sean Hogan for coordinating such an immense art program. Travis Moses-Westphal, our Media Editor, deftly carried the vision for the media program and oversaw the seamless integration of the text, media, and print supplements. Assistant Editors Colleen Lee and Andrew Sobel provided invaluable support and assistance. Editorial Assistant Marilyn Coco cheerfully and efficiently trafficked the manuscript. Andrew Gilfillan, our Marketing Manager, oversees a large and dedicated sales force with energy, talent, and enthusiasm. Andrew provides inspired marketing concepts, shares success stories, and makes sure that user's comments always get through to the authors. We thank Paul Corey, now president of the Engineering, Science, and Mathematics Division of Prentice Hall, for his confidence and support through this and the past three editions. Finally, but most importantly, our editors: Editor in Chief John Challice has supported us from the very beginning. Executive Editor Teresa Ryu Chung has assumed leadership of the team with talent and zeal, combined with a clear sense of where the project should be going and how to get it there without killing the authors. Her total commitment to the project, her organizational ability, and her sensitivity to all the people involved have been crucial to its success. So here we acknowledge, with deep appreciation, our "coach" and all our teammates! Terry and Gerry Audesirk Bruce E. Byers
Library of Congress Subject Headings for this publication: