The of TENTH EDITION

DAVID SADAVA The Claremont Colleges

DAVID M. HILLIS University of Texas

H. CRAIG HELLER Stanford University

MAY R. BERENBAUM University of Illinois

SINAUER MACMILLAN

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PART ONE „ THE SCIENCE OF LIFE AND ITS 29 The of 588 CHEMICAL BASIS 30 The Evolution and Diversity of Fungi 608 1 Studying Life 1 31 Origins and the Evolution of Plans 629 2 Small and the of Life 21 32 Protostome 651 3 , , and 39 33 Deuterostome Animals 678 4 Nucleic and the Origin of Life 62 PART EIGHT „ FLOWERING PLANTS: PART TWO „ CELLS FORM AND 5 Cells: The Working Units of Life 77 34 The Body 708 6 Membranes 105 35 Transport in Plants 726 7 Cell Communication and Multicellularity 125 36 Plant 740 37 Regulation of Plant Growth 756 PART THREE CELLS AND „ 38 in Flowering Plants 778 8 Energy, , and 144 39 Plant Responses to Environmental Challenges 797 9 Pathways that 165 10 : Energy from 185 PART NINE „ ANIMALS: FORM AND FUNCTION PART FOUR „ AND 40 , , and 11 The and Cell 205 Regulation 815 12 Inheritance, Genes, and 232 41 Animal 834 13 DNA and Its Role in Heredity 259 42 : Animal Defense 856 14 From DNA to : Expression 281 43 Animal Reproduction 880 15 Gene and Molecular 304 44 Animal Development 902 16 Regulation of 328 45 , , and Nervous Systems 924 PART FIVE „ 46 Sensory Systems 946 17 Genomes 352 47 The Mammalian Nervous 967 18 Recombinant DNA and 373 48 Musculoskeletal Systems 986 19 Differential Gene Expression in Development 392 49 Exchange 1005 20 Genes, Development, and Evolution 412 50 Circulatory Systems 1025 51 Nutrition, , and Absorption 1048 PART SIX „ THE PATTERNS AND PROCESSES 52 Salt and Balance and OF EVOLUTION 1071 21 Mechanisms of Evolution 427 53 Animal 1093 22 Reconstructing and Using Phylogenies 449 23 467 PART TEN „ 24 Evolution of Genes and Genomes 485 54 Ecology and the Distribution of Life 1121 25 The on 505 55 Ecology 1149 56 Interactions and 1169 PART SEVEN „ THE EVOLUTION OF DIVERSITY 57 Ecology 1188 26 , , and 525 58 and Global Ecology 1207 27 The Origin and Diversifi cation of 549 59 and 1228 28 Plants without : From Water to 569

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PART ONE The Science of Life and Its Chemical Basis 1 Studying Life 1

1.1 What Is Biology? 2 Life arose from non-life via chemical evolution 3 Cellular evolved in the common ancestor of life 3 Photosynthesis allows some to capture energy from the 4 Biological is contained in a genetic language common Biology is the basis of medical Hydrophobic interactions bring to all organisms 5 practice 15 together nonpolar of all living organisms Biology can inform public policy 16 molecules 30 evolve 6 Biology is crucial for understanding van der Waals forces involve can trace the ecosystems 17 contacts between 30 evolutionary tree of life 6 Biology helps us understand and 2.3 How Do Atoms Change Cellular specialization and appreciate biodiversity 17 Partners in Chemical differentiation underlie Reactions? 31 multicellular life 9 Small Molecules Living organisms interact with one 2.4 What Makes Water So another 9 2 and the Chemistry Important for Life? 32 supply energy and are Water has a unique structure and the basis of 10 of Life 21 special properties 32 Living organisms must regulate The reactions of life take place in their 10 2.1 How Does Atomic Structure aqueous 33 Explain the Properties of 1.2 How Do Biologists Aqueous solutions may be acidic or ? 22 Investigate Life? 11 basic 34 An element consists of only one Observing and quantifying are kind of 22 important skills 11 Proteins, Each element has a unique number Scientific methods combine of 22 , experimentation, 3 Carbohydrates, and logic 11 The number of differs among isotopes 22 and Lipids 39 have the potential to falsify The behavior of hypotheses 12 determines chemical bonding 3.1 What Kinds of Molecules and geometry 24 Characterize Living Statistical methods are essential scientific tools 13 2.2 How Do Atoms Bond to Things? 40 Discoveries in biology can be Form Molecules? 26 Functional groups give specific generalized 14 properties to biological Covalent bonds consist of shared molecules 40 Not all forms of inquiry are pairs of electrons 26 scientific 14 Isomers have different Ionic attractions form by electrical arrangements of the same 1.3 Why Does Biology Matter? attraction 28 atoms 41 15 bonds may form within The of or between molecules with polar reflect their functions 41 Modern depends on covalent bonds 30 biology 15

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Most macromolecules are formed are simple DNA carries information and is by condensation and broken 52 expressed through RNA 65 down by 42 Glycosidic linkages bond The DNA base sequence reveals 3.2 What Are the Chemical monosaccharides 53 evolutionary relationships 66 Structures and Functions of store energy and have other important Proteins? 42 provide structural materials 53 roles 66 Chemically modified carbohydrates 4.2 How and Where Did the Amino acids are the building blocks contain additional functional of proteins 43 groups 55 Small Molecules of Life linkages form the Originate? 67 backbone of a protein 43 3.4 What Are the Chemical Experiments disproved the The primary structure of a protein Structures and Functions of spontaneous of is its amino sequence 45 Lipids? 56 life 67 The secondary structure of a and oils are triglycerides 56 Life began in water 68 protein requires hydrogen form biological Life may have come from outside bonding 45 membranes 57 Earth 69 The tertiary structure of a protein is Some lipids have roles in energy Prebiotic synthesis experiments formed by bending and conversion, regulation, and model early Earth 69 folding 46 protection 57 The quaternary structure of a 4.3 How Did the Large protein consists of subunits 48 Molecules of Life Shape and surface chemistry Nucleic Acids Originate? 71 contribute to protein and the Origin of Chemical evolution may have led to function 48 4 polymerization 71 Environmental conditions affect Life 62 RNA may have been the first protein structure 50 biological catalyst 71 Protein shapes can change 50 4.1 What Are the Chemical Structures and Functions of 4.4 How Did the First Cells Molecular chaperones help shape Originate? 71 proteins 51 Nucleic Acids? 63 Experiments explore the origin of Nucleotides are the building blocks 3.3 What Are the Chemical cells 73 of nucleic acids 63 Structures and Functions of Some ancient cells left a Base pairing occurs in both DNA Carbohydrates? 51 imprint 74 and RNA 63

PART TWO Cells Cells: The Working can be studied by The extracellular supports or isolated for functions in animals 100 5 chemical analysis 84 Units of Life 77 5.5 How Did Eukaryotic Cells are factories for protein Originate? 101 5.1 What Features Make Cells synthesis 84 the Fundamental Units of The nucleus contains most of the Internal membranes and the generic information 85 nuclear envelope probably came Life? 78 from the plasma The is a Cell size is limited by the surface membrane 101 area-to-volume ratio 78 group of interrelated organelles 88 Some organelles arose by reveal the features of endosymbiosis 102 cells 79 Some organelles transform energy 91 The plasma membrane forms the outer surface of every cell 79 There are several other membrane-enclosed Cells are classified as either organelles 93 prokaryotic or eukaryotic 81 The is important in 5.2 What Features Characterize cell structure and Prokaryotic Cells? 82 movement 94 Prokaryotic cells share certain Biologists can manipulate living features 82 systems to establish cause and effect 98 Specialized features are found in some 83 5.4 What Are the Roles of 5.3 What Features Characterize Extracellular Eukaryotic Cells? 84 Structures? 99 Compartmentalization is the key to The plant is an eukaryotic cell function 84 extracellular structure 99 © Sinauer Associates, Inc. This material cannot be copied, reproduced, manufactured or disseminated in any form without express written permission from the publisher. Contents XXIII

Cell A pathway involves a signal, a , and 6 Membranes 105 responses 126

6.1 What Is the Structure of a 7.2 How Do Signal Receptors Biological Membrane? 106 Initiate a Cellular Response? 127 Lipids form the hydrophobic core of the membrane 106 Receptors that recognize chemical signals have specific binding Membrane proteins are sites 127 asymmetrically distributed 107 Receptors can be classified by Membranes are constantly location and function 128 changing 109 Intracellular receptors are located Plasma membrane carbohydrates in the or the are recognition sites 109 nucleus 130 6.2 How Is the Plasma 7.3 How Is the Response to a Membrane Involved in Cell Signal Transduced through Adhesion and the Cell? 131 Recognition? 110 A cascade amplifies Cell recognition and adhesion a response to involve proteins and binding 131 carbohydrates at the cell Second messengers can amplify surface 111 Different energy sources distinguish different active transport signals between receptors and Three types of cell junctions target molecules 132 connect adjacent cells 111 systems 118 Signal transduction is highly Cell membranes adhere to the 6.5 How Do Large Molecules regulated 136 111 Enter and Leave a Cell? 120 7.4 How Do Cells Change in 6.3 What Are the Passive Response to Signals? 137 Processes of Membrane Macromolecules and enter the cell by endocytosis 120 channels open in response to Transport? 113 signals 137 is the process of random Receptor-mediated endocytosis is highly specific 121 activities change in movement toward a state of response to signals 138 equilibrium 113 Exocytosis moves materials out of the cell 122 Signals can initiate DNA Simple diffusion takes place 139 through the bilayer 114 Cell Communication 7.5 How Do Cells in a is the diffusion of water Multicellular across membranes 114 7 and Multicellularity Communicate Diffusion may be aided by channel 125 Directly? 139 proteins 115 Animal cells communicate through Carrier proteins aid diffusion by 7.1 What Are Signals, and How gap junctions 139 binding substances 117 Do Cells Respond to Plant cells communicate through 6.4 What are the Active Them? 126 plasmodesmata 140 Processes of Membrane Cells receive signals from the Modern organisms provide clues Transport? 118 physical environment and from about the evolution of cell–cell other cells 126 interactions and Active transport is directional 118 multicellularity 140

