About the Authors xvii
Preface xviii
Chapter 1 Introduction: Ecology, Evolution, and the Scientific Method 1
Searching for Life at the Bottom of the Ocean 1
Ecological systems exist in a hierarchy of organization 3
Individuals 3
Populations and Species 3
Communities 5
Ecosystems 5
The Biosphere 6
Studying Ecology at Different Levels of Organization 6
Ecological systems are governed by physical and biological principles 8
Conservation of Matter and Energy 8
Dynamic Steady States 8
Evolution 9
Different organisms play diverse roles in ecological systems 10
Broad Evolutionary Patterns 10
Categorizing Species Based on Sources of Energy 15
Types of Species Interactions 15
Habitat versus Niche 17
Scientists use several approaches to studying ecology 20
Observations, Hypotheses, and Predictions 20
Testing Hypotheses with Manipulative Experiments 21
Alternative Approaches to Manipulative Experiments 23
ANALYZING ECOLOGY
Why Do We Calculate Means and Variances? 24
Humans influence ecological systems 26
The Role of Ecologists 27
ECOLOGY TODAY: CONNECTING THE CONCEPTS
The California Sea Otter 28
PART I LIFE AND THE PHYSICAL ENVIRONMENT
Chapter 2 Adaptations to Aquatic Environments 32
The Evolution of Whales 33
Water has many properties favorable to life 34
Thermal Properties of Water 34
Density and Viscosity of Water 35
Dissolved Inorganic Nutrients 36
Animals and plants face the challenge of water and salt balance 40
Salt Balance in Aquatic Animals 40
Adaptations in Freshwater Animals 41
Adaptations in Saltwater Animals 42
Salt Balance in Aquatic Plants 43
ANALYZING ECOLOGY
Standard Deviation and Standard Error 44
The uptake of gases from water is limited by diffusion 45
Carbon Dioxide 45
Oxygen 47
Temperature limits the occurrence of aquatic life 49
Heat and Biological Molecules 49
Cold Temperatures and Freezing 50
Thermal Optima 51
ECOLOGY TODAY: CONNECTING THE CONCEPTS
The Decline of Coral Reefs 52
GRAPHING THE DATA
Determining Q10 Values in Salmon 55
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Chapter 3 Adaptations to Terrestrial Environments 56
The Evolution of Camels 57
Most terrestrial plants obtain nutrients and water from the soil 58
Soil Nutrients 58
Soil Structure and Water-Holding Capacity 58
Osmotic Pressure and Water Uptake 60
Transpiration and the Cohesion–Tension Theory 62
Sunlight provides the energy for photosynthesis 64
Available and Absorbed Solar Energy 64
Photosynthesis 66
Structural Adaptations to Water Stress 71
Terrestrial environments pose a challenge for animals to balance water, salt, and nitrogen 71
Water and Salt Balance in Animals 72
ANALYZING ECOLOGY
Different Types of Variables 74
Water and Nitrogen Balance in Animals 74
Adaptations to different temperatures allow terrestrial life to exist around the planet 75
Sources of Heat Gain and Loss 75
Body Size and Thermal Inertia 77
Thermoregulation 77
Ectotherms 77
Endotherms 78
Adaptations of the Circulatory System 79
ECOLOGY TODAY: CONNECTING THE CONCEPTS
The Challenge of Growing Cotton 80
GRAPHING THE DATA
Relating Mass to Surface Area and Volume 83
Chapter 4 Adaptations to Variable Environments 84
The Fine-Tuned Phenotypes of Frogs 85
Ecological systems and processes vary in time and space 86
Temporal Variation 87
Spatial Variation 87
Correlation of Spatial and Temporal Dimensions 88
Environmental variation favors the evolution of variable phenotypes 89
Phenotypic Tradeoffs 89
Environmental Cues 91
Response Speed and Reversibility 91
Many organisms have evolved adaptations to variation in enemies, competitors, and mates 92
Enemies 92
Competition for Scarce Resources 93
Mates 94
Many organisms have evolved adaptations to variable abiotic conditions 95
Temperature 95
Water Availability 97
Salinity 98
Oxygen 98
Migration, storage, and dormancy are strategies to survive extreme environmental variation 99
Migration 99
Storage 100
Dormancy 100
