Biology: How Life Works 3rd Edition

Cover Page......Page 2
Halftitle Page......Page 3
Title Page......Page 4
Copyright Page......Page 5
Dedication......Page 7
About the Authors......Page 8
Biology: How Life Works......Page 16
Connected Visual Tools......Page 22
Connecting Skills......Page 25
Connected Learning Tools......Page 27
Connected Assessment......Page 29
Connecting Through Launchpad......Page 31
What’s New in the Third Edition?......Page 33
List of New Topics & Other Revisions......Page 37
Table of Contents......Page 41
Praise for How Life Works......Page 43
Acknowledgments......Page 45
Brief Contents......Page 102
Contents......Page 105
Part 1 From Cells to Organisms......Page 189
Chapter 1 Life: Chemical, Cellular, and Evolutionary Foundations......Page 190
Observation allows us to draw tentative explanations called hypotheses......Page 194
A hypothesis makes predictions that can be tested by observation and experiments......Page 196
How do we know? What caused the extinction of the dinosaurs?......Page 201
A theory is a general explanation of natural phenomena supported by many experiments and observations......Page 203
1.2 Chemical and Physical Principles......Page 206
The living and nonliving worlds follow the same chemical rules and obey the same physical laws......Page 208
Scientific inquiry shows that living organisms come from other living organisms......Page 214
How do we know? Can living organisms arise from nonliving matter?......Page 215
How do we know? Can microscopic life arise from nonliving matter?......Page 217
1.3 The Cell......Page 220
Nucleic acids store and transmit information needed for growth, function, and reproduction......Page 222
Membranes define cells and spaces within cells......Page 226
Metabolism converts energy from the environment into a form that can be used by cells......Page 229
A virus is genetic material that requires a cell to carry out its functions......Page 230
Variation in populations provides the raw material for evolution......Page 232
Evolution predicts a nested pattern of relatedness among species, depicted as a tree......Page 235
Evolution can be studied by means of experiments......Page 239
How do we know? Can evolution be demonstrated in the laboratory?......Page 240
Basic features of anatomy, physiology, and behavior shape ecological systems......Page 244
Ecological interactions play an important role in evolution......Page 247
1.6 The Human Footprint......Page 249
Core Concepts Summary......Page 254
Case 1: Life’s Origins: Information, Homeostasis, and Energy......Page 258
Chapter 2 The Molecules of Life......Page 266
Atoms consist of protons, neutrons, and electrons......Page 269
Electrons occupy regions of space called orbitals......Page 271
Elements have recurring, or periodic, chemical properties......Page 273
A covalent bond results when two atoms share electrons......Page 276
A polar covalent bond is characterized by unequal sharing of electrons......Page 279
An ionic bond forms between oppositely charged ions......Page 280
A chemical reaction involves breaking and forming chemical bonds......Page 282
Water is a polar molecule......Page 284
A hydrogen bond is an interaction between a hydrogen atom and an electronegative atom......Page 285
Hydrogen bonds give water many unusual properties......Page 286
pH is a measure of the concentration of protons in solution......Page 289
2.4 Carbon......Page 291
Carbon atoms form four covalent bonds......Page 292
Carbon-based molecules are structurally and functionally diverse......Page 293
2.5 Organic Molecules......Page 298
Functional groups add chemical character to carbon chains......Page 299
Proteins are composed of amino acids......Page 300
Nucleic acids encode genetic information in their nucleotide sequence......Page 302
Complex carbohydrates are made up of simple sugars......Page 307
Lipids are hydrophobic molecules......Page 311
How did the molecules of life form?......Page 317
How do we know? Could the building blocks of organic molecules have been generated on the early Earth?......Page 318
Experiments show how life’s building blocks can form macromolecules......Page 320
Core Concepts Summary......Page 323
Chapter 3 Nucleic Acids and Transcription......Page 327
3.1 Chemical Composition and Structure of DNA......Page 331
How do we know? Can genetic information be transmitted between two strains of bacteria?......Page 332
How do we know? Which molecule carries genetic information?......Page 334
A DNA strand consists of subunits called nucleotides......Page 336