PART THREE Cells and Energy Energy, Enzymes, There are two basic types of Chemical reactions release or energy 145 consume energy 147 8 and Metabolism There are two basic types of Chemical equilibrium and free 144 metabolism 145 energy are related 148 The first law of : 8.2 What Is the Role of ATP Energy is neither created nor 8.1 What Physical Principles destroyed 146 in Biochemical Underlie Biological Energy The second law of Energetics? 149 Transformations? 145 thermodynamics: Disorder tends ATP hydrolysis releases to increase 146 energy 149

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ATP couples exergonic and 9.2 What Are the Aerobic 10.2 How Does Photosynthesis endergonic reactions 150 Pathways of Convert Light Energy into ? 169 Chemical Energy? 188 8.3 What Are Enzymes? 151 In , glucose is partially Light energy is absorbed by To speed up a reaction, an energy oxidized and some energy is and other barrier must be overcome 151 released 169 188 Enzymes bind specific reactants at Pyruvate oxidation links glycolysis Light absorption results in their active sites 152 and the 170 photochemical change 190 Enzymes lower the energy barrier The citric acid cycle completes Reduction leads to ATP and but do not affect the oxidation of glucose to NADPH formation 191 equilibrium 153 CO2 170 is the source of 8.4 How Do Enzymes Pyruvate oxidation and the citric the ATP produced in ? 154 acid cycle are regulated by the photophosphorylation 192 Enzymes can orient concentrations of starting materials 171 10.3 How Is Chemical Energy substrates 154 Used to Synthesize Enzymes can induce in the 9.3 How Does Oxidative Carbohydrates? 193 154 Form Radioisotope labeling Enzymes can temporarily add ATP? 171 experiments revealed the steps chemical groups to The respiratory chain transfers of the 193 substrates 154 electrons and protons, and The Calvin cycle is made up of Molecular structure determines releases energy 172 three processes 194 enzyme function 155 diffusion is coupled to ATP Light stimulates the Calvin Some enzymes require other synthesis 173 cycle 196 molecules in to Some use non-O2 function 155 acceptors 176 10.4 How Have Plants Adapted The substrate concentration affects Photosynthesis to the reaction rate 156 9.4 How Is Energy Harvested Environmental from Glucose in the Absence Conditions? 197 8.5 How Are Enzyme Activities of ? 177 Regulated? 156 Rubisco catalyzes the reaction of yields RuBP with O2 or CO2 197 Enzymes can be regulated by much more energy than inhibitors 157 C3 plants undergo 178 photorespiration but C plants Allosteric enzymes are controlled 4 The yield of ATP is reduced by the do not 198 via changes in shape 159 impermeability of mitochondria CAM plants also use PEP Allosteric effects regulate many to NADH 178 carboxylase 200 metabolic pathways 160 Many enzymes are regulated 9.5 How Are Metabolic 10.5 How Does Photosynthesis through reversible Pathways Interrelated and Interact with Other phosphorylation 161 Regulated? 179 Pathways? 200 Enzymes are affected by their Catabolism and are environment 161 linked 179 Catabolism and anabolism are Pathways That integrated 180 Metabolic pathways are regulated 9 Harvest Chemical systems 181 Energy 165 Photosynthesis: 9.1 How Does Glucose Energy from Oxidation Release Chemical 10 Energy? 166 Sunlight 185 Cells trap free energy while metabolizing glucose 166 10.1 What Is Photosynthesis reactions transfer electrons 186 and energy 167 Experiments with isotopes + The coenzyme NAD is a key show that O2 comes from H2O electron carrier in redox in oxygenic reactions 167 photosynthesis 186 An overview: Harvesting energy Photosynthesis involves two from glucose 168 pathways 188

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PART FOUR Genes and Heredity The Cell Cycle and The number, shapes, and sizes of the metaphase chromosomes 11 205 constitute the karyotype 224 Polyploids have more than two 11.1 How Do Prokaryotic and complete sets of chromosomes Eukaryotic Cells 224 Divide? 206 11.6 In a Living Organism, Prokaryotes divide by binary How Do Cells Die? 225 206 Eukaryotic cells divide by 11.7 How Does Unregulated or followed by Cell Division Lead to 207 Cancer? 227 11.2 How Is Eukaryotic Cell Cancer cells differ from normal cells 227 Division Controlled? 208 Cancer cells lose control over the Specific internal signals trigger cell cycle and 228 events in the cell cycle 208 Cancer treatments target the factors can stimulate cells cycle 228 to divide 211 12.3 How Do Genes Interact? 244 11.3 What Happens during Inheritance, Genes, Mitosis? 211 vigor results from new and Chromosomes gene combinations and Prior to mitosis, eukaryotic DNA 12 interactions 244 is packed into very compact 232 The environment affects gene chromosomes 211 action 245 Overview: Mitosis segregates 12.1 What Are the Mendelian Most complex are copies of genetic determined by multiple genes information 212 Laws of Inheritance? 233 and the environment 246 The centrosomes determine the Mendel used the scientific of cell division 212 method to his 12.4 What Is the Relationship hypotheses 233 The spindle begins to form between Genes and during prophase 213 Mendel’s first experiments Chromosomes? 247 involved monohybrid separation and crosses 234 Genes on the same chromosome movement are highly are linked 247 organized 214 Mendel’s first law states that the two copies of a gene Genes can be exchanged Cytokinesis is the division of the segregate 236 between chromatids and cytoplasm 216 mapped 247 Mendel verified his hypotheses 11.4 What Role Does Cell by performing test Linkage is revealed by studies of Division Play in a Sexual crosses 237 the chromosomes 249 Life Cycle? 217 Mendel’s second law states that 12.5 What Are the Effects of by mitosis copies of different genes assort Genes Outside the results in genetic independently 237 Nucleus? 252 constancy 217 Probability can be used to predict by meiosis inheritance 239 12.6 How Do Prokaryotes results in genetic Mendel’s laws can be observed in Transmit Genes? 253 diversity 218 pedigrees 240 Bacteria exchange genes by conjugation 253 11.5 What Happens during 12.2 How Do Interact? 241 Bacterial conjugation is controlled Meiosis? 219 by 254 Meiotic division reduces the New alleles arise by chromosome number 219 mutation 241 Chromatid exchanges during Many genes have multiple DNA and Its Role meiosis I generate genetic alleles 242 13 in Heredity 259 diversity 219 is not always complete 242 During meiosis homologous 13.1 What Is the Evidence that chromosomes separate by In codominance, both alleles at a independent assortment 220 locus are expressed 243 the Gene Is DNA? 260 Meiotic lead to abnormal Some alleles have multiple DNA from one type of bacterium chromosome structures and phenotypic effects 243 genetically transforms another numbers 222 type 260

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Viral infection experiments One gene determines one Gene Mutation confirmed that DNA is the polypeptide 283 genetic material 261 and Molecular 14.2 How Does Information 15 Eukaryotic cells can also be Medicine 304 genetically transformed by Flow from Genes to DNA 263 Proteins? 284 Three types of RNA have roles in 15.1 What Are ? 305 13.2 What Is the Structure of the information flow from DNA Mutations have different DNA? 264 to protein 285 phenotypic effects 305 Watson and Crick used modeling In some cases, RNA determines Point mutations are changes in to deduce the structure of the sequence of DNA 285 single nucleotides 306 DNA 264 Chromosomal mutations are Four key features define DNA 14.3 How Is the Information extensive changes in the structure 265 Content in DNA genetic material 307 The double-helical structure of Transcribed to Produce and transposons can DNA is essential to its RNA? 286 cause loss of function function 266 RNA polymerases share common mutations or duplications 308 13.3 How Is DNA features 286 Mutations can be spontaneous or Replicated? 267 Transcription occurs in three induced 308 steps 286 Mutagens can be natural or Three modes of DNA replication The information for protein artificial 310 appeared possible 267 synthesis in the genetic Some base pairs are more An elegant 288 vulnerable than others to demonstrated that mutation 310 DNA replication is 14.4 How Is Eukaryotic DNA Mutations have both benefits and semiconservative 268 Transcribed and the RNA costs 310 There are two steps in Processed? 290 DNA replication 268 Many eukaryotic genes are 15.2 What Kinds of Mutations DNA polymerases add interrupted by noncoding Lead to Genetic ? nucleotides to the growing sequences 290 311 chain 269 Eukaryotic gene transcripts are Genetic mutations may make Many other proteins assist with processed before proteins dysfunctional 311 DNA polymerization 272 291 -causing mutations may The two DNA strands grow involve any number of base differently at the replication 14.5 How Is RNA Translated into Proteins? 293 pairs 312 fork 272 Expanding triplet repeats are not fully replicated Transfer carry specific demonstrate the fragility of and are prone to repair 275 amino acids and bind to some human genes 313 specific codons 293 13.4 How Are Errors in DNA Cancer often involves somatic Each tRNA is specifically attached mutations 314 Repaired? 276 to an 294 13.5 How Does the Polymerase The is the workbench Chain Reaction Amplify for translation 294 DNA? 277 Translation takes place in three steps 295 The polymerase chain reaction Polysome formation increases the makes multiple copies of DNA rate of protein synthesis 297 sequences 277 14.6 What Happens to Polypeptides after From DNA to Translation? 298 14 Protein: Gene Signal sequences in proteins direct them to their cellular Expression 281 destinations 298 Many proteins are modified after 14.1 What Is the Evidence that translation 300 Genes Code for Proteins? 282 in led to the proposal that genes determine enzymes 282 Experiments on bread established that genes determine enzymes 282