ANALYZING ECOLOGY
Correlations 102
Adaptations to Prevent Freezing 103
Variation in food quality and quantity is the basis of optimal foraging theory 103
Central Place Foraging 104
Risk-Sensitive Foraging 105
Optimal Diet Composition 107
Diet Mixing 107
ECOLOGY TODAY: CONNECTING THE CONCEPTS
Responding to Novel Environmental Variation 108
GRAPHING THE DATA
The Foraging Behavior of American Robins 111
Chapter 5 Climates and Soils 112
Where Does Your Garden Grow? 113
Earth is warmed by the greenhouse effect 114
The Greenhouse Effect 114
Greenhouse Gases 115
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There is an unequal heating of Earth by the Sun 116
The Path and Angle of the Sun 116
Seasonal Heating of Earth 117
ANALYZING ECOLOGY
Regressions 118
The unequal heating of Earth drives air currents in the atmosphere 119
Properties of Air 119
Formation of Atmospheric Convection Currents 120
Earth’s Rotation and the Coriolis Effect 122
Ocean currents also affect the distribution of climates 123
Gyres 124
Upwelling 125
The El Niño–Southern Oscillation 125
Thermohaline Circulation 126
Smaller-scale geographic features can affect regional and local climates 127
Continental Land Area 127
Proximity to Coasts 127
Rain Shadows 128
Climate and the underlying bedrock interact to create a diversity of soils 129
Soil Formation 129
Weathering 130
ECOLOGY TODAY: CONNECTING THE CONCEPTS
Global Climate Change 133
GRAPHING THE DATA
Creating a Climate Diagram 135
Chapter 6 Terrestrial and Aquatic Biomes 136
The World of Wine 137
Terrestrial biomes are categorized by their major plant growth forms 138
Climate Diagrams 140
ANALYZING ECOLOGY
Mean, Median, and Mode 141
There are nine categories of terrestrial biomes 141
Tundras 142
Boreal Forests 142
Temperate Rainforests 143
Temperate Seasonal Forests 144
Woodlands/Shrublands 145
Temperate Grasslands/Cold Deserts 145
Tropical Rainforests 146
Tropical Seasonal Forests/Savannas 147
Subtropical Deserts 148
Aquatic biomes are categorized by their flow, depth, and salinity 148
Streams and Rivers 148
Ponds and Lakes 149
Freshwater Wetlands 152
Salt Marshes/Estuaries 153
Mangrove Swamps 153
Intertidal Zones 154
Coral Reefs 154
The Open Ocean 154
ECOLOGY TODAY: CONNECTING THE CONCEPTS
Changing Biome Boundaries 156
GRAPHING THE DATA
Building Bar Graphs 159
PART II ORGANISMS
Chapter 7 Evolution and Adaptation 160
Darwin’s Finches 161
The process of evolution depends on genetic variation 162
The Structure of DNA 162
Genes and Alleles 162
Dominant and Recessive Alleles 163
Sources of Genetic Variation 164
Evolution can occur through random processes or through selection 165
Evolution Through Random Processes 166
Evolution Through Selection 169
ANALYZING ECOLOGY
Strength of Selection, Heritability, and Response to Selection 172
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Microevolution operates at the population level 173
Artificial Selection 173
Natural Selection 174
Macroevolution operates at the species level and higher levels of taxonomic organization 176
Phylogenetic Trees 177
Allopatric Speciation 178
Sympatric Speciation 178
Key Innovations 180
ECOLOGY TODAY: CONNECTING THE CONCEPTS
Drug-Resistant Tuberculosis 181
GRAPHING THE DATA
Natural Selection on Finch Beaks 183
Chapter 8 Life Histories 184
Live, Breed, and Die 185
Life history traits represent the schedule of an organism’s life 186
The Slow-to-Fast Life History Continuum 186
Combinations of Life History Traits in Plants 187
Life history traits are shaped by trade-offs 189
The Principle of Allocation 189
Offspring Number versus Offspring Size 189
ANALYZING ECOLOGY
Coefficients of Determination 190
Offspring Number versus Parental Care 191
Fecundity and Parental Care versus Parental Survival 192
Growth versus Age of Sexual Maturity and Life Span 193
Organisms differ in the number of times that they reproduce, but they eventually become senescent 195
