Campbell Biology, 12th Edition
By Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky and Rebecca B. Orr
Detailed Contents:
1 Evolution, the Themes of Biology,
and Scientific Inquiry 2
CONCEPT 1.1 The study of life reveals unifying themes 3
Theme: New Properties Emerge at Successive Levels of Biological Organization 4
Theme: Life’s Processes Involve the Expression and Transmission of Genetic Information 6
Theme: Life Requires the Transfer and Transformation of Energy and Matter 9
Theme: From Molecules to Ecosystems, Interactions Are Important in Biological Systems 9
CONCEPT 1.2 The Core Theme: Evolution accounts for the unity and diversity of life 11
Classifying the Diversity of Life 12
Charles Darwin and the Theory of Natural Selection 14
The Tree of Life 15
CONCEPT 1.3 In studying nature, scientists form and test hypotheses 16
Exploration and Observation 17
Gathering and Analyzing Data 17
Forming and Testing Hypotheses 17
The Flexibility of the Scientific Process 18
A Case Study in Scientific Inquiry: Investigating Coat Coloration in Mouse Populations 20
Variables and Controls in Experiments 20
Theories in Science 21
CONCEPT 1.4 Science benefits from a cooperative approach and diverse viewpoints 22
Building on the Work of Others 22
Science, Technology, and Society 23
The Value of Diverse Viewpoints in Science 24
Unit 1 The Chemistry of Life 27
2 The Chemical Context of Life 28
CONCEPT 2.1 Matter consists of chemical elements in pure form and in combinations called
compounds 29
Elements and Compounds 29
The Elements of Life 29
Case Study: Evolution of Tolerance to Toxic Elements 30
CONCEPT 2.2 An element’s properties depend on the structure of its atoms 30
Subatomic Particles 30
Atomic Number and Atomic Mass 31
Isotopes 31
The Energy Levels of Electrons 32
Electron Distribution and Chemical Properties 34
Electron Orbitals 35
CONCEPT 2.3 The formation and function of molecules and ionic compounds depend on chemical
bonding between atoms 36
Covalent Bonds 36
Ionic Bonds 37
Weak Chemical Interactions 38
Molecular Shape and Function 39
CONCEPT 2.4 Chemical reactions make and break chemical bonds 40
3 Water and Life 44
CONCEPT 3.1 Polar covalent bonds in water molecules result in hydrogen bonding 45
CONCEPT 3.2 Four emergent properties of water contribute to Earth’s suitability for life 45
Cohesion of Water Molecules 45
Moderation of Temperature by Water 46
Floating of Ice on Liquid Water 48
Water: The Solvent of Life 49
Possible Evolution of Life on Other Planets 50
CONCEPT 3.3 Acidic and basic conditions affect living organisms 51
Acids and Bases 51
The pH Scale 51
Buffers 52
Acidification: A Threat to Our Oceans 53
4 Carbon and the Molecular
Diversity of Life 56
CONCEPT 4.1 Organic chemistry is key to the origin of life 57
CONCEPT 4.2 Carbon atoms can form diverse molecules by bonding to four other atoms 58
The Formation of Bonds with Carbon 58
Molecular Diversity Arising from Variation in Carbon Skeletons 60
CONCEPT 4.3 A few chemical groups are key to molecular function 62
The Chemical Groups Most Important in the Processes of Life 62
ATP: An Important Source of Energy for Cellular Processes 64
The Chemical Elements of Life: A Review 64
5 The Structure and Function of
Large Biological Molecules 66
CONCEPT 5.1 Macromolecules are polymers, built from monomers 67
The Synthesis and Breakdown of Polymers 67
The Diversity of Polymers 67
CONCEPT 5.2 Carbohydrates serve as fuel and building material 68
Sugars 68
Polysaccharides 70
CONCEPT 5.3 Lipids are a diverse group of hydrophobic molecules 72
Fats 72
Phospholipids 74
Steroids 75
CONCEPT 5.4 Proteins include a diversity of structures, resulting in a wide range of functions 75
Amino Acids (Monomers) 75
Polypeptides (Amino Acid Polymers) 78
Protein Structure and Function 78
CONCEPT 5.5 Nucleic acids store, transmit, and help express hereditary information 84
The Roles of Nucleic Acids 84
The Components of Nucleic Acids 84
Nucleotide Polymers 85
The Structures of DNA and RNA Molecules 86
CONCEPT 5.6 Genomics and proteomics have transformed biological inquiry and applications 86
DNA and Proteins as Tape Measures of Evolution 87
Unit 2 The Cell 92
6 A Tour of the Cell 93
CONCEPT 6.1 Biologists use microscopes and biochemistry to study cells 94 Microscopy 94
Cell Fractionation 96
CONCEPT 6.2 Eukaryotic cells have internal membranes that compartmentalize their functions 97
Comparing Prokaryotic and Eukaryotic Cells 97
A Panoramic View of the Eukaryotic Cell 99
CONCEPT 6.3 The eukaryotic cell’s genetic instructions are housed in the nucleus and carried out by the ribosomes 102
The Nucleus: Information Central 102
Ribosomes: Protein Factories 102
CONCEPT 6.4 The endomembrane system regulates protein traffic and performs metabolic functions
104
The Endoplasmic Reticulum: Biosynthetic Factory 104
The Golgi Apparatus: Shipping and Receiving Center 105
Lysosomes: Digestive Compartments 107
Vacuoles: Diverse Maintenance Compartments 108
The Endomembrane System: A Review 108
CONCEPT 6.5 Mitochondria and chloroplasts change energy from one form to another 109
The Evolutionary Origins of Mitochondria and Chloroplasts 109
Mitochondria: Chemical Energy Conversion 110
Chloroplasts: Capture of Light Energy 110
Peroxisomes: Oxidation 112
CONCEPT 6.6 The cytoskeleton is a network of fibers that
organizes structures and activities in the cell 112
Roles of the Cytoskeleton: Support and Motility 112
Components of the Cytoskeleton 113
CONCEPT 6.7 Extracellular components and connections between cells help coordinate cellular
activities 118
Cell Walls of Plants 118
The Extracellular Matrix (ECM) of Animal Cells 118
Cell Junctions 119
CONCEPT 6.8 A cell is greater than the sum of its parts 121
7 Membrane Structure
and Function 126
CONCEPT 7.1 Cellular membranes are fluid mosaics of lipids and proteins 127
The Fluidity of Membranes 128
Evolution of Differences in Membrane Lipid Composition 129
Membrane Proteins and Their Functions 129
The Role of Membrane Carbohydrates in Cell-Cell Recognition 130
Synthesis and Sidedness of Membranes 131
CONCEPT 7.2 Membrane structure results in selective permeability 131
The Permeability of the Lipid Bilayer 132
Transport Proteins 132
CONCEPT 7.3 Passive transport is diffusion of a substance across a membrane with no energy
investment 132
Effects of Osmosis on Water Balance 133
Facilitated Diffusion: Passive Transport Aided by Proteins 135
CONCEPT 7.4 Active transport uses energy to move solutes against their gradients 136
The Need for Energy in Active Transport 136
How Ion Pumps Maintain Membrane Potential 137
Cotransport: Coupled Transport by a Membrane Protein 138
CONCEPT 7.5 Bulk transport across the plasma membrane occurs by exocytosis and endocytosis 139
Exocytosis 139
Endocytosis 139
8 An Introduction to
Metabolism 143