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Most diseases are caused by Regulation of Gene Many undergo a multiple genes and lytic cycle 339 environment 314 16 Expression 328 Some bacteriophages can undergo 15.3 How Are Mutations a lysogenic cycle 340 16.1 How Is Gene Expression Eukaryotic viruses can have Detected and Analyzed? Regulated in 315 complex life cycles 341 Prokaryotes? 329 HIV gene regulation occurs at the Restriction enzymes cleave DNA Regulating gene transcription level of transcription at specific sequences 315 conserves energy 329 elongation 341 Gel electrophoresis separates are units of DNA fragments 316 16.4 How Do Epigenetic transcriptional regulation in Changes Regulate Gene DNA fingerprinting combines prokaryotes 330 PCR with restriction analysis Expression? 343 Operator– interactions and electrophoresis 317 control transcription in the lac DNA occurs at Reverse can be used to and trp operons 330 promoters and silences identify mutations that lead to transcription 343 Protein synthesis can be disease 318 controlled by increasing protein modifications affect Genetic markers can be used to efficiency 332 transcription 344 find disease-causing RNA polymerases can be directed Epigenetic changes can be induced genes 318 to particular classes of by the environment 344 The DNA barcode project aims to promoters 332 DNA methylation can result in identify all organisms on 344 Earth 319 16.2 How Is Eukaryotic Gene Global chromosome changes Transcription Regulated? 15.4 How Is Genetic Screening involve DNA methylation 345 333 Used to Detect 16.5 How Is Eukaryotic Gene Diseases? 320 General transcription factors act at eukaryotic promoters 333 Expression Regulated after Screening for disease phenotypes Specific proteins can recognize Transcription? 346 involves analysis of proteins and bind to DNA sequences Different mRNAs can be made and other chemicals 320 and regulate transcription from the same gene by DNA testing is the most accurate 335 346 way to detect abnormal Specific protein–DNA interactions Small RNAs are important genes 320 underlie binding 335 regulators of gene -specific oligonucleotide The expression of transcription expression 347 hybridization can detect factors underlies cell Translation of mRNA can be mutations 321 differentiation 336 regulated by proteins and 15.5 How Are Genetic Diseases The expression of sets of genes riboswitches 348 Treated? 322 can be coordinately regulated Genetic diseases can be treated by transcription factors 336 by modifying the 16.3 How Do Viruses Regulate 322 Their Gene offers the hope of Expression? 339 specific treatments 323

PART FIVE Genomes

17.2 What Have We Learned 17 Genomes 352 from Sequencing Prokaryotic Genomes? 356 17.1 How Are Genomes Prokaryotic genomes are Sequenced? 353 compact 356 New methods have been The sequencing of prokaryotic developed to rapidly sequence and viral genomes has many DNA 353 potential benefits 357 sequences yield several Metagenomics allows us to kinds of information 355 describe new organisms and ecosystems 357 Some sequences of DNA can move about the genome 358

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Will defining the genes required 18.4 What Other Tools Are Used Differential gene transcription is a for cellular life lead to artificial to Study DNA hallmark of cell life? 359 Function? 380 differentiation 398 17.3 What Have We Learned Genes can be expressed in 19.4 How Does Gene from Sequencing different biological Expression Determine Eukaryotic Genomes? 361 systems 380 ? 399 DNA mutations can be created in Model organisms reveal many the 381 Multiple proteins interact to characteristics of eukaryotic determine developmental genomes 361 Genes can be inactivated by programmed cell 399 homologous Eukaryotes have gene recombination 381 Plants have identity 363 genes 400 Complementary RNA can prevent Eukaryotic genomes contain the expression of specific gradients provide many repetitive genes 382 positional information 401 sequences 364 DNA microarrays reveal RNA A cascade of transcription factors 17.4 What Are the expression patterns 382 establishes body segmentation in the 401 Characteristics of the 18.5 What Is Biotechnology? ? 366 383 19.5 Is Cell Differentiation Reversible? 405 The human genome sequence Expression vectors can turn cells held some surprises 366 into protein factories 384 Plant cells can be totipotent 405 Comparative reveals Nuclear transfer allows the the evolution of the human 18.6 How Is Biotechnology cloning of animals 406 genome 366 Changing Medicine and Multipotent stem cells Human genomics has potential Agriculture? 384 differentiate in response to benefits in medicine 367 Medically useful proteins can be environmental signals 408 17.5 What Do the New made using Pluripotent stem cells can be Disciplines of biotechnology 384 obtained in two ways 408 and Metabolomics DNA manipulation is changing agriculture 386 Reveal? 369 Genes, There is public concern about The is more complex biotechnology 388 Development, and than the genome 369 20 Metabolomics is the study of Evolution 412 chemical phenotype 370 Differential Gene Expression in 20.1 How Can Small Genetic 19 Changes Result in Large Recombinant DNA Development 392 Changes in Phenotype? 18 and Biotechnology 413 373 19.1 What Are the Processes of Developmental genes in distantly Development? 393 related organisms are similar 413 18.1 What Is Recombinant Development involves distinct but overlapping processes 393 DNA? 374 Cell fates become progressively 18.2 How Are New Genes more restricted during Inserted into Cells? 375 development 394 Genes can be inserted into 19.2 How Is Cell Fate prokaryotic or eukaryotic Determined? 395 cells 376 Cytoplasmic segregation can A variety of methods are used to determine polarity and cell fate insert recombinant DNA into 395 cells 376 Inducers passing from one cell to Reporter genes help select or another can determine cell identify host cells containing fates 395 recombinant DNA 377 19.3 What Is the Role of Gene 18.3 What Sources of DNA Are Expression in Used in Cloning? 379 Development? 397 Libraries provide collections of involves DNA fragments 379 signal transduction pathways cDNA is made from mRNA that lead to differential gene transcripts 379 expression 397 Synthetic DNA can be made by PCR or by organic chemistry 380 © Sinauer Associates, Inc. This material cannot be copied, reproduced, manufactured or disseminated in any form without express written permission from the publisher. Contents XXIX

20.2 How Can Mutations with Differences in Hox gene Dietary information can be a Large Effects Change Only expression patterns result in predictor of future One Part of the Body? 415 major differences in body conditions 421 Genetic switches govern how the plans 418 A variety of environmental signals genetic toolkit is used 415 Mutations in developmental influence development 421 allows for differences genes can produce major morphological changes 418 20.5 How Do Developmental in the patterns of gene Genes Constrain expression 416 20.4 How Can the Environment Evolution? 423 20.3 How Can Developmental Modulate Development? Evolution usually proceeds by Changes Result in 420 changing what’s already Differences among Temperature can determine there 423 Species? 418 sex 420 Conserved developmental genes can lead to 423

PART SIX The Patterns and Processes of Evolution Mechanisms of Deviations from Hardy– Weinberg equilibrium 21 Evolution 427 show that evolution is occurring 438 21.1 What Is the Relationship acts between Fact and directly on in Evolution? 428 phenotypes 438 Natural selection can Darwin and Wallace introduced the change or stabilize idea of evolution by natural populations 439 selection 428 Evolutionary theory has continued 21.4 How Is Genetic to develop over the past Variation century 430 Distributed and contributes to Maintained within phenotypic variation 431 Populations? 441 Reconstructing and 21.2 What Are the Mechanisms Neutral mutations accumulate in Using Phylogenies of Evolutionary populations 441 22 Change? 432 Sexual recombination amplifies 449 the number of possible Mutation generates genetic 441 variation 432 22.1 What Is Phylogeny? 450 Frequency-dependent selection Selection acting on genetic All of life is connected through maintains genetic variation variation leads to new evolutionary history 451 within populations 441 phenotypes 432 Comparisons among species Heterozygote advantage may change allele require an evolutionary maintains polymorphic frequencies 433 perspective 451 loci 442 may cause large Genetic variation within species is 22.2 How Are Phylogenetic changes in small maintained in geographically Trees Constructed? 452 populations 434 distinct populations 443 Nonrandom can change Parsimony provides the simplest or allele 21.5 What Are the Constraints explanation for phylogenetic data 454 frequencies 434 on Evolution? 444 Phylogenies are reconstructed 21.3 How Do Biologists Developmental processes from many sources of Measure Evolutionary constrain evolution 444 data 454 Change? 436 Trade-offs constrain Mathematical models expand the evolution 445 Evolutionary change can be power of phylogenetic measured by allele and Short-term and long-term reconstruction 456 genotype frequencies 436 evolutionary outcomes The accuracy of phylogenetic sometimes differ 446 Evolution will occur unless certain methods can be tested 457 restrictive conditions exist 437