Semelparity and Iteroparity 195
Senescence 197
Life histories are sensitive to environmental conditions 198
Stimuli for Change 198
The Effects of Resources 199
Effects of Predation 200
Effects of Global Warming 200
ECOLOGY TODAY: CONNECTING THE CONCEPTSSelecting On Life Histories With Commercial Fishing 203
GRAPHING THE DATA
Lizard Offspring Number versus Offspring Mass 205
Chapter 9 Reproductive Strategies 206
The Sex Life of Honeybees 207
Reproduction can be sexual or asexual 208
Sexual Reproduction 208
Asexual Reproduction 208
Costs of Sexual Reproduction 210
Benefits of Sexual Reproduction 211
Organisms can evolve as separate sexes or as hermaphrodites 213
Comparing Strategies 215
Selfing versus Outcrossing of Hermaphrodites 216
Mixed Mating Strategies 216
Sex ratios of offspring are typically balanced, but they can be modified by natural selection 216
Mechanisms of Sex Determination 216
Offspring Sex Ratio 218
ANALYZING ECOLOGY
Frequency-Dependent Selection 219
Mating systems describe the pattern of mating between males and females 220
Promiscuity 221
Polygamy 221
Monogamy 222
Sexual selection favors traits that facilitate reproduction 223
Sexual Dimorphism 223
The Evolution of Female Choice 224
Runaway Sexual Selection 225
The Handicap Principle 226
Sexual Conflict 226
ECOLOGY TODAY: CONNECTING THE CONCEPTS
Male-hating Microbes 227
GRAPHING THE DATA
Frequency-Dependent Selection 229
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Chapter 10 Social Behaviors 230
The Life of a Fungus Farmer 231
Living in groups has costs and benefits 232
Benefits of Living in Groups 233
Costs of Living in Groups 234
Territories 235
Dominance Hierarchies 236
There are many types of social interactions 236
The Types of Social Interactions 236
Altruism and Kin Selection 237
ANALYZING ECOLOGY
Calculating Inclusive Fitness 239
Eusocial species take social interactions to the extreme 240
Eusociality in Ants, Bees, and Wasps 240
Eusociality in Other Species 242
The Origins of Eusociality 242
ECOLOGY TODAY: CONNECTING THE CONCEPTS
Hen-Pecked Chickens 243
GRAPHING THE DATA
How Living In Groups Affects Predation Risk 245
PART III POPULATIONS
Chapter 11 Population Distributions 246
Bringing Back the Mountain Boomer 247
The distribution of populations is limited to ecologically suitable habitats 249
Determining Suitable Habitats 249
Ecological Niche Modeling 250
Habitat Suitability and Global Warming 252
Population distributions have five important characteristics 253
Geographic Range 254
Abundance 254
Density 254
Dispersion 255
Dispersal 256
The distribution properties of populations can be estimated 256
Quantifying the Location and Number of Individuals 256
ANALYZING ECOLOGY
Mark-Recapture Surveys 258
Quantifying the Dispersal of Individuals 258
Population abundance and density are related to geographic range and adult body size 259
Population Abundance and Geographic Range 260
Population Density and Adult Body Size 260
Dispersal is essential to colonizing new areas 261
Dispersal Limitation 261
Habitat Corridors 261
Many populations live in distinct patches of habitat 263
The Ideal Free Distribution Among Habitats 263
Conceptual Models of Spatial Structure 265
ECOLOGY TODAY: CONNECTING THE CONCEPTS
The Invasion of the Emerald Ash Borer 267
GRAPHING THE DATA
An Ideal Free Distribution 269
Chapter 12 Population Growth and Regulation 270
The Human Population Explosion 271
Under ideal conditions, populations can grow rapidly 272
The Exponential Growth Model 272
The Geometric Growth Model 273
Comparing the Exponential and Geometric
Growth Models 274
Population Doubling Time 275
Populations have growth limits 276
Density-Independent Factors 276
Density-Dependent Factors 277
Positive Density Dependence 278
The Logistic Growth Model 281
Predicting Human Population Growth with the Logistic Equation 283