CONCEPT 8.1 An organism’s metabolism transforms matter and energy 144
Metabolic Pathways 144
Forms of Energy 144
The Laws of Energy Transformation 145
CONCEPT 8.2 The free-energy change of a reaction tells us whether or not the reaction occurs
spontaneously 147
Free-Energy Change, ΔG 147
Free Energy, Stability, and Equilibrium 147
Free Energy and Metabolism 148
CONCEPT 8.3 ATP powers cellular work by coupling exergonic reactions to endergonic reactions 150
The Structure and Hydrolysis of ATP 150
How ATP Provides Energy That Performs Work 151
The Regeneration of ATP 153
CONCEPT 8.4 Enzymes speed up metabolic reactions by lowering energy barriers 153
The Activation Energy Barrier 153
How Enzymes Speed Up Reactions 154
Substrate Specificity of Enzymes 155
Catalysis in the Enzyme’s Active Site 156
Effects of Local Conditions on Enzyme Activity 157
The Evolution of Enzymes 159
CONCEPT 8.5 Regulation of enzyme activity helps control metabolism 159
Allosteric Regulation of Enzymes 160
Localization of Enzymes Within the Cell 161
9 Cellular Respiration and Fermentation 164
CONCEPT 9.1 Catabolic pathways yield energy by oxidizing organic fuels 165
Catabolic Pathways and Production of ATP 165
Redox Reactions: Oxidation and Reduction 165
The Stages of Cellular Respiration: A Preview 168
CONCEPT 9.2 Glycolysis harvests chemical energy by oxidizing glucose to pyruvate 170
CONCEPT 9.3 After pyruvate is oxidized, the citric acid cycle completes the energy-yielding oxidation
of organic molecules 171
Oxidation of Pyruvate to Acetyl CoA 171
The Citric Acid Cycle 172
CONCEPT 9.4 During oxidative phosphorylation,
chemiosmosis couples electron transport to ATP synthesis 174
The Pathway of Electron Transport 174
Chemiosmosis: The Energy-Coupling Mechanism 175
An Accounting of ATP Production by Cellular Respiration 177
CONCEPT 9.5 Fermentation and anaerobic respiration enable cells to produce ATP without the use of oxygen 179
Types of Fermentation 180
Comparing Fermentation with Anaerobic and Aerobic Respiration 181
The Evolutionary Significance of Glycolysis 182
CONCEPT 9.6 Glycolysis and the citric acid cycle connect to many other metabolic pathways 182
The Versatility of Catabolism 182
Biosynthesis (Anabolic Pathways) 183
Regulation of Cellular Respiration via Feedback Mechanisms 183
10 Photosynthesis 187
CONCEPT 10.1 Photosynthesis feeds the biosphere 188
CONCEPT 10.2 Photosynthesis converts light energy to the chemical energy of food 189
Chloroplasts: The Sites of Photosynthesis in Plants 189
Tracking Atoms Through Photosynthesis 189
The Two Stages of Photosynthesis: A Preview 191
CONCEPT 10.3 The light reactions convert solar energy to the chemical energy of ATP and NADPH 192
The Nature of Sunlight 192
Photosynthetic Pigments: The Light Receptors 192
Excitation of Chlorophyll by Light 195
A Photosystem: A Reaction-Center Complex Associated with
Light-Harvesting Complexes 195
Linear Electron Flow 197
Cyclic Electron Flow 198
A Comparison of Chemiosmosis in Chloroplasts and Mitochondria 199
CONCEPT 10.4 The Calvin cycle uses the chemical energy of ATP and NADPH to reduce CO2 to sugar 201
CONCEPT 10.5 Alternative mechanisms of carbon fixation have evolved in hot, arid climates 203
Photorespiration: An Evolutionary Relic? 203
C4 Plants 203
CAM Plants 205
CONCEPT 10.6 Photosynthesis is essential for life on Earth: a review 206
11 Cell Communication 212
CONCEPT 11.1 External signals are converted to responses
within the cell 213
Evolution of Cell Signaling 213
Local and Long-Distance Signaling 215
The Three Stages of Cell Signaling: A Preview 216
CONCEPT 11.2 Signal reception: A signaling molecule binds to
a receptor, causing it to change shape 217
Receptors in the Plasma Membrane 217
Intracellular Receptors 220
CONCEPT 11.3 Signal transduction: Cascades of molecular
interactions transmit signals from receptors to relay molecules
in the cell 221
Signal Transduction Pathways 221
Protein Phosphorylation and Dephosphorylation 222
Small Molecules and Ions as Second Messengers 223
CONCEPT 11.4 Cellular response: Cell signaling leads to
regulation of transcription or cytoplasmic activities 226
Nuclear and Cytoplasmic Responses 226
Regulation of the Response 226
CONCEPT 11.5 Apoptosis requires integration of multiple
cell-signaling pathways 229
Apoptosis in the Soil Worm Caenorhabditis elegans 230
Apoptotic Pathways and the Signals That Trigger Them 230
12 The Cell Cycle 234
CONCEPT 12.1 Most cell division results in genetically
identical daughter cells 235
Key Roles of Cell Division 235
Cellular Organization of the Genetic Material 235
Distribution of Chromosomes During Eukaryotic Cell Division 236
CONCEPT 12.2 The mitotic phase alternates with interphase in
the cell cycle 237
Phases of the Cell Cycle 237
The Mitotic Spindle: A Closer Look 240
Cytokinesis: A Closer Look 241
Binary Fission in Bacteria 242
The Evolution of Mitosis 243
CONCEPT 12.3 The eukaryotic cell cycle is regulated by a
molecular control system 244
The Cell Cycle Control System 244
Loss of Cell Cycle Controls in Cancer Cells 248
Unit 3 Genetics 253
Interview: Francisco Mojica 253
13 Meiosis and Sexual Life Cycles 254
CONCEPT 13.1 Offspring acquire genes from parents by
inheriting chromosomes 255
Inheritance of Genes 255
Comparison of Asexual and Sexual Reproduction 255
CONCEPT 13.2 Fertilization and meiosis alternate in sexual life
cycles 256
Sets of Chromosomes in Human Cells 256
Behavior of Chromosome Sets in the Human Life Cycle 257
The Variety of Sexual Life Cycles 258
CONCEPT 13.3 Meiosis reduces the number of chromosome
sets from diploid to haploid 259
The Stages of Meiosis 259
Crossing Over and Synapsis During Prophase I 262
A Comparison of Mitosis and Meiosis 262
CONCEPT 13.4 Genetic variation produced in sexual life cycles
contributes to evolution 265
Origins of Genetic Variation Among Offspring 265
The Evolutionary Significance of Genetic Variation Within
Populations 266
14 Mendel and the Gene Idea 269
CONCEPT 14.1 Mendel used the scientific approach to
identify two laws of inheritance 270
Mendel’s Experimental,
Quantitative Approach 270
The Law of Segregation 271
The Law of Independent
Assortment 274
CONCEPT 14.2 Probability
laws govern Mendelian
inheritance 276
The Multiplication and Addition
Rules Applied to Monohybrid
Crosses 277
Solving Complex Genetics Problems with the Rules
of Probability 277
CONCEPT 14.3 Inheritance patterns are often more
complex than predicted by simple Mendelian
genetics 278
Extending Mendelian Genetics for a Single Gene 278
Extending Mendelian Genetics for Two or More Genes 281
Nature and Nurture: The Environmental Impact on
Phenotype 282
A Mendelian View of Heredity and Variation 282
CONCEPT 14.4 Many human traits follow Mendelian
patterns of inheritance 284
Pedigree Analysis 284