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22.3 How Do Biologists Use Postzygotic isolating mechanisms evolution is used to Phylogenetic Trees? 458 result in selection against produce new molecules 500 Phylogenetic trees can be used to hybridization 478 is used to reconstruct past events 458 Hybrid zones may form if study and combat Phylogenies allow us to compare is diseases 501 and contrast living incomplete 478 organisms 459 23.5 Why Do Rates of The History of Life Phylogenies can reveal Speciation Vary? 480 459 25 on Earth 505 Several ecological and behavioral Ancestral states can be factors influence speciation reconstructed 460 rates 480 25.1 How Do Date Molecular clocks help date Rapid speciation can lead to Ancient Events? 506 evolutionary events 461 adaptive 481 Radioisotopes provide a way to 22.4 How Does Phylogeny date and rocks 507 Relate to Evolution of Genes Radiometric methods have Classification? 462 been expanded and 24 refined 507 Evolutionary history is the basis and Genomes 485 Scientists have used several for modern biological methods to construct a classification 463 24.1 How Are Genomes Used to geological 508 Several of biological Study Evolution? 486 nomenclature govern the use Evolution of genomes results in of scientific 463 biological diversity 486 25.2 How Have Earth’s Genes and proteins are Continents and compared through sequence Changed over Time? 508 23 Speciation 467 alignment 486 The continents have not always Models of sequence evolution are been where they are used to calculate evolutionary today 509 23.1 What Are Species? 468 divergence 487 Earth’s has shifted We can recognize many species Experimental studies examine between hot and cold by their appearance 468 molecular evolution conditions 510 Reproductive isolation is directly 489 Volcanoes have occasionally key 468 24.2 What Do Genomes Reveal changed the history of The approach takes a life 510 long-term view 469 about Evolutionary Processes? 491 Extraterrestrial events have The different species concepts triggered changes on are not mutually Much of evolution is neutral 492 Earth 511 exclusive 469 Positive and purifying selection Oxygen concentrations in Earth’s can be detected in the 23.2 What Is the Genetic Basis have changed genome 492 over time 511 of Speciation? 470 Genome size also evolves 494 Incompatibilities between genes 25.3 What Are the Major Events can produce reproductive 24.3 How Do Genomes Gain in Life’s History? 514 isolation 470 and Maintain Functions? Several processes contribute to Reproductive isolation develops 496 the paucity of fossils 514 with increasing genetic Lateral gene transfer can result in Precambrian life was small and divergence 470 the gain of new functions 496 aquatic 515 23.3 What Barriers to Gene Most new functions arise Life expanded rapidly during the Flow Result in following gene 516 duplication 496 Speciation? 472 Many groups of organisms that Some gene families evolve arose during the Cambrian Physical barriers give rise to through concerted later diversified 516 472 evolution 498 Geographic differentiation occurs increased during the Mesozoic without physical barriers 473 24.4 What Are Some Applications of Molecular era 521 23.4 What Happens When Evolution? 499 Modern biotas evolved during Newly Formed Species the Cenozoic era 521 Molecular sequence data are The tree of life is used to Come into Contact? 475 used to determine the reconstruct evolutionary Prezygotic isolating mechanisms evolutionary history of events 522 prevent hybridization 476 genes 499 Gene evolution is used to study protein function 500

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PART SEVEN The Evolution of Diversity Bacteria, Archaea, 26 and Viruses 525

26.1 Where Do Prokaryotes Fit into the Tree of Life? 526 The two prokaryotic domains differ in significant ways 526 The small size of prokaryotes has hindered our study of their evolutionary relationships 527 The sequences of prokaryotes reveal their evolutionary relationships 528 Lateral gene transfer can lead to discordant gene trees 529 Prokaryotes live on and in other Rhizaria typically have long, thin organisms 539 pseudopods 557 The great majority of species have never been are critical to human Excavates began to diversify studied 530 539 about 1.5 billion years A small minority of bacteria are ago 558 26.2 Why Are Prokaryotes So 541 Amoebozoans use lobe-shaped Diverse and Abundant? pseudopods for 530 26.4 How Do Viruses Relate to locomotion 559 Life’s Diversity and The low-GC Gram-positives Ecology? 543 27.3 What Is the Relationship include some of the smallest between Sex and cellular organisms 530 Many RNA viruses probably represent escaped genomic Reproduction in Some high-GC Gram-positives ? 562 are valuable sources of components of cellular antibiotics 532 life 544 Some protists reproduce without Hyperthermophilic bacteria live at Some DNA viruses may have sex and have sex without very high 532 evolved from reduced cellular reproduction 562 organisms 544 Hadobacteria live in extreme Some life cycles feature environments 532 genomes contain alternation of endogenous retroviruses 545 562 were the first photosynthesizers 532 Viruses can be used to fight 27.4 How Do Protists Affect bacterial infections 545 Spirochetes move by means of Their Environments? 563 axial filaments 533 Viruses are found throughout the 546 are primary Chlamydias are extremely small producers 563 parasites 533 Some microbial eukaryotes are The are a large The Origin and deadly 563 and diverse group 534 Some microbial eukaryotes are Gene sequencing enabled 27 Diversifi cation of 564 biologists to differentiate the Eukaryotes 549 We rely on the remains of ancient Archaea 534 marine protists 565 Most crenarchaeotes live in hot or 27.1 How Did the Eukaryotic acidic places 536 Cell Arise? 550 Euryarchaeotes are found in Plants without The modern eukaryotic cell arose surprising places 536 in several steps 550 Seeds: From Water Korarchaeotes and 28 have been nanoarchaeotes are less well to Land 569 transferred among eukaryotes known 537 several 551 28.1 How Did Photosynthesis 26.3 How Do Prokaryotes Affect 27.2 What Features Account for Arise in Plants? 570 Their Environments? 537 Protist Diversity? 552 Several distinct of Prokaryotes have diverse Alveolates have sacs under their were among the first metabolic pathways 537 plasma membranes 553 photosynthetic Prokaryotes play important roles Stramenopiles typically have two eukaryotes 571 in element cycling 538 flagella of unequal length 555 Many prokaryotes form complex communities 539

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Two groups of algae are The Evolution the closest relatives of land plants 572 30 and Diversity of There are ten major groups of Fungi 608 land plants 573 28.2 When and How Did 30.1 What Is a ? 609 Plants Colonize Unicellular absorb nutrients Land? 574 directly 609 to life on land Multicellular fungi use hyphae to distinguish land plants from absorb nutrients 609 green algae 574 Fungi are in intimate contact with Life cycles of land plants feature their environment 610 alternation of generations 574 30.2 How Do Fungi Interact with Other Nonvascular land plants live where water is readily Organisms? 611 available 575 Saprobic fungi are critical to the The of nonvascular planetary cycle 611 land plants are dependent on Some fungi engage in parasitic or the gametophytes 575 predatory interactions 611 Liverworts are the sister Mutualistic fungi engage in of the remaining land relationships that benefit both plants 577 partners 612 A change in stem Water and transport Endophytic fungi protect some enabled seed plants to grow to mechanisms emerged in the plants from pathogens, great heights 591 577 , and 615 have distinctive 29.2 What Are the Major 30.3 How Do Major Groups of chloroplasts and stalkless Groups of sporophytes 578 Fungi Differ in Structure ? 592 and Life History? 615 There are four major groups of 28.3 What Features Allowed Fungi reproduce both sexually living gymnosperms 592 Land Plants to Diversify in and asexually 616 have cones and no Form? 579 Microsporidia are highly reduced, swimming 593 Vascular tissues transport water parasitic fungi 617 and dissolved materials 579 29.3 How Do and Most chytrids are aquatic 617 Vascular plants allowed Increase the Reproductive Some fungal life cycles feature herbivores to colonize the Success of separate fusion of land 580 Angiosperms? 596 and nuclei 619 The closest relatives of vascular Angiosperms have many shared Arbuscular mycorrhizal fungi form plants lacked 580 derived traits 596 symbioses with plants 619 The are sister to the The sexual structures of The dikaryotic condition is a other vascular plants 581 angiosperms are flowers 596 synapomorphy of sac fungi and Horsetails and constitute a club fungi 620 structure has evolved over clade 581 time 597 The sexual reproductive structure The vascular plants branched of sac fungi is the ascus 620 Angiosperms have coevolved out 582 with animals 598 The sexual reproductive structure Heterospory appeared among of club fungi is the The angiosperm life cycle the vascular plants 584 basidium 622 produces diploid nourished by triploid 30.4 What Are Some The Evolution 600 Applications of Fungal Fruits aid angiosperm seed Biology? 623 of Seed Plants dispersal 601 29 Fungi are important in producing 588 Recent analyses have revealed and drink 623 the phylogenetic relationships Fungi record and help remediate of angiosperms 601 29.1 How Did Seed Plants environmental 624 Become Today’s Dominant 29.4 How Do Plants Benefit diversity and abundance Vegetation? 589 Human Society? 604 are indicators of air quality 624 Features of the seed plant life Seed plants have been sources of cycle protect and medicine since ancient Fungi are used as model 589 times 604 organisms in laboratory studies 624 The seed is a complex, well- Seed plants are our primary food protected package 591 source 605 Reforestation may depend on mycorrhizal fungi 626