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Population growth rate is influenced by the proportions of individuals in different age, size, and life history classes 283
Age Structure 283
Survivorship Curves 285
Life Tables 285
Collecting Data for Life Tables 288
ANALYZING ECOLOGY
Calculating Life Table Values 289
ECOLOGY TODAY: CONNECTING THE CONCEPTS
Saving The Sea Turtles 291
GRAPHING THE DATA
Survivorship Curves 293
Chapter 13 Population Dynamics over
Space and Time 294
Monitoring Moose in Michigan 295
Populations fluctuate naturally over time 296
Age Structure Fluctuations 297
Overshoots and Die-offs 298
Cyclic Population Fluctuations 300
Density dependence with time delays can cause populations to be inherently cyclic 300
The Inherent Cycling Behavior of Populations 300
Delayed Density Dependence 301
ANALYZING ECOLOGY
Delayed Density Dependence in the Flixweed 303
Cycles in Laboratory Populations 303
Chance events can cause small populations to go extinct 305
Extinction in Small Populations 306
Extinction Due to Variation in
Population Growth Rates 307
Metapopulations are composed of subpopulations that can experience independent population dynamics across space 308
The Fragmented Nature of Habitats 308
The Basic Model of Metapopulation Dynamics 309
Observing Metapopulation Dynamics in Nature 310
The Importance of Patch Size and Patch Isolation 310
ECOLOGY TODAY: CONNECTING THE CONCEPTS
The Recovery of the Black-footed Ferret 313
GRAPHING THE DATA
Exploring the Equilibrium of the Basic Metapopulation Model 315
PART IV SPECIES INTERACTIONS
Chapter 14 Predation and Herbivory 316
A Century-long Mystery of the Lynx and the Hare 317
Predators and herbivores can limit the abundance of populations 319
Predators 319
Mesopredators 320
Herbivores 321
Populations of consumers and consumed populations fluctuate in regular cycles 323
Creating Predator–Prey Cycles in the Laboratory 324
Mathematical Models of Predator–Prey Cycles 325
Functional and Numerical Responses 328
Predation and herbivory favor the evolution of defenses 331
Defenses Against Predators 331
Defenses Against Herbivores 336
ANALYZING ECOLOGY
Understanding Statistical Significance 337
ECOLOGY TODAY: CONNECTING THE CONCEPTS
The Trouble with Cats and Rabbits 339
GRAPHING THE DATA
The Functional Response of Wolves 341
Chapter 15 Parasitism and Infectious Diseases 342
The Life of Zombies 343
Many different types of parasites affect the abundance of host species 345
Ectoparasites 346
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Endoparasites 347
Parasite and host dynamics are determined by the parasite’s ability to infect the host 352
Mechanisms of Parasite Transmission 353
Modes of Entering the Host 354
Jumping Between Species 354
Reservoir Species 354
The Host’s Immune System 354
Parasite and host populations commonly fluctuate in regular cycles 354
Population Fluctuations in Nature 355
Modeling Parasite and Host Populations 356
Parasites have evolved offensive strategies while hosts have evolved defensive strategies 358
Parasite Adaptations 358
Host Adaptations 359
ANALYZING ECOLOGY
Comparing Two Groups with a t-Test 360
Coevolution 360
ECOLOGY TODAY: CONNECTING THE CONCEPTS
Of Mice and Men…and Lyme Disease 362
GRAPHING THE DATA
Time Series Data 365
Chapter 16 Competition 366
The Complexity of Competition 367
Competition occurs when individuals experience limited resources 368
The Role of Resources 369
The Competitive Exclusion Principle 372
The theory of competition is an extension of logistic growth models 374
Competition for a Single Resource 374
Competition for Multiple Resources 378
The outcome of competition can be altered by abiotic conditions, disturbances, and interactions with other species 379
Abiotic Conditions 379
Disturbances 380
Predation and Herbivory 380
Competition can occur through exploitation or direct interference, or it may be apparent competition 381