Recessively Inherited Disorders 285
Dominantly Inherited Disorders 287
Multifactorial Disorders 287
Genetic Testing and Counseling 287
15 The Chromosomal Basis of
Inheritance 294
CONCEPT 15.1 Mendelian inheritance has its physical basis in
the behavior of chromosomes 295
Morgan’s Choice of Experimental Organism 295
Correlating Behavior of a Gene’s Alleles with Behavior of a
Chromosome Pair: Scientific Inquiry 295
CONCEPT 15.2 Sex-linked genes exhibit unique patterns of
inheritance 298
The Chromosomal Basis of Sex 298
Inheritance of X-Linked Genes 299
X Inactivation in Female Mammals 300
CONCEPT 15.3 Linked genes tend to be inherited together
because they are located near each other on the same chromosome 301
How Linkage Affects Inheritance 301
Genetic Recombination and Linkage 302
Mapping the Distance Between Genes Using Recombination Data:
Scientific Inquiry 305
CONCEPT 15.4 Alterations of chromosome number or
structure cause some genetic disorders 306
Abnormal Chromosome Number 307
Alterations of Chromosome Structure 307
Human Conditions Due to Chromosomal Alterations 308
CONCEPT 15.5 Some inheritance patterns are exceptions to
standard Mendelian inheritance 310
Genomic Imprinting 310
Inheritance of Organelle Genes 311
xxxvi DETAILED CONTENTS
16 The Molecular Basis of
Inheritance 314
CONCEPT 16.1 DNA is the genetic material 315
The Search for the Genetic Material: Scientific Inquiry 315
Building a Structural Model of DNA 317
CONCEPT 16.2 Many proteins work together in DNA
replication and repair 320
The Basic Principle: Base Pairing to a Template Strand 321
DNA Replication: A Closer Look 322
Proofreading and Repairing DNA 327
Evolutionary Significance of Altered DNA Nucleotides 328
Replicating the Ends of DNA Molecules 328
CONCEPT 16.3 A chromosome consists of a DNA molecule
packed together with proteins 330
17 Gene Expression: From Gene to
Protein 335
CONCEPT 17.1 Genes specify proteins via transcription and
translation 336
Evidence from Studying Metabolic Defects 336
Basic Principles of Transcription and Translation 337
The Genetic Code 340
CONCEPT 17.2 Transcription is the DNA-directed synthesis of
RNA: A Closer Look 342
Molecular Components of Transcription 342
Synthesis of an RNA Transcript 342
CONCEPT 17.3 Eukaryotic cells modify RNA after
transcription 345
Alteration of mRNA Ends 345
Split Genes and RNA Splicing 345
CONCEPT 17.4 Translation is the RNA-directed synthesis of a
polypeptide: A Closer Look 347
Molecular Components of Translation 348
Building a Polypeptide 350
Completing and Targeting the Functional Protein 352
Making Multiple Polypeptides in Bacteria and Eukaryotes 355
CONCEPT 17.5 Mutations of one or a few nucleotides can
affect protein structure and function 357
Types of Small-Scale Mutations 357
New Mutations and Mutagens 360
Using CRISPR to Edit Genes and Correct Disease-Causing
Mutations 360
What Is a Gene? Revisiting the Question 361
18 Regulation of Gene Expression 365
CONCEPT 18.1 Bacteria often respond to environmental
change by regulating transcription 366
Operons: The Basic Concept 366
Repressible and Inducible Operons: Two Types of Negative Gene
Regulation 368
Positive Gene Regulation 369
CONCEPT 18. 2 Eukaryotic gene expression is regulated at
many stages 370
Differential Gene Expression 370
Regulation of Chromatin Structure 371
Regulation of Transcription Initiation 373
Mechanisms of Post-transcriptional Regulation 377
CONCEPT 18.3 Noncoding RNAs play multiple roles in
controlling gene expression 379
Effects on mRNAs by MicroRNAs and Small Interfering RNAs 379
Chromatin Remodeling and Effects on Transcription by
ncRNAs 380
CONCEPT 18.4 A program of differential gene expression
leads to the different cell types in a multicellular
organism 381
A Genetic Program for Embryonic Development 381
Cytoplasmic Determinants and Inductive Signals 382
Sequential Regulation of Gene Expression During Cellular
Differentiation 383
Pattern Formation: Setting Up the Body Plan 384
CONCEPT 18.5 Cancer results from genetic changes that affect
cell cycle control 388
Types of Genes Associated with Cancer 388
Interference with Normal Cell-Signaling Pathways 389
The Multistep Model of Cancer Development 391
Inherited Predisposition and Environmental Factors Contributing
to Cancer 394
The Role of Viruses in Cancer 394
CONCEPT 18.5 Cancer results from genetic changes that affect
cell cycle control 388
Types of Genes Associated with Cancer 388
Interference with Normal Cell-Signaling Pathways 389
The Multistep Model of Cancer Development 391
Inherited Predisposition and Environmental Factors Contributing
to Cancer 394
The Role of Viruses in Cancer 394
CONCEPT 20.3 Cloned organisms and stem cells are useful for
basic research and other applications 428
Cloning Plants: Single-Cell Cultures 428
Cloning Animals: Nuclear Transplantation 428
Stem Cells of Animals 430
CONCEPT 20.4 The practical applications of DNA-based
biotechnology affect our lives in many ways 433
Medical Applications 433
Forensic Evidence and Genetic Profiles 436
Environmental Cleanup 437
Agricultural Applications 437
Safety and Ethical Questions Raised by DNA
Technology 438
21 Genomes and Their
Evolution 442
CONCEPT 21.1 The Human Genome Project fostered
development of faster, less expensive sequencing
techniques 443
CONCEPT 21.2 Scientists use bioinformatics to analyze
genomes and their functions 444
Centralized Resources for Analyzing Genome
Sequences 444
Identifying Protein-Coding Genes and Understanding Their
Functions 445
Understanding Genes and Gene Expression at the Systems
Level 446
CONCEPT 21.3 Genomes vary in size, number of genes,
and gene density 448
Genome Size 448
Number of Genes 449
Gene Density and Noncoding DNA 449
CONCEPT 21.4 Multicellular eukaryotes have a lot of
noncoding DNA and many multigene families 450
Transposable Elements and Related Sequences 451
Other Repetitive DNA, Including Simple Sequence DNA 452
Genes and Multigene Families 452
CONCEPT 21.5 Duplication, rearrangement, and mutation of
DNA contribute to genome evolution 454
Duplication of Entire Chromosome Sets 454
Alterations of Chromosome
Structure 454
Duplication and Divergence of Gene-
Sized Regions
of DNA 455
Rearrangements of Parts of Genes:
Exon Duplication and Exon
Shuffling 456
How Transposable Elements
Contribute to Genome
Evolution 459
CONCEPT 21.6 Comparing genome
sequences provides clues to
evolution and development 459
Comparing Genomes 459
Widespread Conservation
of Developmental
Genes Among Animals 463
Unit 4 Mechanisms of Evolution 467
Interview: Cassandra Extavour 467
22 Descent with Modification:
A Darwinian View of Life 468
CONCEPT 22.1 The Darwinian revolution challenged
traditional views of a young Earth inhabited by unchanging
species 469
Endless Forms Most Beautiful 469
Scala Naturae and Classification of Species 470