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Fungi provide important weapons 31.4 How Do Life Cycles Differ 32.3 What Features Distinguish against diseases and among Animals? 639 the Major Groups of pests 626 Many animal life cycles feature Ecdysozoans? 665 specialized life stages 639 Several marine ecdysozoan Animal Origins Most animal life cycles have at groups have relatively few least one dispersal stage 640 species 665 31 and the Evolution Parasite life cycles facilitate and their relatives are dispersal and overcome host abundant and diverse 666 of Body Plans 629 defenses 640 32.4 Why Are So Some animals form colonies of 31.1 What Characteristics genetically identical, Diverse? 667 Distinguish the physiologically integrated relatives have fleshy, Animals? 630 640 unjointed 667 Animal is supported No life cycle can maximize all Jointed appendages appeared in by gene sequences and benefits 641 the trilobites 668 630 Chelicerates have pointed, 31.5 What Are the Major A few basic developmental nonchewing mouthparts 668 patterns differentiate major Groups of Animals? 643 Mandibles and antennae animal groups 633 are loosely organized characterize the remaining animals 643 arthropod groups 669 31.2 What Are the Features of Ctenophores are radially More than half of all described Animal Body Plans? 634 symmetrical and species are 671 Most animals are diploblastic 644 symmetrical 634 Placozoans are abundant but The structure of the body cavity rarely observed 645 Deuterostome influences movement 635 Cnidarians are specialized 33 Animals 678 Segmentation improves control of predators 645 movement 636 Some small groups of parasitic 33.1 What Is a Appendages have many animals may be the closest Deuterostome? 679 uses 636 relatives of bilaterians 648 Nervous systems coordinate Deuterostomes share early movement and allow sensory developmental patterns 679 processing 637 Protostome There are three major 32 Animals 651 deuterostome clades 679 31.3 How Do Animals Get Their Fossils shed light on Food? 637 deuterostome ancestors 679 32.1 What Is a Filter feeders capture small 33.2 What Features Distinguish prey 637 Protostome? 652 the , Herbivores eat plants 637 Cilia-bearing lophophores and trochophores evolved among the , and Their Predators and capture lophotrochozoans 652 and subdue prey 638 Relatives? 680 Ecdysozoans must shed their Parasites live in or on other Echinoderms have unique cuticles 654 organisms 638 structural features 680 Arrow worms retain some ancestral live on the remains of Hemichordates are wormlike developmental features 655 other organisms 639 marine deuterostomes 682 32.2 What Features Distinguish 33.3 What New Features the Major Groups of Evolved in the Lophotrochozoans? 656 ? 683 Most bryozoans and entoprocts of most lancelets and live in colonies 656 are sedentary 684 , , and A dorsal supporting structure gastrotrichs are structurally replaces the in diverse relatives 656 684 Ribbon worms have a long, The phylogenetic relationships of protrusible feeding organ 658 jawless are and use uncertain 685 lophophores to extract food Jaws and teeth improved feeding from the water 658 efficiency 686 have segmented Fins and swim bladders improved bodies 659 stability and control over Mollusks have undergone a locomotion 686 dramatic 662 33.4 How Did Vertebrates Colonize the Land? 689

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Jointed limbs enhanced support Crocodilians and share their Two major lineages of and locomotion on land 689 ancestry with the split late in the usually require moist 693 701 environments 690 Feathers allowed birds to Bipedal locomotion evolved in Amniotes colonized dry fly 695 human ancestors 702 environments 692 radiated after the Human became larger as adapted to life in many of non-avian jaws became smaller 704 693 dinosaurs 696 Humans developed complex 33.5 What Traits Characterize language and culture 705 the Primates? 701

PART EIGHT Flowering Plants: Form and Function The Plant Body The stem supports and Plants can control their total 34 flowers 720 numbers of stomata 734 708 Leaves are determinate organs 35.4 How Are Substances produced by apical Translocated in the 34.1 What Is the Basic Body 720 ? 734 Plan of Plants? 709 Many eudicot stems and roots undergo secondary and other solutes are Most angiosperms are either carried in the phloem 734 monocots or 709 growth 721 The pressure flow model appears Plants develop differently than 34.4 How Has Domestication to account for translocation in animals 710 Altered Plant Form? 723 the phloem 735 Apical–basal polarity and radial are characteristics of the plant body 711 Transport in 36 Plant 34.2 What Are the Major Tissues 35 Plants 726 Nutrition 740 of Plants? 712 The plant body is constructed 35.1 How Do Plants Take Up 36.1 What Nutrients Do Plants from three tissue systems 712 Water and Solutes? 727 Require? 741 Cells of the transport water All plants require specific and dissolved 714 differences govern the direction of water macronutrients and Cells of the phloem transport movement 727 micronutrients 741 the products of Deficiency symptoms reveal photosynthesis 714 Water and move across the cell plasma inadequate nutrition 742 34.3 How Do Meristems Build a membrane 728 Hydroponic experiments Continuously Growing Water and ions pass to the xylem identified essential elements 742 Plant? 715 by way of the and 729 Plants increase in size through primary and secondary 35.2 How Are Water growth 715 and Minerals A hierarchy of meristems Transported in generates the plant body 715 the Xylem? 730 Indeterminate primary growth The – originates in apical cohesion–tension meristems 715 accounts for The root apical gives xylem transport 731 rise to the root cap and the root primary meristems 716 35.3 How Do Stomata The products of the root’s Control the Loss primary meristems become of Water and root tissues 716 the Uptake of The root system anchors the CO2? 732 plant and takes up water and The guard cells dissolved minerals 718 control the size of The products of the stem’s the stomatal opening primary meristems become 733 stem tissues 719

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36.2 How Do Plants Acquire 37.2 What Do Nutrients? 743 Gibberellins and Plants rely on growth to find Do? 760 nutrients 743 Gibberellins have many uptake and assimilation effects on plant are regulated 744 growth and development 760 36.3 How Does Structure Auxin plays a role in Affect Plants? 744 differential plant are complex in growth 762 structure 745 Auxin affects plant Soils form through the growth in several weathering of 745 ways 765 Soils are the source of plant At the molecular level, nutrition 746 auxin and gibberellins can be used to add act similarly 767 nutrients to soil 746 37.3 What Are 36.4 How Do Fungi and Bacteria the Effects of Increase Nutrient Uptake Cytokinins, , Many flowering plants control by Plant Roots? 747 and Brassinosteroids? 768 or pollen tube growth to prevent Plants send signals for Cytokinins are active from seed inbreeding 782 colonization 747 to 768 Angiosperms perform double Mycorrhizae expand the root Ethylene is a gaseous fertilization 783 system 748 that hastens senescence Embryos develop within seeds and fruit 769 Soil bacteria are essential in contained in fruits 784 getting nitrogen from air to Brassinosteroids are plant Seed development is under plant cells 749 hormones 771 hormonal control 785 Nitrogenase catalyzes nitrogen 37.4 How Do Photoreceptors fixation 749 38.2 What Determines the Participate in Plant Growth Biological nitrogen fixation does Transition from the not always meet agricultural Regulation? 771 Vegetative to the needs 750 , cryptochromes, and Flowering State? 785 Plants and bacteria participate in zeaxanthin are blue-light receptors 771 Shoot apical meristems can the global 750 become inflorescence mediate the meristems 785 36.5 How Do Carnivorous and effects of red and far-red Parasitic Plants Obtain a light 772 A cascade of gene expression leads to flowering 786 Balanced Diet? 751 stimulates gene transcription 773 Photoperiodic cues can initiate Carnivorous plants supplement flowering 787 their nutrition 751 Circadian rhythms are entrained by light reception 774 Plants vary in their responses to Parasitic plants take advantage of photoperiodic cues 787 other plants 752 length is a key The plant–parasite relationship is Reproduction in photoperiodic cue that similar to plant–fungus and determines flowering 788 plant–bacteria Flowering Plants associations 753 38 The flowering originates 778 in a leaf 788 Florigen is a small protein 790 Regulation of 38.1 How Do Angiosperms Flowering can be induced by 37 Reproduce Sexually? 779 temperature or Plant Growth 756 gibberellin 790 The flower is an angiosperm’s 37.1 How Does Plant structure for sexual Some plants do not require an reproduction 779 environmental cue to Development flower 792 Proceed? 757 Flowering plants have microscopic 38.3 How Do Angiosperms In early development, the seed gametophytes 779 germinates and forms a Reproduce Asexually? 792 Pollination in the absence of growing 757 Many forms of asexual water is an evolutionary reproduction exist 792 Several hormones and 780 photoreceptors help regulate Vegetative reproduction has a A pollen tube delivers sperm cells plant growth 758 disadvantage 793 to the sac 780 Genetic screens have increased Vegetative reproduction is our understanding of plant important in agriculture 793 signal transduction 759

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Plant Responses 39.2 How Do Plants Deal with 39.3 How Do Plants Deal with Herbivores? 801 Environmental 39 to Environmental Mechanical defenses against Stresses? 806 Challenges 797 herbivores are Some plants have special widespread 801 adaptations to live in very dry 39.1 How Do Plants Deal with Plants produce constitutive conditions 806 Pathogens? 798 chemical defenses against Some plants grow in saturated herbivores 802 soils 808 Physical barriers form constitutive Some secondary metabolites play Plants can respond to drought defenses 798 multiple roles 803 stress 809 Plants can seal off infected parts Plants respond to herbivory with Plants can cope with temperature to limit damage 798 induced defenses 803 extremes 810 General and specific Jasmonates trigger a range of both involve multiple responses to wounding and 39.4 How Do Plants Deal with responses 799 herbivory 805 Salt and Heavy Specific immunity involves gene- Why don’t plants Metals? 810 for-gene resistance 800 themselves? 805 Most halophytes accumulate Specific immunity usually leads to Plants don’t always win the arms salt 811 the hypersensitive race 806 Some plants can tolerate heavy response 800 metals 811 Systemic acquired resistance is a form of long-term immunity 801