DNA is a linear polymer of nucleotides linked by phosphodiester bonds......Page 339
Cellular DNA molecules take the form of a double helix......Page 342
3.2 DNA Structure And Function......Page 351
DNA molecules are copied in the process of replication, which relies on base pairing......Page 352
RNA is an intermediary between DNA and protein......Page 354
3.3 Transcription......Page 358
RNA is a polymer of nucleotides in which the 5-carbon sugar is ribose......Page 359
What kinds of nucleic acids were present in the earliest cells?......Page 361
In transcription, DNA is used as a template to make complementary RNA......Page 363
Transcription starts at a promoter and ends at a terminator......Page 364
RNA polymerase adds successive nucleotides to the 3' end of the transcript......Page 369
The RNA polymerase complex is a molecular machine that opens, transcribes, and closes duplex DNA......Page 371
Primary transcripts in prokaryotes are translated immediately......Page 374
Primary transcripts in eukaryotes undergo several types of chemical modification......Page 376
Some RNA transcripts are processed differently from protein-coding transcripts and have functions of their own......Page 381
Core Concepts Summary......Page 383
Chapter 4 Translation and Protein Structure......Page 386
Amino acids differ in their side chains......Page 389
Successive amino acids in proteins are connected by peptide bonds......Page 395
The sequence of amino acids dictates protein folding, which determines function......Page 397
Secondary structures result from hydrogen bonding in the polypeptide backbone......Page 400
Tertiary structures result from interactions between amino acid side chains......Page 403
Polypeptide subunits can come together to form quaternary structures......Page 409
Chaperones help some proteins fold properly......Page 410
How do we know? What determines secondary and tertiary structure of proteins?......Page 406
4.2 Protein Synthesis......Page 412
Translation uses many molecules found in all cells......Page 413
The genetic code shows the correspondence between codons and amino acids......Page 419
How do we know? How was the genetic code deciphered?......Page 420
Translation consists of initiation, elongation, and termination......Page 424
How did the genetic code originate?......Page 429
Most proteins are composed of modular folding domains......Page 431
Amino acid sequences evolve through mutation and selection......Page 433
Visual Synthesis: Gene Expression......Page 437
Core Concepts Summary......Page 439
Chapter 5 Organizing Principles: Lipids, Membranes, and Cell Compartments......Page 442
Cell membranes are composed of two layers of lipids......Page 446
How did the first cell membranes form?......Page 449
Cell membranes are dynamic......Page 450
Proteins associate with cell membranes in different ways......Page 453
How do we know? Do proteins move in the plane of the membrane?......Page 456
The plasma membrane maintains homeostasis......Page 459
Passive transport involves diffusion......Page 460
Primary active transport uses the energy of ATP......Page 465
Secondary active transport is driven by an electrochemical gradient......Page 467
Many cells maintain size and composition using active transport......Page 469
The cell wall provides another means of maintaining cell shape......Page 471
Eukaryotes and prokaryotes differ in internal organization......Page 475
Prokaryotic cells lack a nucleus and extensive internal compartmentalization......Page 477
Eukaryotic cells have a nucleus and specialized internal structures......Page 478
5.4 The Endomembrane System......Page 482
The endomembrane system compartmentalizes the cell......Page 483
The nucleus houses the genome and is the site of RNA synthesis......Page 485
The endoplasmic reticulum is involved in protein and lipid synthesis......Page 486
The Golgi apparatus modifies and sorts proteins and lipids......Page 488
Lysosomes degrade macromolecules......Page 491
Protein sorting directs proteins to their proper location in or out of the cell......Page 492
Mitochondria provide the eukaryotic cell with most of its usable energy......Page 499
Chloroplasts capture energy from sunlight......Page 501
Core Concepts Summary......Page 503
Chapter 6 Making Life Work: Capturing and Using Energy......Page 507
6.1 An Overview of Metabolism......Page 510
Organisms can be classified according to their energy and carbon sources......Page 511
Metabolism is the set of chemical reactions that sustain life......Page 513