Ideas About Change over Time 470
Lamarck’s Hypothesis of Evolution 471
CONCEPT 22.2 Descent with modification by natural selection
explains the adaptations of organisms and the unity and
diversity of life 471
Darwin’s Research 471
Ideas from The Origin of Species 473
Key Features of Natural Selection 476
CONCEPT 22.3 Evolution is supported by an overwhelming
amount of scientific evidence 476
Direct Observations of Evolutionary Change 477
Homology 479
The Fossil Record 481
Biogeography 482
What Is Theoretical About Darwin’s View of Life? 483
Unit 4 Mechanisms of Evolution 467
23 The Evolution of Populations 486
CONCEPT 23.1 Genetic variation makes evolution
possible 487
Genetic Variation 487
Sources of Genetic Variation 488
CONCEPT 23.2 The Hardy-Weinberg equation can be used to
test whether a population is evolving 489
Gene Pools and Allele Frequencies 490
The Hardy-Weinberg Equation 490
CONCEPT 23.3 Natural selection, genetic drift, and gene flow
can alter allele frequencies in a population 493
Natural Selection 494
Genetic Drift 494
Gene Flow 496
CONCEPT 23.4 Natural selection is the only mechanism that
consistently causes adaptive evolution 497
Natural Selection: A Closer Look 497
The Key Role of Natural Selection in Adaptive Evolution 498
Sexual Selection 499
Balancing Selection 500
Why Natural Selection Cannot Fashion Perfect Organisms 501
24 The Origin of Species 506
CONCEPT 24.1 The biological species concept emphasizes
reproductive isolation 507
The Biological Species Concept 507
Other Definitions of Species 510
CONCEPT 24.2 Speciation can take place with or without
geographic separation 511
Allopatric (“Other Country”) Speciation 511
Sympatric (“Same Country”) Speciation 513
Allopatric and Sympatric Speciation: A Review 516
CONCEPT 24.3 Hybrid zones reveal factors that cause
reproductive isolation 516
Patterns Within Hybrid Zones 516
Hybrid Zones and Environmental Change 517
Hybrid Zones over Time 518
CONCEPT 24.4 Speciation can occur rapidly or slowly and can
result from changes in few or many genes 520
The Time Course of Speciation 520
Studying the Genetics of Speciation 522
From Speciation to Macroevolution 523
25 The History of Life on Earth 525
CONCEPT 25.1 Conditions on early Earth made the origin of
life possible 526
Synthesis of Organic Compounds on Early Earth 526
Abiotic Synthesis of Macromolecules 527
Protocells 527
Self-Replicating RNA 528
CONCEPT 25.2 The fossil record
documents the history of life 528
The Fossil Record 529
How Rocks and Fossils Are
Dated 529
The Origin of New Groups of
Organisms 530
CONCEPT 25.3 Key events in life’s
history include the origins of
unicellular and multicellular organisms and the colonization
of land 532
The First Single-Celled Organisms 533
The Origin of Multicellularity 535
The Colonization of Land 536
CONCEPT 25.4 The rise and fall of groups of organisms reflect
differences in speciation and extinction rates 537
Plate Tectonics 538
Mass Extinctions 540
Adaptive Radiations 542
CONCEPT 25.5 Major changes in body form can result from
changes in the sequences and regulation of developmental
genes 544
Effects of Developmental Genes 544
The Evolution of Development 545
CONCEPT 25.6 Evolution is not goal oriented 547
Evolutionary Novelties 547
Evolutionary Trends 548
Unit 5 The Evolutionary History
of Biological Diversity 552
Interview: Penny Chisholm 552
26 Phylogeny and the Tree of Life 553
CONCEPT 26.1 Phylogenies show evolutionary
relationships 554
Binomial Nomenclature 554
Hierarchical Classification 554
Linking Classification and Phylogeny 555
What We Can and Cannot Learn from Phylogenetic
Trees 555
Applying Phylogenies 557
CONCEPT 26.2 Phylogenies are inferred from morphological
and molecular data 558
Morphological and Molecular Homologies 558
Sorting Homology from Analogy 558
Evaluating Molecular Homologies 559
CONCEPT 26.3 Shared characters are used to construct
phylogenetic trees 559
Cladistics 559
Phylogenetic Trees with Proportional Branch Lengths 561
Maximum Parsimony and Maximum Likelihood 562
Phylogenetic Trees as Hypotheses 564
CONCEPT 26.4 An organism’s evolutionary history is
documented in its genome 565
Gene Duplications and Gene Families 565
Genome Evolution 566
CONCEPT 26.5 Molecular clocks help track evolutionary
time 566
Molecular Clocks 566
Applying a Molecular Clock: Dating the Origin
of HIV 567
CONCEPT 26.6 Our understanding of the tree of life
continues to change based on new data 568
From Two Kingdoms to Three Domains 568
The Important Role of Horizontal Gene Transfer 568
27 Bacteria and Archaea 573
CONCEPT 27.1 Structural and functional adaptations
contribute to prokaryotic success 574
Cell-Surface Structures 574
Motility 576
Internal Organization and DNA 577
Reproduction 577
CONCEPT 27.2 Rapid reproduction, mutation, and
genetic recombination promote genetic diversity in
prokaryotes 578
Rapid Reproduction and Mutation 578
Genetic Recombination 579
CONCEPT 27.3 Diverse nutritional and metabolic adaptations
have evolved in prokaryotes 581
The Role of Oxygen in Metabolism 582
Nitrogen Metabolism 582
Metabolic Cooperation 582
CONCEPT 27.4 Prokaryotes have radiated into a diverse set
of lineages 583
An Overview of Prokaryotic Diversity 583
Bacteria 583
Archaea 585
CONCEPT 27.5 Prokaryotes play crucial roles in the
biosphere 586
Chemical Recycling 586
Ecological Interactions 587
CONCEPT 27.6 Prokaryotes have both beneficial and harmful
impacts on humans 587
Mutualistic Bacteria 587
Pathogenic Bacteria 588
Antibiotic Resistance 588
Prokaryotes in Research and Technology 589
28 Protists 593
CONCEPT 28.1 Most eukaryotes are single-celled
organisms 594
Structural and Functional Diversity in Protists 594
Endosymbiosis in Eukaryotic Evolution 594
Four Supergroups of Eukaryotes 597
CONCEPT 28.2 Excavates include protists with modified
mitochondria and protists with unique flagella 597
Diplomonads and Parabasalids 600
Euglenozoans 600
CONCEPT 28.3 SAR is a highly diverse group of protists
defined by DNA similarities 601
Stramenopiles 602
Alveolates 604
Rhizarians 606
CONCEPT 28.4 Red algae and green algae are the closest
relatives of plants 609
Red Algae 609
Green Algae 610
CONCEPT 28.5 Unikonts include protists that are closely
related to fungi and animals 611
Amoebozoans 612
Opisthokonts 613
CONCEPT 28.6 Protists play key roles in ecological
communities 614
Symbiotic Protists 614
Photosynthetic Protists 614
29 Plant Diversity I: How Plants
Colonized Land 618
CONCEPT 29.1 Plants evolved from green algae 619
Evidence of Algal Ancestry 619
Adaptations Enabling the Move to Land 619
Derived Traits of Plants 621
The Origin and Diversification of Plants 621
CONCEPT 29.2 Mosses and other nonvascular plants have life
cycles dominated by gametophytes 623
Bryophyte Gametophytes 624
Bryophyte Sporophytes 625