PART NINE Animals: Form and Function

Q is a measure of Physiology, 10 temperature Homeostasis, sensitivity 821 40 Animals acclimatize to and Temperature seasonal temperatures Regulation 815 821 40.4 How Do Animals 40.1 How Do Multicellular Alter Their Animals Supply the Needs Exchange with the of Their Cells? 816 Environment? 822 An internal environment makes Endotherms produce complex multicellular animals substantial amounts of possible 816 metabolic heat 822 Endotherms respond to cold by Physiological systems are and endotherms producing heat and adapt to regulated to maintain respond differently to changes cold by reducing heat homeostasis 816 in environmental loss 827 40.2 What Are the Relationships temperature 822 of water can between Cells, Tissues, and Energy budgets reflect dissipate heat, but at a Organs? 817 adaptations for regulating cost 829 body temperature 823 The mammalian thermostat uses Epithelial tissues are sheets of Both ectotherms and densely packed, tightly information 829 endotherms control Fever helps the body fight connected cells 817 flow to the 824 Muscle tissues generate force and infections 830 Some conserve metabolic Some animals conserve energy by movement 818 heat 825 Connective tissues include , turning down the Some ectotherms regulate thermostat 830 blood, and 818 metabolic heat Neural tissues include neurons production 825 and glial cells 819 Animal Hormones Organs consist of multiple 40.5 How Do Endotherms 41 tissues 820 Regulate Their Body 834 Temperatures? 826 40.3 How Does Temperature Basal metabolic rates correlate 41.1 What Are Hormones and Affect Living with body size 826 How Do They Work? 835 Systems? 820

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Endocrine signaling can act Immunology: Monoclonal have locally or at a distance 835 Animal Defense many uses 871 Hormones can be divided into 42 42.5 What Is the Cellular three chemical groups 836 Systems 856 ? 871 Hormone action is mediated by T cell receptors bind to antigens receptors on or within their 42.1 What Are the Major target cells 836 on cell surfaces 871 Defense Systems of Hormone action depends on the MHC proteins present antigen to of the target cell and its Animals? 857 T cells 872 receptors 837 Blood and lymph tissues play T-helper cells and MHC II proteins important roles in defense 857 contribute to the humoral 41.2 What Have Experiments White blood cells play many immune response 872 Revealed about Hormones defensive roles 858 Cytotoxic T cells and MHC I and Their Action? 838 proteins bind proteins contribute to the The first hormone discovered was pathogens or signal other cellular immune response 874 the gut hormone secretin 838 cells 858 Regulatory T cells suppress the humoral and cellular immune Early experiments on insects 42.2 What Are the illuminated hormonal signaling responses 874 systems 839 Characteristics of the MHC proteins are important in Three hormones regulate molting Innate Defenses? 859 tissue transplants 874 Barriers and local agents defend and maturation in 42.6 What Happens When the arthropods 840 the body against invaders 859 Immune System 41.3 How Do the Nervous and pathways stimulate Malfunctions? 875 Endocrine Systems the body’s defenses 860 Allergic reactions result from Interact? 842 Specialized proteins and cells hypersensitivity 875 The pituitary is an interface participate in innate Autoimmune diseases are caused between the nervous and immunity 860 by reactions against self endocrine systems 842 Inflammation is a coordinated antigens 876 The anterior pituitary is controlled response to infection or AIDS is an immune deficiency by hypothalamic injury 861 disorder 876 neurohormones 844 Inflammation can cause medical loops regulate problems 862 hormone secretion 844 Animal 42.3 How Does Adaptive 43 41.4 What Are the Major Immunity Develop? 862 Reproduction 880 Endocrine and Adaptive immunity has four key 43.1 How Do Animals Hormones? 845 features 862 Reproduce without The secretes Two types of adaptive immune thyroxine 845 responses interact: an Sex? 881 Three hormones regulate blood overview 863 and concentrations 847 Adaptive immunity develops as a produce new individuals by PTH lowers blood result of clonal selection 865 mitosis 881 levels 848 Clonal deletion helps the immune is the and glucagon regulate system distinguish self from development of unfertilized blood glucose nonself 865 881 concentrations 848 results in 43.2 How Do Animals The is two glands a secondary immune Reproduce Sexually? 882 in one 849 response 865 produces eggs Sex are produced by the are an application of and sperm 882 850 immunological memory 866 Fertilization is the union of sperm Melatonin is involved in biological 42.4 What Is the Humoral and 884 rhythms and Immune Response? 867 Getting eggs and sperm photoperiodicity 851 Some B cells develop into plasma together 887 Many chemicals may act as cells 867 Some individuals can function as hormones 851 Different antibodies share a both male and female 887 41.5 How Do We Study common structure 867 The evolution of vertebrate Mechanisms of Hormone There are five classes of reproductive systems parallels Action? 852 immunoglobulins 868 the move to land 888 Hormones can be detected and Immunoglobulin diversity results Animals with internal fertilization measured with from DNA rearrangements and are distinguished by where the immunoassays 852 other mutations 868 embryo develops 889 A hormone can act through many The constant region is involved in receptors 853 immunoglobulin switching 869 © Sinauer Associates, Inc. This material cannot be copied, reproduced, manufactured or disseminated in any form without express written permission from the publisher. XXXVIII Contents

43.3 How Do the Human Male 44.2 How Does Mitosis Divide Neurons, Glia, and and Female Reproductive Up the Early Embryo? 904 Systems Work? 889 repackages the 45 Nervous Systems Male sex organs produce and cytoplasm 904 924 deliver semen 889 Early cell divisions in mammals Male sexual function is controlled are unique 905 45.1 What Cells Are Unique to by hormones 892 Specific blastomeres generate the ? 925 Female sex organs produce eggs, specific tissues and The structure of neurons reflects receive sperm, and nurture the organs 906 their functions 925 embryo 892 Germ cells are a unique lineage Glia are the “silent partners” of The ovarian cycle produces a even in species with regulative neurons 926 mature egg 893 development 908 The uterine cycle prepares an 44.3 How Does 45.2 How Do Neurons Generate environment for a fertilized Generate Multiple Tissue and Transmit Electric egg 893 Layers? 908 Signals? 927 Hormones control and coordinate of the vegetal pole Simple electrical concepts the ovarian and uterine underlie neural function 927 cycles 894 characterizes gastrulation in the sea urchin 908 Membrane potentials can be FSH receptors determine which measured with follicle ovulates 895 Gastrulation in the begins at the gray crescent 909 electrodes 928 In pregnancy, hormones from the The dorsal lip of the blastopore Ion transporters and channels extraembryonic membranes generate membrane take over 896 organizes embryo formation 910 potentials 928 Childbirth is triggered by Transcription factors and growth Ion channels and their properties hormonal and mechanical can now be studied stimuli 896 factors underlie the organizer’s actions 911 directly 929 43.4 How Can Fertility Be The organizer changes its activity Gated ion channels alter Controlled? 897 as it migrates from the dorsal 930 Humans use a variety of methods lip 912 Graded changes in membrane to control fertility 897 Reptilian and avian gastrulation is potential can integrate an adaptation to yolky information 932 Reproductive help + + solve problems of eggs 913 Sudden changes in Na and K infertility 897 The embryos of placental channels generate action mammals lack yolk 914 potentials 932 Action potentials are conducted Animal 44.4 How Do Organs and Organ along without loss of 44 Development Systems Develop? 915 signal 934 902 The stage is set by the dorsal lip Action potentials jump along of the blastopore 915 myelinated axons 935 44.1 How Does Fertilization Body segmentation develops 45.3 How Do Neurons Activate during neurulation 916 Development? 903 Communicate with Other Hox genes control development Cells? 936 The sperm and the egg make along the anterior–posterior different contributions to the axis 916 The neuromuscular junction is a 903 model chemical 936 Rearrangements of egg 44.5 How Is the Growing The arrival of an cytoplasm set the stage for Embryo Sustained? 918 causes the release of determination 903 Extraembryonic membranes form 936 with contributions from all Synaptic functions involve many germ layers 918 proteins 936 Extraembryonic membranes in The postsynaptic membrane mammals form the responds to placenta 919 neurotransmitter 936 44.6 What Are the Stages can be excitatory or of Human inhibitory 938 Development? 919 The postsynaptic cell sums excitatory and inhibitory Organ development begins in the input 938 first trimester 920 Synapses can be fast or Organ systems grow and mature slow 938 during the second and third Electrical synapses are fast but trimesters 920 do not integrate information Developmental changes continue well 939 throughout life 920