6.2 Kinetic and Potential Energy......Page 515
Kinetic energy and potential energy are two forms of energy......Page 516
Chemical energy is a form of potential energy......Page 517
ATP is a readily accessible form of cellular energy......Page 518
The first law of thermodynamics: energy is conserved......Page 521
The second law of thermodynamics: energy transformations always result in an increase in disorder in the universe......Page 522
A chemical reaction occurs when molecules interact......Page 526
The laws of thermodynamics determine whether a chemical reaction requires or releases energy available to do work......Page 528
The hydrolysis of ATP is an exergonic reaction......Page 531
Non-spontaneous reactions are often coupled to spontaneous reactions......Page 533
Enzymes reduce the activation energy of a chemical reaction......Page 537
Enzymes form a complex with reactants and products......Page 540
Enzymes are highly specific......Page 546
How do we know? Do enzymes form complexes with substrates?......Page 543
Enzyme activity can be influenced by inhibitors and activators......Page 547
Allosteric enzymes regulate key metabolic pathways......Page 548
What naturally occurring elements might have spurred the first reactions that led to life?......Page 551
Core Concepts Summary......Page 553
Chapter 7 Cellular Respiration: Harvesting Energy from Carbohydrates and Other Fuel Molecules......Page 557
Cellular respiration uses chemical energy stored in molecules such as carbohydrates and lipids to produce ATP......Page 561
ATP is generated by substrate-level phosphorylation and oxidative phosphorylation......Page 564
Redox reactions play a central role in cellular respiration......Page 565
Cellular respiration occurs in four stages......Page 569
Glycolysis is the partial breakdown of glucose......Page 574
The oxidation of pyruvate connects glycolysis to the citric acid cycle......Page 578
The citric acid cycle produces ATP and reduced electron carriers......Page 581
What were the earliest energy-harnessing reactions?......Page 584
The electron transport chain transfers electrons and pumps protons......Page 587
The proton gradient is a source of potential energy......Page 590
ATP synthase converts the energy of the proton gradient into the energy of ATP......Page 591
How do we know? Can a proton gradient drive the synthesis of ATP?......Page 593
Fermentation extracts energy from glucose in the absence of oxygen......Page 599
How did early cells meet their energy requirements?......Page 603
Excess glucose is stored as glycogen in animals and starch in plants......Page 607
Sugars other than glucose contribute to glycolysis......Page 608
Fatty acids and proteins are useful sources of energy......Page 610
The intracellular level of ATP is a key regulator of cellular respiration......Page 612
Exercise requires several types of fuel molecules and the coordination of metabolic pathways......Page 616
Core Concepts Summary......Page 618
Chapter 8 Photosynthesis: Using Sunlight to Build Carbohydrates......Page 623
Photosynthesis is widely distributed......Page 626
Photosynthesis is a redox reaction......Page 628
How do we know? Does the oxygen released by photosynthesis come from H2O or C2O?......Page 631
The photosynthetic electron transport chain takes place in specialized membranes......Page 634
8.2 The Calvin Cycle......Page 637
NADPH is the reducing agent of the Calvin cycle......Page 638
The steps of the Calvin cycle were determined using radioactive CO2......Page 640
How do we know? How is CO2 incorporated into carbohydrates?......Page 641
Carbohydrates are stored in the form of starch......Page 642
Chlorophyll is the major entry point for light energy in photosynthesis......Page 645
Antenna chlorophyll passes light energy to reaction centers......Page 648
How do we know? Do chlorophyll molecules operate on their own or in groups?......Page 650
The photosynthetic electron transport chain connects two photosystems......Page 652
The accumulation of protons in the thylakoid lumen drives the synthesis of ATP......Page 656
Cyclic electron transport increases the production of ATP......Page 657
Excess light energy can cause damage......Page 660
Photorespiration leads to a net loss of energy and carbon......Page 663
Photosynthesis captures just a small percentage of incoming solar energy......Page 666
How did early cells use sunlight to meet their energy requirements?......Page 670
Visual Synthesis: Harnessing Energy: Photosynthesis and Cellular Respiration......Page 676
Core Concepts Summary......Page 678