The Ecological and Economic Importance of Mosses 627
CONCEPT 29.3 Ferns and other seedless vascular plants were
the first plants to grow tall 629
Origins and Traits of Vascular Plants 629
Classification of Seedless Vascular Plants 631
The Significance of Seedless Vascular Plants 633
30 Plant Diversity II: The Evolution of
Seed Plants 636
CONCEPT 30.1 Seeds and pollen grains are key adaptations
for life on land 637
Advantages of Reduced Gametophytes 637
Heterospory: The Rule Among Seed Plants 638
Ovules and Production of Eggs 638
Pollen and Production of Sperm 638
The Evolutionary Advantage of Seeds 639
CONCEPT 30.2 Gymnosperms bear “naked” seeds, typically on
cones 640
The Life Cycle of a Pine 640
Early Seed Plants and the Rise of Gymnosperms 641
Gymnosperm Diversity 641
CONCEPT 30.3 The reproductive
adaptations of angiosperms
include flowers and fruits 644
Characteristics of
Angiosperms 644
Angiosperm Evolution 647
Angiosperm Diversity 649
CONCEPT 30.4 Human welfare
depends on seed plants 651
Products from Seed Plants 651
Threats to Plant Diversity 651
31 Fungi 654
CONCEPT 31.1 Fungi are heterotrophs that feed by
absorption 655
Nutrition and Ecology 655
Body Structure 655
Specialized Hyphae in Mycorrhizal Fungi 656
CONCEPT 31.2 Fungi produce spores through sexual or
asexual life cycles 657
Sexual Reproduction 658
Asexual Reproduction 658
CONCEPT 31.3 The ancestor of fungi was an aquatic, singlecelled,
flagellated protist 659
The Origin of Fungi 659
The Move to Land 660
CONCEPT 31.4 Fungi have radiated into a diverse set of
lineages 660
Cryptomycetes and Microsporidians 661
Zoopagomycetes 662
Mucoromycetes 663
Ascomycetes 663
Basidiomycetes 665
CONCEPT 31.5 Fungi play key roles in nutrient cycling,
ecological interactions, and human welfare 667
Fungi as Decomposers 667
Fungi as Mutualists 667
Practical Uses of Fungi 670
32 An Overview of Animal
Diversity 673
CONCEPT 32.1 Animals are multicellular, heterotrophic
eukaryotes with tissues that develop from embryonic
layers 674
Nutritional Mode 674
Cell Structure and Specialization 674
Reproduction and Development 674
CONCEPT 32.2 The history of animals spans more than half a
billion years 675
Steps in the Origin of Multicellular Animals 675
Neoproterozoic Era (1 Billion–541 Million Years Ago) 676
Paleozoic Era (541–252 Million Years Ago) 677
Mesozoic Era (252–66 Million Years Ago) 679
Cenozoic Era (66 Million Years Ago to the Present) 679
CONCEPT 32.3 Animals can be characterized by body
plans 679
Symmetry 679
Tissues 679
Body Cavities 680
Protostome and Deuterostome Development 681
CONCEPT 32.4 Views of animal phylogeny continue to be
shaped by new molecular and morphological data 682
The Diversification of Animals 682
Future Directions in Animal Systematics 684
33 An Introduction to
Invertebrates 686
CONCEPT 33.1 Sponges are basal animals that lack tissues 690
CONCEPT 33.2 Cnidarians are an ancient phylum of
eumetazoans 691
Medusozoans 692
Anthozoans 693
CONCEPT 33.3 Lophotrochozoans, a clade identified by
molecular data, have the widest range of animal body
forms 694
Flatworms 694
Rotifers and
Acanthocephalans 697
Lophophorates: Ectoprocts
and Brachiopods 698
Molluscs 699
Annelids 703
CONCEPT 33.4 Ecdysozoans
are the most species-rich
animal group 705
Nematodes 705
Arthropods 706
CONCEPT 33.5 Echinoderms and chordates are
deuterostomes 713
Echinoderms 713
Chordates 715
34 The Origin and Evolution of
Vertebrates 718
CONCEPT 34.1 Chordates have a notochord and a dorsal,
hollow nerve cord 719
Derived Characters of Chordates 719
Lancelets 720
Tunicates 721
Early Chordate Evolution 722
CONCEPT 34.2 Vertebrates are chordates that have a
backbone 722
Derived Characters of Vertebrates 722
Hagfishes and Lampreys 723
Early Vertebrate Evolution 724
CONCEPT 34.3 Gnathostomes are vertebrates that have jaws 725
Derived Characters of Gnathostomes 725
Fossil Gnathostomes 726
Chondrichthyans (Sharks, Rays, and Their Relatives) 726
Ray-Finned Fishes and Lobe-Fins 728
CONCEPT 34.4 Tetrapods are gnathostomes that have limbs 730
Derived Characters of Tetrapods 730
The Origin of Tetrapods 731
Amphibians 731
CONCEPT 34.5 Amniotes are tetrapods that have a terrestrially
adapted egg 734
Derived Characters of Amniotes 734
Early Amniotes 735
Reptiles 735
CONCEPT 34.6 Mammals are amniotes that have hair and
produce milk 741
Derived Characters of Mammals 741
Early Evolution of Mammals 741
Monotremes 742
Marsupials 743
Eutherians (Placental Mammals) 744
CONCEPT 34.7 Humans are mammals that have a large brain
and bipedal locomotion 748
Derived Characters of Humans 748
The Earliest Hominins 748
Australopiths 749
Bipedalism 750
Tool Use 750
Early Homo 750
Neanderthals 752
Homo sapiens 753
Unit 6 Plant Form and Function 757
35 Vascular Plant Structure, Growth,
and Development 758
CONCEPT 35.1 Plants have a hierarchical organization
consisting of organs, tissues, and cells 759
Vascular Plant Organs: Roots, Stems, and Leaves 759
Dermal, Vascular, and Ground
Tissues 762
Common Types of Plant Cells 763
CONCEPT 35.2 Different meristems
generate new cells for primary and
secondary growth 766
CONCEPT 35.3 Primary growth
lengthens roots and shoots 768
Primary Growth of Roots 768
Primary Growth of Shoots 769
CONCEPT 35.4 Secondary growth increases the diameter of
stems and roots in woody plants 772
The Vascular Cambium and Secondary Vascular Tissue 773
The Cork Cambium and the Production of Periderm 774
Evolution of Secondary Growth 774
CONCEPT 35.5 Growth, morphogenesis, and cell
differentiation produce the plant body 775
Model Organisms: Revolutionizing the Study of Plants 776
Growth: Cell Division and Cell Expansion 776
Morphogenesis and Pattern Formation 777
Gene Expression and the Control of Cell Differentiation 778
Shifts in Development: Phase Changes 778
Genetic Control of Flowering 779
36 Resource Acquisition and
Transport in Vascular Plants 784
CONCEPT 36.1 Adaptations for acquiring resources were key
steps in the evolution of vascular plants 785
Shoot Architecture and Light Capture 785
Root Architecture and Acquisition of Water and Minerals 787
CONCEPT 36.2 Different mechanisms transport substances
over short or long distances 787
The Apoplast and Symplast: Transport Continuums 787
Short-Distance Transport of Solutes Across Plasma
Membranes 788
Short-Distance Transport of Water Across Plasma Membranes 788
Long-Distance Transport:The Role of Bulk Flow 791
CONCEPT 36.3 Transpiration drives the transport of water and
minerals from roots to shoots via the xylem 792
Absorption of Water and Minerals by Root Cells 792
Transport of Water and Minerals into the Xylem 792
Bulk Flow Transport via the Xylem 792
Xylem Sap Ascent by Bulk Flow: A Review 796
CONCEPT 36.4 The rate of transpiration is regulated by
stomata 796
Stomata: Major Pathways for Water Loss 796