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The vomeronasal organ contains The core of the forebrain controls 950 physiological drives, , Gustation is the of and emotions 970 951 Regions of the telencephalon interact to control behavior 46.3 How Do Sensory Systems and produce Detect Mechanical 970 Forces? 952 The size of the human is off Many different cells respond to the curve 973 touch and pressure 952 47.2 How Is Information are also found in muscles, tendons, and Processed by Neural ligaments 952 Networks? 973 cells are mechanoreceptors Pathways of the autonomic of the auditory and vestibular nervous system control systems 953 involuntary physiological Auditory systems use hair cells to functions 974 The action of a neurotransmitter sense sound 954 The visual system is an example depends on the receptor to of information integration by which it binds 939 Flexion of the basilar membrane is perceived as sound 955 the cerebral cortex 975 To turn off responses, synapses Three-dimensional vision results must be cleared of Various types of damage can result in hearing loss 956 from cortical cells receiving neurotransmitter 940 input from both eyes 977 The diversity of receptors makes The vestibular system uses hair drug specificity possible 940 cells to detect forces of 47.3 Can Higher Functions Be and momentum 956 Understood in Cellular 45.4 How Are Neurons and Glia Terms? 978 Organized into 46.4 How Do Sensory Systems Detect Light? 957 Sleep and dreaming are reflected Information-Processing in electrical patterns in the Rhodopsin is a vertebrate visual Systems? 940 cerebral cortex 978 957 Nervous systems range in Language abilities are localized in have a variety of 940 the left cerebral visual systems 958 The knee-jerk is controlled hemisphere 980 Image-forming eyes evolved by a simple neural Some learning and memory can independently in vertebrates network 941 be localized to specific brain and 958 The vertebrate brain is the seat of areas 981 The vertebrate receives behavioral complexity 943 We still cannot answer the and processes visual question “What is information 959 consciousness?” 982 Sensory Systems Rod and cone cells are the 46 photoreceptors of the 946 vertebrate retina 960 Musculoskeletal Information flows through layers 48 46.1 How Do Sensory Receptor of neurons in the retina 962 Systems 986 Cells Convert Stimuli into Action Potentials? 947 48.1 How Do Muscles Sensory transduction involves The Mammalian Contract? 987 changes in membrane Nervous System: Sliding filaments cause skeletal potentials 947 47 muscle to contract 987 Sensory receptor proteins act on Structure and Higher Actin–myosin interactions cause ion channels 947 Functions 967 filaments to slide 988 Sensation depends on which Actin–myosin interactions are neurons receive action 47.1 How Is the Mammalian controlled by calcium potentials from sensory ions 989 cells 947 Nervous System Organized? 968 is similar to and Many receptors adapt to different from skeletal repeated stimulation 948 Functional organization is based muscle 991 on flow and type of 46.2 How Do Sensory Systems causes slow information 968 contractions of many internal Detect Chemical The anatomical organization of organs 993 Stimuli? 949 the CNS emerges during Olfaction is the sense of development 968 48.2 What Determines smell 949 The transmits and Some chemoreceptors detect processes information 969 Performance? 994 pheromones 950 The brainstem carries out many autonomic functions 969

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O2 availability decreases with Closed circulatory systems altitude 1007 circulate blood through a system of blood vessels 1026 CO2 is lost by diffusion 1008 49.2 What Adaptations 50.2 How Have Vertebrate Maximize Respiratory Gas Circulatory Systems Exchange? 1008 Evolved? 1027 Respiratory organs have large Circulation in fish is a single surface areas 1008 circuit 1028 Ventilation and of gas Lungfish evolved a gas- exchange surfaces maximize organ 1028 partial pressure Amphibians have partial gradients 1009 separation of systemic and Insects have airways throughout pulmonary circulation 1029 their bodies 1009 Reptiles have exquisite control of The strength of a muscle Fish gills use countercurrent flow pulmonary and systemic contraction depends on how to maximize gas circulation 1029 many fibers are contracting exchange 1009 Birds and mammals have fully and at what rate 994 Birds use unidirectional ventilation separated pulmonary and Muscle fiber types determine to maximize gas systemic circuits 1030 endurance and strength 995 exchange 1010 50.3 How Does the Mammalian A muscle has an optimal length Tidal ventilation produces dead Function? 1030 for generating maximum that limits tension 996 efficiency 1012 Blood flows from right heart to to left heart to Exercise increases muscle 49.3 How Do Human Lungs body 1030 strength and endurance 996 Work? 1013 The heartbeat originates in the Muscle ATP supply limits cardiac muscle 1032 performance 997 Respiratory tract secretions aid ventilation 1013 A conduction system coordinates muscle has the greatest the contraction of of cycling 997 Lungs are ventilated by pressure changes in the thoracic muscle 1034 48.3 How Do Skeletal Systems cavity 1015 Electrical properties of ventricular and Muscles Work muscles sustain heart 49.4 How Does Blood Transport contraction 1034 Together? 999 Respiratory ? 1016 A hydrostatic consists of The ECG records the electrical combines reversibly fluid in a muscular cavity 999 activity of the heart 1035 with O 1016 Exoskeletons are rigid outer 2 Myoglobin holds an O 50.4 What Are the Properties of structures 999 2 reserve 1017 Blood and Blood Vertebrate endoskeletons consist Hemoglobin’s affinity for O is Vessels? 1037 of cartilage and bone 999 2 variable 1017 Red blood cells transport develop from connective CO is transported as bicarbonate respiratory gases 1038 tissues 1001 2 ions in the blood 1018 Platelets are essential for blood Bones that have a common joint clotting 1039 49.5 How Is Breathing can work as a lever 1001 Arteries withstand high pressure, Regulated? 1019 arterioles control blood Gas Exchange Breathing is controlled in the flow 1039 49 brainstem 1019 Materials are exchanged in 1005 Regulating breathing requires capillary beds by , feedback 1020 osmosis, and diffusion 1039 49.1 What Physical Factors Blood flows back to the heart Govern Respiratory Gas Circulatory Systems through veins 1041 Exchange? 1006 50 Lymphatic vessels return Diffusion of gases is driven by 1025 interstitial fluid to the partial pressure blood 1042 differences 1006 50.1 Why Do Animals Need a Vascular disease is a killer 1042 Fick’s law applies to all systems of ? 1026 50.5 How Is the Circulatory gas exchange 1006 Some animals do not have a System Controlled and Air is a better respiratory medium circulatory system 1026 Regulated? 1043 than water 1007 Circulatory systems can be open Autoregulation matches local High temperatures create or closed 1026 blood flow to local respiratory problems for Open circulatory systems move need 1044 aquatic animals 1007 1026

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Arterial pressure is regulated by Herbivores rely on Marine fishes must conserve hormonal and neural microorganisms to digest water 1077 mechanisms 1044 cellulose 1063 Terrestrial amphibians and reptiles 51.4 How Is the Flow of must avoid 1077 Nutrition, Nutrients Controlled and Mammals can produce highly Regulated? 1064 concentrated 1078 51 Digestion, and The is the functional unit Hormones control many digestive of the vertebrate 1078 functions 1065 Absorption 1048 Blood is filtered into Bowman’s The directs the traffic of the capsule 1078 51.1 What Do Animals Require molecules that fuel The renal tubules convert metabolism 1065 from Food? 1049 glomerular filtrate to Energy needs and expenditures The brain plays a major role in urine 1079 can be measured 1049 regulating food intake 1067 Sources of energy can be stored 52.5 How Does the Mammalian in the body 1050 Salt and Water Kidney Produce Food provides carbon Concentrated for biosynthesis 1051 Balance and Urine? 1079 Animals need mineral elements 52 Nitrogen Excretion Kidneys produce urine and the for a variety of functions 1052 bladder stores it 1080 Animals must obtain 1071 have a regular from food 1053 arrangement in the Nutrient deficiencies result in 52.1 How Do Excretory kidney 1081 diseases 1054 Systems Maintain Most of the glomerular filtrate is Homeostasis? 1072 reabsorbed by the proximal 51.2 How Do Animals Ingest convoluted tubule 1082 and Digest Food? 1054 Water enters or leaves cells by osmosis 1072 The loop of Henle creates a The food of herbivores is often concentration gradient in the low in energy and hard to Excretory systems control renal medulla 1082 digest 1054 extracellular fluid osmolarity and composition 1072 Water permeability of kidney must find, capture, tubules depends on water and kill prey 1055 Aquatic invertebrates can channels 1084 conform to or regulate their Vertebrate species have osmotic and ionic The distal convoluted tubule fine- distinctive teeth 1055 environments 1072 tunes the composition of the urine 1084 Digestion usually begins in a Vertebrates are osmoregulators body cavity 1056 and ionic regulators 1073 Urine is concentrated in the Tubular guts have an opening at collecting 1084 each end 1056 52.2 How Do Animals Excrete The kidneys help regulate acid– Digestive enzymes break down Nitrogen? 1074 base balance 1084 complex food Animals excrete nitrogen in a Kidney failure is treated with molecules 1057 number of forms 1074 dialysis 1085 51.3 How Does the Vertebrate Most species produce more than 52.6 How Are Kidney Functions Gastrointestinal System one nitrogenous waste 1074 Regulated? 1087 Function? 1058 52.3 How Do Glomerular filtration rate is The vertebrate gut consists of Excretory Systems regulated 1087 concentric tissue layers 1058 Work? 1075 Mechanical activity moves food The protonephridia of through the gut and aids flatworms excrete digestion 1059 water and conserve Chemical digestion begins in the salts 1075 mouth and the 1060 The metanephridia of The stomach gradually releases annelids process its contents to the small coelomic fluid 1075 intestine 1061 Malpighian tubules of Most chemical digestion occurs in insects use active the 1061 transport to excrete Nutrients are absorbed in the wastes 1076 small intestine 1063 52.4 How Do Absorbed nutrients go to the Vertebrates liver 1063 Maintain Salt Water and ions are absorbed in and Water the 1063 Balance? 1077