Case 2: Cancer: Cell Signaling, Form, and Division......Page 682
Chapter 9 Cell Signaling......Page 689
Cells communicate using chemical signals that bind to receptors......Page 692
Signaling involves receptor activation, signal transduction, response, and termination......Page 697
The response of a cell to a signaling molecule depends on the cell type......Page 699
Endocrine signaling acts over long distances......Page 701
Signaling can occur over short distances......Page 702
How do we know? Where do growth factors come from?......Page 703
Signaling can occur by direct cell–cell contact......Page 708
9.3 Signaling Receptors......Page 710
Receptors for polar signaling molecules are located on the cell surface......Page 711
Receptors for nonpolar signaling molecules are located in the interior of the cell......Page 712
Cell-surface receptors act like molecular switches......Page 713
9.4 G Protein-Coupled Receptors......Page 717
The first step in cell signaling is receptor activation......Page 718
Signals are often amplified in the cytosol......Page 720
Signals lead to a cellular response......Page 722
Signaling pathways are eventually terminated......Page 723
9.5 Receptor Kinases......Page 725
Receptor kinases phosphorylate each other, activate intracellular signaling pathways, lead to a response, and are terminated......Page 726
How do cell signaling errors lead to cancer?......Page 730
Signaling pathways are integrated to produce a response in a cell......Page 731
Core Concepts Summary......Page 734
Chapter 10 Cell and Tissue Architecture: Cytoskeleton, Cell Junctions, and Extracellular Matrix......Page 738
Tissues and organs are communities of cells......Page 743
The structure of skin relates to its function......Page 744
10.2 The Cytoskeleton......Page 748
Microtubules and microfilaments are polymers of protein subunits......Page 749
Microtubules and microfilaments are dynamic structures......Page 750
Motor proteins associate with microtubules and microfilaments to cause movement......Page 752
Intermediate filaments are polymers of proteins that vary according to cell type......Page 759
The cytoskeleton is an ancient feature of cells......Page 762
Cell adhesion molecules allow cells to attach to other cells and to the extracellular matrix......Page 765
Anchoring junctions connect adjacent cells and are reinforced by the cytoskeleton......Page 768
Tight junctions prevent the movement of substances through the space between cells......Page 771
Molecules pass between cells through communicating junctions......Page 772
The extracellular matrix of plants is the cell wall......Page 775
The extracellular matrix is abundant in connective tissues of animals......Page 778
How do cancer cells spread throughout the body?......Page 783
Extracellular matrix proteins influence cell shape and gene expression......Page 785
How do we know? Can extracellular matrix proteins influence gene expression?......Page 786
Core Concepts Summary......Page 791
Chapter 11 Cell Division: Variation, Regulation, and Cancer......Page 795
Prokaryotic cells divide by binary fission......Page 798
Eukaryotic cells divide by mitotic cell division......Page 801
The cell cycle describes the life cycle of a eukaryotic cell......Page 802
The DNA of eukaryotic cells is organized as chromosomes......Page 806
Prophase: Chromosomes condense and become visible......Page 809
Prometaphase: Chromosomes attach to the mitotic spindle......Page 811
Anaphase: Sister chromatids fully separate......Page 813
The parent cell divides into two daughter cells by cytokinesis......Page 814
11.3 Meiotic Cell Division......Page 817
Pairing of homologous chromosomes is unique to meiosis......Page 818
Crossing over between DNA molecules results in exchange of genetic material......Page 820
The first meiotic division reduces the chromosome number......Page 822
The second meiotic division resembles mitosis......Page 825
Division of the cytoplasm often differs between the sexes......Page 830
Meiosis is the basis of sexual reproduction......Page 831
Nondisjunction in meiosis results in extra or missing chromosomes......Page 834
Some human disorders result from nondisjunction......Page 836
Extra or missing sex chromosomes have fewer effects than extra autosomes......Page 838
11.5 Cell Cycle Regulation......Page 843
Protein phosphorylation controls passage through the cell cycle......Page 844
How do we know? How is progression through the cell cycle controlled?......Page 846
Different cyclin–CDK complexes regulate each stage of the cell cycle......Page 849