Mechanisms of Stomatal Opening and Closing 797
Stimuli for Stomatal Opening and Closing 798
Effects of Transpiration on Wilting and Leaf Temperature 798
Adaptations That Reduce Evaporative Water Loss 798
CONCEPT 36.5 Sugars are transported from sources to sinks
via the phloem 799
Movement from Sugar Sources to Sugar Sinks 799
Bulk Flow by Positive Pressure: The Mechanism of Translocation in
Angiosperms 800
CONCEPT 36.6 The symplast is highly dynamic 801
Changes in Plasmodesmatal Number and Pore Size 802
Phloem: An Information Superhighway 802
Electrical Signaling in the Phloem 802
37 Soil and Plant Nutrition 805
CONCEPT 37.1 Soil contains a living, complex
ecosystem 806
Soil Texture 806
Topsoil Composition 806
Soil Conservation and Sustainable Agriculture 807
CONCEPT 37.2 Plant roots absorb many types of essential
elements from the soil 809
Essential Elements 810
Symptoms of Mineral Deficiency 810
Global Climate Change and Food Quality 812
CONCEPT 37.3 Plant nutrition often involves relationships
with other organisms 812
Bacteria and Plant Nutrition 814
Fungi and Plant Nutrition 817
Epiphytes, Parasitic Plants, and Carnivorous Plants 818
38 Angiosperm Reproduction
and Biotechnology 822
CONCEPT 38.1 Flowers, double fertilization,
and fruits are key features of the angiosperm
life cycle 823
Flower Structure and Function 823
Methods of Pollination 825
The Angiosperm Life Cycle: An Overview 826
Development of Female Gametophytes
(Embryo Sacs) 826
Development of Male Gametophytes in Pollen
Grains 826
Seed Development and Structure 828
Sporophyte Development from Seed to Mature Plant 829
Fruit Structure and Function 830
CONCEPT 38.2 Flowering plants reproduce sexually, asexually,
or both 833
Mechanisms of Asexual Reproduction 833
Advantages and Disadvantages of Asexual and Sexual
Reproduction 833
Mechanisms That Prevent Self-Fertilization 834
Totipotency, Vegetative Reproduction, and Tissue Culture 835
CONCEPT 38.3 People modify crops by breeding and genetic
engineering 836
Plant Breeding 837
Plant Biotechnology and Genetic Engineering 837
The Debate over Plant Biotechnology 839
39 Plant Responses to Internal
and External Signals 842
CONCEPT 39.1 Signal transduction pathways link signal
reception to response 843
Reception 844
Transduction 844
Response 845
CONCEPT CHECK 39.2 Plants use chemicals to communicate 845
General Characteristics of Plant Hormones 846
A Survey of Plant Hormones 847
CONCEPT 39.3 Responses to light are critical for plant
success 855
Blue-Light Photoreceptors 855
Phytochrome Photoreceptors 856
Biological Clocks and Circadian Rhythms 857
The Effect of Light on the Biological Clock 858
Photoperiodism and Responses to Seasons 859
CONCEPT 39.4 Plants respond to a wide variety of stimuli
other than light 861
Gravity 861
Mechanical Stimuli 861
Environmental Stresses 862
CONCEPT 39.5 Plants respond to attacks by pathogens and
herbivores 866
Defenses Against Pathogens 866
Defenses Against Herbivores 867
Unit 7 Animal Form and Function 872
Interview: Steffanie Strathdee 872
40 Basic Principles of Animal Form
and Function 873
CONCEPT 40.1 Animal form and function are correlated at all
levels of organization 874
Evolution of Animal Size and Shape 874
Exchange with the Environment 874
Hierarchical Organization of Body Plans 876
Coordination and Control 880
CONCEPT 40.2 Feedback control maintains the internal
environment in many animals 881
Regulating and Conforming 881
Homeostasis 881
CONCEPT 40.3 Homeostatic processes for thermoregulation
involve form, function, and behavior 884
Endothermy and Ectothermy 884
Variation in Body Temperature 884
Balancing Heat Loss and Gain 885
Acclimatization in Thermoregulation 888
Physiological Thermostats and Fever 888
CONCEPT 40.4 Energy requirements are related to animal
size, activity, and environment 889
Energy Allocation and Use 889
Quantifying Energy Use 890
Minimum Metabolic Rate and Thermoregulation 890
Influences on Metabolic Rate 891
Torpor and Energy Conservation 892
41 Animal Nutrition 898
CONCEPT 41.1 An animal’s diet must supply chemical energy,
organic building blocks, and essential nutrients 899
Essential Nutrients 899
Variation in Diet 901
Dietary Deficiencies 901
Assessing Nutritional Needs 902
CONCEPT 41.2 Food processing involves ingestion, digestion,
absorption, and elimination 902
Digestive Compartments 904
CONCEPT 41.3 Organs specialized for sequential stages
of food processing form the mammalian digestive
system 905
The Oral Cavity, Pharynx, and Esophagus 905
Digestion in the Stomach 907
Digestion in the Small Intestine 908
Absorption in the Small Intestine 909
Processing in the Large Intestine 910
CONCEPT 41.4 Evolutionary adaptations of vertebrate
digestive systems correlate with diet 911
Dental Adaptations 911
Stomach and Intestinal Adaptations 912
Mutualistic Adaptations 912
CONCEPT 41.5 Feedback circuits regulate digestion,
energy storage, and appetite 915
Regulation of Digestion 915
Regulation of Energy Storage 915
Regulation of Appetite and Consumption 917
42 Circulation and Gas Exchange 921
CONCEPT 42.1 Circulatory systems link exchange surfaces
with cells throughout the body 922
Gastrovascular Cavities 922
Open and Closed Circulatory Systems 923
Organization of Vertebrate Circulatory Systems 924
CONCEPT 42.2 Coordinated cycles of heart contraction drive
double circulation in mammals 926
Mammalian Circulation 926
The Mammalian Heart: A Closer Look 926
Maintaining the Heart’s Rhythmic Beat 928
CONCEPT 42.3 Patterns of blood pressure and flow reflect the
structure and arrangement of blood vessels 929
Blood Vessel Structure and Function 929
Blood Flow Velocity 930
Blood Pressure 930
Capillary Function 932
Fluid Return by the Lymphatic System 933
CONCEPT 42.4 Blood components function in exchange,
transport, and defense 934
Blood Composition and Function 934
Cardiovascular Disease 937
CONCEPT 42.5 Gas exchange occurs across specialized
respiratory surfaces 939
Partial Pressure Gradients in Gas Exchange 939
Respiratory Media 939
Respiratory Surfaces 940
Gills in Aquatic Animals 940
Tracheal Systems in Insects 941
Lungs 942
CONCEPT 42.6 Breathing ventilates the lungs 944
How an Amphibian Breathes 944
How a Bird Breathes 944
How a Mammal Breathes 945
Control of Breathing in Humans 946
CONCEPT 42.7 Adaptations for gas exchange include
pigments that bind and transport gases 947
Coordination of Circulation and Gas Exchange 947
Respiratory Pigments 947
Respiratory Adaptations of Diving Mammals 949
43 The Immune System 952
CONCEPT 43.1 In innate immunity, recognition and response
rely on traits common to groups of pathogens 953
Innate Immunity of Invertebrates 953
Innate Immunity of Vertebrates 954
Evasion of Innate Immunity by Pathogens 957
CONCEPT 43.2 In adaptive immunity, receptors provide
pathogen-specific recognition 957