Interference Competition: Aggressive Interactions 381
Interference Competition: Allelopathy 382
Apparent Competition 382
ANALYZING ECOLOGY
Chi-square Tests 385
ECOLOGY TODAY: CONNECTING THE CONCEPTS
Finding the Forest in the Ferns 386
GRAPHING THE DATA
Competition for a Shared Resource 389
Chapter 17 Mutualism 390
Living with Crabs 391
Mutualisms can improve the acquisition of water, nutrients, and places to live 392
Acquisition of Resources in Plants 394
Acquisition of Resources in Animals 395
Mutualisms can aid in defense against enemies 397
Plant Defense 397
Animal Defense 398
Mutualisms can facilitate pollination and seed dispersal 400
Pollination 400
Seed Dispersal 401
Mutualisms can change when conditions change 402
From Positive to Negative Interactions 402
Dealing with Cheaters 403
Mutualisms can affect communities 403
Effects on Species Distributions 404
Effects on Communities 404
ANALYZING ECOLOGY
Comparing Two Groups That Do Not Have Normal Distributions 406
Effects on Ecosystem Function 407
ECOLOGY TODAY: CONNECTING THE CONCEPTS
Dealing with the Death of Dispersers 409
GRAPHING THE DATA
Ecosystem Function of Fungi 411
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PART V COMMUNITIES AND ECOSYSTEMS
Chapter 18 Community Structure 412
A Web of Interactions in Social Spiders 413
Communities can have distinct or gradual boundaries 414
Community Zonation 414
Categorizing Communities 416
Ecotones 416
Communities with Interdependent versus
Independent Species Distributions 418
The diversity of a community incorporates both the number and relative abundance of species 420
Patterns of Abundance Among Species 420
Rank-Abundance Curves 421
ANALYZING ECOLOGY
Calculating Species Diversity 421
Species diversity is affected by resources, habitat diversity, keystone species, and disturbance 421
Resources 424
Habitat Diversity 426
Keystone Species 426
Disturbances 428
Communities are organized into food webs 430
Trophic Levels 430
Direct versus Indirect Effects 431
Top-down and Bottom-up Effects 434
Communities respond to disturbances with resistance, with resilience, or by switching among alternative stable states 435
Community Stability 435
Alternative Stable States 436
ECOLOGY TODAY: CONNECTING THE CONCEPTS
Lethal Effects of Pesticides at Nonlethal Concentrations 438
GRAPHING THE DATA
Log-Normal Distributions and Rank-Abundance Curves 441
Chapter 19 Community Succession 442
Retreating Glaciers in Alaska 443
Succession occurs in a community when species replace each other over time 444
Observing Succession 445
Succession in Terrestrial Environments 447
Succession in Aquatic Environments 450
ANALYZING ECOLOGY
Quantifying Community Similarity 453
Change in Species Diversity 454
Succession can occur through different mechanisms 454
Traits of Early- versus Late-Succession Species 455
Facilitation, Inhibition, and Tolerance 456
Tests for the Mechanisms of Succession 457
Succession does not always produce a single climax community 459
Changes in Climax Communities over Time 459
Changes in Climax Communities over Space 460
Transient Climaxes 460
Creating Gaps in a Climax Community 461
Climax Communities Under Extreme
Environmental Conditions 462
ECOLOGY TODAY: CONNECTING THE CONCEPTS
Promoting Succession on a Strip Mine 463
GRAPHING THE DATA
Species Richness at Glacier Bay 465
Chapter 20 Movement of Energy in Ecosystems 466
Worming Your Way into an Ecosystem 467
Primary productivity provides energy to the ecosystem 468
Primary Productivity 468
Measuring Primary Productivity 470
Secondary Production 472
Net primary productivity differs among ecosystems 474
Primary Productivity Around the World 474
Drivers of Productivity in Terrestrial Ecosystems 474
Drivers of Productivity in Aquatic Ecosystems 476
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The movement of energy depends on the efficiency of energy flow 479