Cell cycle progression requires successful passage through multiple checkpoints......Page 850
Oncogenes promote cancer......Page 854
Proto-oncogenes are genes that when mutated may cause cancer......Page 858
Tumor suppressors block specific steps in the development of cancer......Page 859
How do we know? Can a virus cause cancer?......Page 855
Most cancers require the accumulation of multiple mutations......Page 860
Visual Synthesis: Cellular Communities......Page 863
Core Concepts Summary......Page 864
Case 3: Your Personal Genome You, from A to T......Page 870
Chapter 12 DNA Replication and Manipulation......Page 878
During DNA replication, the parental strands separate and new partners are made......Page 881
How do we know? How is DNA replicated?......Page 883
New DNA strands grow by the addition of nucleotides to the 3′ end......Page 887
In replicating DNA, one daughter strand is synthesized continuously and the other in a series of short pieces......Page 890
A small stretch of RNA is needed to begin synthesis of a new DNA strand......Page 892
Synthesis of the leading and lagging strands is coordinated......Page 893
DNA polymerase is self-correcting because of its proofreading function......Page 896
Replication of DNA in chromosomes starts at many places almost simultaneously......Page 900
Telomerase restores tips of linear chromosomes shortened during DNA replication......Page 902
The polymerase chain reaction selectively amplifies regions of DNA......Page 909
Electrophoresis separates DNA fragments by size......Page 913
Restriction enzymes cleave DNA at particular short sequences......Page 916
DNA strands can be separated and brought back together again......Page 919
DNA sequencing makes use of the principles of DNA replication......Page 922
What new technologies are used to sequence your personal genome?......Page 928
12.4 Genetic Engineering......Page 931
Recombinant DNA combines DNA molecules from two or more sources......Page 932
Recombinant DNA is the basis of genetically modified organisms......Page 935
DNA editing can be used to alter gene sequences almost at will......Page 937
Core Concepts Summary......Page 942
Chapter 13 Genomes......Page 945
13.1 Genome Sequencing......Page 948
Complete genome sequences are assembled from smaller pieces......Page 949
How do we know? How are whole genomes sequenced?......Page 950
Sequences that are repeated complicate sequence assembly......Page 952
Why sequence your personal genome?......Page 955
Genome annotation identifies various types of sequence......Page 957
Genome annotation includes searching for sequence motifs......Page 960
Comparison of genomic DNA with messenger RNA reveals the intron–exon structure of genes......Page 963
An annotated genome summarizes knowledge, guides research, and reveals evolutionary relationships among organisms......Page 964
The HIV genome illustrates the utility of genome annotation and comparison......Page 966
Gene number is not a good predictor of biological complexity......Page 970
Viruses, bacteria, and archaeons have small, compact genomes......Page 972
Among eukaryotes, no relationship exists between genome size and organismal complexity......Page 973
About half of the human genome consists of transposable elements and other types of repetitive DNA......Page 977
Bacterial cells package their DNA as a nucleoid composed of many loops......Page 981
Eukaryotic cells package their DNA as one molecule per chromosome......Page 983
The human genome consists of 22 pairs of chromosomes and two sex chromosomes......Page 987
Organelle DNA forms nucleoids that differ from those in bacteria......Page 992
13.5 Viruses and Viral Genomes......Page 994
Viruses can be classified by their genomes......Page 995
The host range of a virus is determined by viral and host surface proteins......Page 998
Viruses have diverse sizes and shapes......Page 1000
Core Concepts Summary......Page 1004
Chapter 14 Mutation and Genetic Variation......Page 1007
14.1 Genotype and Phenotype......Page 1011
Genotype is the genetic makeup of a cell or organism, and the phenotype is its observed characteristics......Page 1012
Some genetic differences are harmful......Page 1013
Some genetic differences are neutral......Page 1015
A few genetic differences are beneficial......Page 1016
The effect of a mutation may depend on the genotype and environment......Page 1018
Mutation of individual nucleotides is rare, but mutation across the genome is common......Page 1022
Only germ-line mutations are transmitted to progeny......Page 1025