Antigens as the Trigger for Adaptive Immunity 958
Antigen Recognition by B Cells and Antibodies 958
Antigen Recognition by T Cells 959
B Cell and T Cell Development 960
CONCEPT 43.3 Adaptive immunity defends against infection
of body fluids and body cells 963
Helper T Cells: Activating Adaptive Immunity 963
B Cells and Antibodies: A Response to Extracellular Pathogens 964
Cytotoxic T Cells: A Response to Infected Host Cells 966
Summary of the Humoral and Cell-Mediated Immune
Responses 967
Immunization 968
Active and Passive Immunity 968
Antibodies as Tools 969
Immune Rejection 969
CONCEPT 43.4 Disruptions in immune system function can
elicit or exacerbate disease 970
Exaggerated, Self-Directed, and Diminished Immune
Responses 970
Evolutionary Adaptations of Pathogens That Underlie Immune
System Avoidance 971
Cancer and Immunity 974
44 Osmoregulation and
Excretion 977
CONCEPT 44.1 Osmoregulation balances the uptake and loss
of water and solutes 978
Osmosis and Osmolarity 978
Osmoregulatory Challenges and Mechanisms 978
Energetics of Osmoregulation 980
Transport Epithelia in Osmoregulation 981
CONCEPT 44.2 An animal’s nitrogenous wastes reflect its
phylogeny and habitat 982
Forms of Nitrogenous Waste 982
The Influence of Evolution and Environment on Nitrogenous
Wastes 983
CONCEPT 44.3 Diverse excretory systems are variations on a
tubular theme 983
Survey of Excretory Systems 984
CONCEPT 44.4 The nephron is organized for stepwise
processing of blood filtrate 987
From Blood Filtrate to Urine: A Closer Look 987
Solute Gradients and Water Conservation 989
Adaptations of the Vertebrate Kidney to Diverse
Environments 991
CONCEPT 44.5 Hormonal circuits link kidney function, water
balance, and blood pressure 994
Homeostatic Regulation of the Kidney 994
45 Hormones and the Endocrine
System 999
CONCEPT 45.1 Hormones and other signaling molecules
bind to target receptors, triggering specific response
pathways 1000
Intercellular Information Flow 1000
Chemical Classes of Hormones 1001
Cellular Hormone Response Pathways 1002
Endocrine Tissues and Organs 1003
CONCEPT 45.2 Feedback regulation and coordination with the
nervous system are common in hormone pathways 1004
Simple Endocrine Pathways 1004
Simple Neuroendocrine Pathways 1005
Feedback Regulation 1005
Coordination of the Endocrine and Nervous Systems 1006
Thyroid Regulation: A Hormone Cascade Pathway 1008
Hormonal Regulation of Growth 1009
CONCEPT 45.3 Endocrine glands respond to diverse
stimuli in regulating homeostasis, development, and
behavior 1011
Parathyroid Hormone and Vitamin D: Control of Blood
Calcium 1011
Adrenal Hormones: Response to Stress 1012
Sex Hormones 1014
Hormones and Biological Rhythms 1015
Evolution of Hormone Function 1015
46 Animal Reproduction 1019
CONCEPT 46.1 Both asexual and sexual reproduction occur in
the animal kingdom 1020
Mechanisms of Asexual Reproduction 1020
Variation in Patterns of Sexual Reproduction 1020
Reproductive Cycles 1021
Sexual Reproduction: An Evolutionary Enigma 1021
CONCEPT 46.2 Fertilization depends on mechanisms that
bring together sperm and eggs of the same species 1022
Ensuring the Survival of Offspring 1023
Gamete Production and Delivery 1023
CONCEPT 46.3 Reproductive organs produce and transport
gametes 1025
Human Male Reproductive Anatomy 1025
Human Female Reproductive Anatomy 1026
Gametogenesis 1027
CONCEPT 46.4 The interplay of tropic and sex hormones
regulates reproduction in mammals 1030
Biological Sex, Gender Identity, and Sexual Orientation in Human
Sexuality 1031
Hormonal Control of the Male Reproductive System 1031
Hormonal Control of Female Reproductive Cycles 1032
Human Sexual Response 1034
CONCEPT 46.5 In placental mammals, an embryo develops
fully within the mother’s uterus 1034
Conception, Embryonic Development, and Birth 1034
Maternal Immune Tolerance of the Embryo and Fetus 1037
Contraception and Abortion 1037
Modern Reproductive Technologies 1039
47 Animal Development 1043
CONCEPT 47.1 Fertilization and cleavage initiate embryonic
development 1044
Fertilization 1044
Cleavage 1046
CONCEPT 47.2 Morphogenesis in animals involves specific
changes in cell shape, position, and survival 1049
Gastrulation 1049
Developmental Adaptations of Amniotes 1053
Organogenesis 1054
The Cytoskeleton in Morphogenesis 1056
CONCEPT 47.3 Cytoplasmic determinants and inductive
signals regulate cell fate 1057
Fate Mapping 1058
Axis Formation 1059
Restricting Developmental Potential 1060
Cell Fate Determination and Pattern Formation by
Inductive Signals 1061
Cilia and Cell Fate 1064
48 Neurons, Synapses, and
Signaling 1067
CONCEPT 48.1 Neuron structure and organization reflect
function in information transfer 1068
Neuron Structure and Function 1068
Introduction to Information Processing 1068
CONCEPT 48.2 Ion pumps and ion channels establish the
resting potential of a neuron 1069
Formation of the Resting Potential 1070
Modeling the Resting Potential 1071
CONCEPT 48.3 Action potentials are the signals conducted by
axons 1072
Hyperpolarization and Depolarization 1072
Graded Potentials and Action Potentials 1073
Generation of Action Potentials: A Closer Look 1073
Conduction of Action Potentials 1075
CONCEPT 48.4 Neurons communicate with other cells at
synapses 1077
Generation of Postsynaptic Potentials 1078
Summation of Postsynaptic Potentials 1079
Termination of Neurotransmitter Signaling 1079
Modulated Signaling at Synapses 1080
Neurotransmitters 1080
49 Nervous Systems 1085
CONCEPT 49.1 Nervous systems consist of circuits of neurons
and supporting cells 1086
Organization of the Vertebrate Nervous System 1087
The Peripheral Nervous System 1088
Glia 1090
CONCEPT 49.2 The vertebrate brain is regionally
specialized 1091
Arousal and Sleep 1094
Biological Clock Regulation 1094
Emotions 1095
Functional Imaging of the Brain 1096
CONCEPT 49.3 The cerebral cortex controls voluntary
movement and cognitive functions 1096
Information Processing 1097
Language and Speech 1098
Lateralization of Cortical Function 1098
Frontal Lobe Function 1098
Evolution of Cognition in Vertebrates 1098
CONCEPT 49.4 Changes in synaptic connections underlie
memory and learning 1099
Neuronal Plasticity 1100
Memory and Learning 1100
Long-Term Potentiation 1101
CONCEPT 49.5 Many nervous system disorders can now be
explained in molecular terms 1102
Schizophrenia 1102
Depression 1102
The Brain’s Reward System and Drug Addiction 1103
Alzheimer’s Disease 1103
Parkinson’s Disease 1104
Future Directions in Brain Research 1104
50 Sensory and Motor
Mechanisms 1107
CONCEPT 50.1 Sensory receptors transduce stimulus
energy and transmit signals to the central nervous
system 1108
Sensory Reception and Transduction 1108
Transmission 1109
Perception 1109
Amplification and Adaptation 1109
Types of Sensory Receptors 1110