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Regulation of GFR uses feedback Knockout experiments can reveal Cost–benefit analysis can be information from the distal the roles of specific applied to tubule 1087 genes 1096 behavior 1104 Blood osmolarity and blood are controlled by gene 53.5 What Physiological pressure are regulated by cascades 1097 ADH 1088 Mechanisms Underlie 53.3 How Does Behavior The heart produces a hormone Behavior? 1106 that helps lower blood Develop? 1098 Biological rhythms coordinate pressure 1090 Hormones can determine behavior with environmental behavioral potential and cycles 1106 timing 1098 Animals must find their way Animal Behavior Some behaviors can be acquired around their 53 1093 only at certain times 1099 environment 1109 Birdsong learning involves Animals use multiple modalities 53.1 What Are the Origins of genetics, imprinting, and to communicate 1110 hormonal timing 1099 Behavioral Biology? 1094 53.6 How Does Social Behavior The timing and expression of Conditioned are a simple birdsong are under hormonal Evolve? 1113 behavioral mechanism 1094 control 1101 Mating systems maximize the Ethologists focused on the fitness of both partners 1113 behavior of animals in their 53.4 How Does Behavior Fitness can include more than 1094 Evolve? 1102 your own 1114 Ethologists probed the causes of Animals are faced with many Eusociality is the extreme result behavior 1095 choices 1103 of kin selection 1115 53.2 How Do Genes Influence Behaviors have costs and Group living has benefits and benefits 1103 Behavior? 1096 costs 1116 Territorial behavior carries Can the concepts of Breeding experiments can significant costs 1103 be applied to humans? 1116 produce behavioral phenotypes 1096

PART TEN Ecology Ecology and the 54 Distribution of Life 1121

54.1 What Is Ecology? 1122 Ecology is not the same as 1122 Ecologists study biotic and abiotic components of ecosystems 1122 54.2 Why Do Climates Vary Geographically? 1122 Solar radiation varies over Earth’s surface 1123 input determines atmospheric circulation patterns 1124 54.3 How Is Life Distributed in Terrestrial Environments? Temperate deciduous Atmospheric circulation and change with the seasons 1130 1126 Earth’s rotation result in Temperate grasslands are prevailing 1124 Tundra is found at high latitudes widespread 1131 Prevailing winds drive and high elevations 1128 Hot form around 30° currents 1124 Evergreen trees dominate boreal latitude 1132 Organisms adapt to climatic and temperate evergreen Cold deserts are high and challenges 1125 forests 1129 dry 1133

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Chaparral has hot, dry summers and wet, cool winters 1134 Thorn forests and tropical savannas have similar climates 1135 Tropical deciduous forests occur in hot lowlands 1136 Tropical rainforests are rich in species 1137 54.4 How Is Life Distributed in Aquatic Environments? 1139 The marine can be divided into several life zones 1139 Freshwater may be rich in species 1140 Estuaries have characteristics of both freshwater and marine environments 1141 55.5 How Does 54.5 What Factors Determine Life tables track demographic events 1154 Variation Affect Population the Boundaries of Survivorship curves reflect life Dynamics? 1161 Biogeographic history strategies 1155 Regions? 1141 Many populations live in 55.3 How Do Environmental separated habitat Geological history influences the patches 1161 Conditions Affect Life distribution of Corridors may allow organisms 1141 Histories? 1156 subpopulations to Two scientific advances changed Survivorship and persist 1162 the of determine a population’s 1142 growth rate 1156 55.6 How Can We Use Discontinuous distributions may Life history traits vary with Ecological Principles to result from vicariant or environmental Manage Populations? dispersal events 1143 conditions 1156 1163 Humans exert a powerful Life history traits are influenced Management plans must take life influence on biogeographic by interspecific history strategies into patterns 1145 interactions 1157 account 1163 55.4 What Factors Limit Management plans must be Population Densities? guided by the principles of population dynamics 1163 1157 55 1149 Human has All populations have the potential been exponential 1164 for 1157 55.1 How Do Ecologists Measure Logistic growth occurs as a population approaches its Species Interactions Populations? 1150 1158 Ecologists use a variety of Population growth can be limited 56 and Coevolution approaches to count and track by density-dependent or 1169 individuals 1150 density-independent Ecologists can estimate factors 1159 56.1 What Types of Interactions population densities from Different population regulation samples 1151 Do Ecologists factors lead to different life Study? 1170 A population’s age structure history strategies 1159 influences its capacity to Several ecological factors explain Interactions among species can grow 1151 species’ characteristic be grouped into several A population’s pattern population densities 1159 categories 1170 reflects how individuals are Some newly introduced species Interaction types are not always distributed in space 1152 reach high population clear-cut 1171 densities 1160 Some types of interactions result 55.2 How Do Ecologists Study in coevolution 1171 Population Dynamics? Evolutionary history may explain 1153 species abundances 1160 56.2 How Do Antagonistic Demographic events determine Interactions Evolve? 1172 the size of a population 1153

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Predator–prey interactions result in a range of adaptations 1172 Herbivory is a widespread interaction 1175 Parasite–host interactions may be pathogenic 1176 56.3 How Do Mutualistic Interactions Evolve? 1177 Some mutualistic partners exchange food for care or transport 1178 Some mutualistic partners exchange food or for defense 1178 Plants and exchange food for pollen transport 1180 Plants and frugivores exchange food for seed transport 1181 56.4 What Are the Outcomes of ? 1182 57.3 What Patterns of Species Ecosystems and Competition is widespread Diversity Have Ecologists because all species share Observed? 1195 58 Global Ecology 1182 Diversity comprises both the 1207 Interference competition may number and the relative restrict habitat use 1183 abundance of species 1195 Exploitation competition may 58.1 How Does Ecologists have observed through the Global lead to coexistence 1183 latitudinal gradients in Species may compete indirectly diversity 1196 ? 1208 for a 1184 The theory of island Energy flows and chemicals cycle Competition may determine a biogeography suggests that through ecosystems 1208 species’ niche 1184 and extinction The geographic distribution of rates determine diversity on energy flow is uneven 1208 islands 1196 Human activities modify the flow of energy 1210 Community 57.4 How Do Disturbances 57 Ecology 1188 Affect Ecological 58.2 How Do Materials Move Communities? 1199 through the Global 57.1 What Are Ecological Succession is the predictable Ecosystem? 1210 Communities? 1189 pattern of change in a Elements move between biotic Energy enters communities community after a and abiotic compartments of through primary disturbance 1199 ecosystems 1211 producers 1189 Both facilitation and inhibition The atmosphere contains large Consumers use diverse sources of influence succession 1201 pools of the gases required by energy 1190 Cyclical succession requires living organisms 1211 Fewer individuals and less adaptation to periodic The terrestrial surface is can be supported at disturbances 1201 influenced by slow geological higher trophic levels 1190 Heterotrophic succession processes 1213 and species diversity generates distinctive Water transports elements among are linked 1192 communities 1202 compartments 1213 57.5 How Does Species Richness Fire is a major mover of 57.2 How Do Interactions elements 1214 among Species Influence Influence Community Communities? 1193 Stability? 1202 58.3 How Do Specific Nutrients Cycle through the Global Species interactions can cause Species richness is associated trophic cascades 1193 with productivity and Ecosystem? 1214 stability 1202 Keystone species have Water cycles rapidly through the disproportionate effects on Diversity, productivity, and ecosystem 1215 their communities 1194 stability differ between natural The has been and managed altered by human communities 1202 activities 1216

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The nitrogen cycle depends on We can predict the effects of APPENDIX A both biotic and abiotic human activities on The Tree of Life 1248 processes 1218 biodiversity 1231 APPENDIX B The burning of fossil fuels affects 59.3 What Human Activities the cycle 1219 Primer 1255 Threaten Species The global cycle Persistence? 1232 APPENDIX C lacks a significant atmospheric Some Measurements Used in Habitat losses endanger component 1220 Biology 1264 Other biogeochemical cycles are species 1233 also important 1221 has driven many ANSWERS TO CHAPTER REVIEW Biogeochemical cycles species to extinction 1234 QUESTIONS A-1 interact 1221 Invasive predators, competitors, and pathogens threaten many GLOSSARY G-1 58.4 What and Services species 1235 ILLUSTRATION CREDITS C-1 Do Ecosystems Rapid can cause Provide? 1223 species 1236 INDEX I-1 58.5 How Can Ecosystems Be 59.4 What Strategies Are Used Sustainably to Protect Managed? 1224 Biodiversity? 1237 Protected areas preserve habitat and prevent Biodiversity and overexploitation 1237 Degraded ecosystems can be 59 Conservation restored 1237 Biology 1228 Disturbance patterns sometimes need to be restored 1239 59.1 What Is Conservation Ending trade is crucial to saving Biology? 1229 some species 1240 Conservation biology aims to Species invasions must be protect and manage controlled or prevented 1241 biodiversity 1229 Biodiversity has economic Biodiversity has great value to value 1241 human society 1230 Changes in human-dominated can help protect 59.2 How Do Conservation biodiversity 1243 Biologists Predict Changes Captive breeding programs can in Biodiversity? 1230 maintain a few species 1244 Our knowledge of biodiversity is Earth is not a ship, a spaceship, incomplete 1230 or an airplane 1244

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