Trophic Pyramids 479
The Efficiencies of Energy Transfers 481
ANALYZING ECOLOGY
Quantifying Trophic Efficiencies 484
Residence Times 484
Stoichiometry 485
ECOLOGY TODAY: CONNECTING THE CONCEPTS
Feeding an Ocean of Whales 487
GRAPHING THE DATA
NPP Versus the Total Primary Productivity of Ecosystems 489
Chapter 21 Movement of Elements in Ecosystems 490
Living in a Dead Zone 491
The hydrologic cycle moves many elements through ecosystems 493
The Hydrologic Cycle 493
Human Impacts on the Hydrologic Cycle 494
The carbon cycle is closely tied to the movement of energy 494
The Carbon Cycle 494
Human Impacts on the Carbon Cycle 496
Nitrogen cycles through ecosystems in many different forms 497
The Nitrogen Cycle 497
Human Impacts on the Nitrogen Cycle 499
The phosphorus cycle moves between land water 500
The Phosphorus Cycle 500
Human Impacts on the Phosphorus Cycle 501
In terrestrial ecosystems, most nutrients regenerate in the soil 501
The Importance of Weathering 502
The Breakdown of Organic Matter 504
Decomposition Rates Among Terrestrial Ecosystems 506
ANALYZING ECOLOGY
Calculating Decomposition Rates of Leaves 507
In aquatic ecosystems, most nutrients regenerate in the sediments 507
Allochthonous Inputs to Streams and Wetlands 508
Decomposition and Sedimentation in Rivers, Lakes, and Oceans 509
Stratification of Lakes and Oceans 509
ECOLOGY TODAY: CONNECTING THE CONCEPTS
Cycling Nutrients in New Hampshire 510
GRAPHING THE DATA
The Decomposition of Organic Matter 513
PART VI GLOBAL ECOLOGY
Chapter 22 Landscape Ecology, Biogeography, and Global Biodiversity 514
The Magnificent Biodiversity of the Cape Floristic Region 515
Landscape ecology examines ecological patterns and processes at large spatial scales 516
Causes of Habitat Heterogeneity 516
Relationships Between Habitat Heterogeneity and Species Diversity 518
Local and Regional Species Diversity 518
The number of species increases with area 519
Species-area Relationships 519
Habitat Fragmentation 521
ANALYZING ECOLOGY
Estimating the Number of Species in an Area 522
The equilibrium theory of island biogeography incorporates both area and isolation 526
The Evidence 526
The Theory 527
Applying the Theory to the Design of Nature Reserves 529
On a global scale, biodiversity is highest near the equator and declines toward the poles 530
Patterns of Diversity 530
Processes that Underlie Patterns of Diversity 531
The distribution of species around the world is affected by Earth’s history 534
Continental Drift 534
Biogeographic Regions 535
Historic Climate Change 536
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ECOLOGY TODAY: CONNECTING THE CONCEPTS
Taking a Long Walk for Conservation 537
GRAPHING THE DATA
Species Accumulation Curves 539
Chapter 23 Global Conservation of Biodiversity 540
Protecting Hotspots of Biodiversity 541
The value of biodiversity arises from social, economic, and ecological considerations 543
Instrumental Values 543
Intrinsic Values 544
Although extinction is a natural process, its current rate is unprecedented 544
Background Extinction Rates 545
A Possible Sixth Mass Extinction 545
Global Declines in Species Diversity 545
Global Declines in Genetic Diversity 548
Human activities are causing the loss of biodiversity 550
Habitat Loss 550
Overharvesting 552
Introduced Species 554
Pollution 556
ANALYZING ECOLOGY
Contaminant Half-Lives 557
Global Climate Change 557
Conservation efforts can slow or reverse declines in biodiversity 559
Habitat Protection 560
Reduced Harvesting 561
Species Reintroductions 562
ECOLOGY TODAY: CONNECTING THE CONCEPTS
Returning Wolves to Yellowstone 563
GRAPHING THE DATA
Stacked Bar Graphs 565
Appendices
Reading Graphs A-1
Statistical Tables A-7
Answers to Analyzing Ecology and Graphing the Data exercises A-11
Suggested Readings A-19
Glossary G-1
Index I-1
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