CONCEPT 50.2 In hearing and equilibrium, mechanoreceptors detect moving fluid or settling
particles 1112
Sensing of Gravity and Sound in Invertebrates 1112
Hearing and Equilibrium in Mammals 1112
Hearing and Equilibrium in Other Vertebrates 1116
CONCEPT 50.3 The diverse visual receptors of animals depend on light-absorbing pigments 1117
Evolution of Visual Perception 1117
The Vertebrate Visual System 1119
CONCEPT 50.4 The senses of taste and smell rely on similar
sets of sensory receptors 1123
Taste in Mammals 1123
Smell in Humans 1124
CONCEPT 50.5 The physical interaction of protein filaments is required for muscle function 1125
Vertebrate Skeletal Muscle 1126
Other Types of Muscle 1131
CONCEPT 50.6 Skeletal systems transform muscle contraction into locomotion 1132
Types of Skeletal Systems 1132
Types of Locomotion 1135
51 Animal Behavior 1139
CONCEPT 51.1 Discrete sensory inputs can stimulate both simple and complex behaviors 1140
Fixed Action Patterns 1140
Migration 1140
Behavioral Rhythms 1141
Animal Signals and Communication 1141
CONCEPT 51.2 Learning establishes specific links between experience and behavior 1143
Experience and Behavior 1143
Learning 1144
CONCEPT 51.3 Selection for individual survival and reproductive success can explain diverse
behaviors 1148
Evolution of Foraging Behavior 1148
Mating Behavior and Mate Choice 1149
CONCEPT 51.4 Genetic analyses and the concept of inclusive fitness provide a basis for studying the
evolution of behavior 1154
Genetic Basis of Behavior 1155
Genetic Variation and the Evolution of Behavior 1155
Altruism 1156
Inclusive Fitness 1157
Evolution and Human Culture 1159
Unit 8 Ecology 1163
Interview: Chelsea Rochman 1163
52 An Introduction to Ecology and the Biosphere 1164
CONCEPT 52.1 Earth’s climate varies by latitude and season and is changing rapidly 1167
Global Climate Patterns 1167
Regional and Local Effects on Climate 1167
Effects of Vegetation on Climate 1169
Microclimate 1169
Global Climate Change 1170
CONCEPT 52.2 The distribution of terrestrial biomes is controlled by climate and disturbance 1171
Climate and Terrestrial Biomes 1171
General Features of Terrestrial Biomes 1172
Disturbance and Terrestrial Biomes 1172
CONCEPT 52.3 Aquatic biomes are diverse and dynamic systems that cover most of Earth 1177
Zonation in Aquatic Biomes 1177
CONCEPT 52.4 Interactions between organisms and the environment limit the distribution of species 1178
Dispersal and Distribution 1183
Biotic Factors 1184
Abiotic Factors 1184
CONCEPT 52.5 Ecological change and evolution affect one another over long and short periods of time 1187
53 Population Ecology 1190
CONCEPT 53.1 Biotic and abiotic factors affect population density, dispersion, and demographics 1191
Density and Dispersion 1191
Demographics 1193
CONCEPT 53.2 The exponential model describes population growth in an idealized, unlimited
environment 1196
Changes in Population Size 1196
Exponential Growth 1196
CONCEPT 53.3 The logistic model describes how a population grows more slowly as it nears its
carrying capacity 1197
The Logistic Growth Model 1198
The Logistic Model and Real Populations 1199
CONCEPT 53.4 Life history traits are products of natural selection 1200
Diversity of Life Histories 1200
“Trade-offs” and Life Histories 1201
CONCEPT 53.5 Density-dependent factors regulate population growth 1202
Population Change and Population Density 1202
Mechanisms of Density-Dependent
Population Regulation 1203
Population Dynamics 1205
CONCEPT 53.6 The human population is no longer growing exponentially but is still increasing
extremely rapidly 1207
The Global Human Population 1207
Global Carrying Capacity 1209
54 Community Ecology 1214
CONCEPT 54.1 Interactions between species can help, harm, or have no effect on the individuals
involved 1215
Competition 1215
Exploitation 1217
Positive Interactions 1220
CONCEPT 54.2 Diversity and trophic structure characterize biological communities 1222
Species Diversity 1222
Diversity and Community Stability 1223
Trophic Structure 1223
Species with a Large Impact 1225
Bottom-Up and Top-Down Controls 1226
CONCEPT 54.3 Disturbance influences species diversity and composition 1228
Characterizing Disturbance 1228
Ecological Succession 1229
Human Disturbance 1231
CONCEPT 54.4 Biogeographic factors affect community diversity 1231
Latitudinal Gradients 1232
Area Effects 1232
Island Equilibrium Model 1232
CONCEPT 54.5 Pathogens alter community structure locally and globally 1234
Effects on Community Structure 1234
Community Ecology and Zoonotic Diseases 1234
55 Ecosystems and Restoration
Ecology 1238
CONCEPT 55.1 Physical laws govern energy flow and chemical
cycling in ecosystems 1239
Energy Flow and Chemical Cycling 1239
Conservation of Energy 1239
Conservation of Mass 1239
Energy, Mass, and Trophic Levels 1240
CONCEPT 55.2 Energy and other limiting factors control primary production in ecosystems 1241
Ecosystem Energy Budgets 1241
Primary Production in Aquatic Ecosystems 1242
Primary Production in Terrestrial Ecosystems 1243
CONCEPT 55.3 Energy transfer between trophic levels is typically only 10% efficient 1246
Production Efficiency 1246
Trophic Efficiency and Ecological Pyramids 1246
CONCEPT 55.4 Biological and geochemical processes cycle
nutrients and water in ecosystems 1248
Decomposition and Nutrient Cycling Rates 1248
Biogeochemical Cycles 1249
Case Study: Nutrient Cycling in the Hubbard Brook Experimental Forest 1252
CONCEPT 55.5 Restoration ecologists return degraded ecosystems to a more natural state 1253
Bioremediation 1253
Biological Augmentation 1255
Ecosystems: A Review 1255
56 Conservation Biology and Global Change 1260
CONCEPT 56.1 Human activities threaten earth’s biodiversity 1261
Three Levels of Biodiversity 1261
Biodiversity and Human Welfare 1262
Threats to Biodiversity 1263
Can Extinct Species Be Resurrected? 1266
CONCEPT 56.2 Population conservation focuses on population size, genetic diversity, and critical
habitat 1266
Extinction Risks in Small Populations 1266
Critical Habitat 1269
Weighing Conflicting Demands 1270
CONCEPT 56.3 Landscape and regional conservation help sustain biodiversity 1270
Landscape Structure and Biodiversity 1270
Establishing Protected Areas 1272
Urban Ecology 1273
CONCEPT 56.4 Earth is changing rapidly as a result of human actions 1274
Nutrient Enrichment 1274
Toxins in the Environment 1275
Greenhouse Gases and Climate Change 1278
Depletion of Atmospheric Ozone 1283
CONCEPT 56.5 Sustainable development can improve human
lives while conserving biodiversity 1284
Sustainable Development 1284
The Future of the Biosphere 1285
APPENDIX A Answers A-1
APPENDIX B Classification of Life B-1
APPENDIXC A Comparison of the Light Microscope and the
Electron Microscope C-1
APPENDIXD Scientific Skills Review D-1
CREDITS CR-1
GLOSSARY G-1
INDEX I-1