What can your personal genome tell you about your genetic risk factors for cancer?......Page 1029
Mutations are random with regard to an organism’s needs......Page 1030
How do we know? Do mutations occur randomly, or are they directed by the environment?......Page 1031
Point mutations are changes in a single nucleotide......Page 1036
The effect of a point mutation depends in part on where in the genome it occurs......Page 1038
Small insertions and deletions involve several nucleotides......Page 1041
Some mutations are due to the insertion of a transposable element......Page 1045
How do we know? What causes sectoring in corn kernels?......Page 1046
Duplications and deletions result in gain or loss of DNA......Page 1050
Gene families arise from gene duplication and divergence......Page 1052
Copy-number variation constitutes a significant proportion of genetic variation......Page 1053
Tandem repeats are useful in DNA typing......Page 1055
An inversion has a chromosomal region reversed in orientation......Page 1058
A reciprocal translocation joins segments from nonhomologous chromosomes......Page 1059
DNA damage can affect both DNA backbone and bases......Page 1061
Most DNA damage is corrected by specialized repair enzymes......Page 1063
Core Concepts Summary......Page 1069
Chapter 15 Mendelian Inheritance......Page 1074
Early theories of heredity predicted the transmission of acquired characteristics......Page 1077
Belief in blending inheritance discouraged studies of hereditary transmission......Page 1079
Mendel’s experimental organism was the garden pea......Page 1082
In crosses, one of the traits was dominant in the offspring......Page 1085
15.3 Segregation......Page 1090
Genes come in pairs that segregate in the formation of reproductive cells......Page 1092
The principle of segregation was tested by predicting the outcome of crosses......Page 1095
A testcross is a mating to an individual with the homozygous recessive genotype......Page 1097
Segregation of alleles reflects the separation of chromosomes in meiosis......Page 1099
Dominance is not universally observed......Page 1100
The principles of transmission genetics are statistical and are stated in terms of probabilities......Page 1102
Mendelian segregation preserves genetic variation......Page 1105
Independent assortment is observed when genes segregate independently of one another......Page 1107
How do we know? How are single-gene traits inherited?......Page 1112
Independent assortment reflects the random alignment of chromosomes in meiosis......Page 1115
Phenotypic ratios can be modified by interactions between genes......Page 1117
15.5 Human Genetics......Page 1121
Dominant traits appear in every generation......Page 1122
Recessive traits skip generations......Page 1124
Many genes have multiple alleles......Page 1126
Incomplete penetrance and variable expression can obscure inheritance patterns......Page 1128
Core Concepts Summary......Page 1133
Chapter 16 Inheritance of Sex Chromosomes, Linked Genes, and Organelles......Page 1137
In many animals, sex is genetically determined and associated with chromosomal differences......Page 1140
Segregation of the sex chromosomes predicts a 1 : 1 ratio of females to males......Page 1143
X-linked inheritance was discovered through studies of male fruit flies with white eyes......Page 1146
Genes in the X chromosome exhibit a crisscross inheritance pattern......Page 1147
X-linkage provided the first experimental evidence that genes are in chromosomes......Page 1153
Genes in the X chromosome show characteristic patterns in human pedigrees......Page 1157
Nearby genes in the same chromosome show linkage......Page 1162
The frequency of recombination is a measure of the genetic distance between linked genes......Page 1168
Genetic mapping assigns a location to each gene along a chromosome......Page 1171
Genetic risk factors for disease can be localized by genetic mapping......Page 1174
How do we know? Can recombination be used to construct a genetic map of a chromosome?......Page 1172
Y-linked genes are transmitted from father to son......Page 1178
How can the Y chromosome be used to trace ancestry?......Page 1180
Mitochondrial and chloroplast genomes often show uniparental inheritance......Page 1184
Maternal inheritance is characteristic of mitochondrial diseases......Page 1186
How can mitochondrial DNA be used to trace ancestry?......Page 1188
Core Concepts Summary......Page 1190
Chapter 17 The Genetic and Environmental Basis of Complex Traits......Page 1194
17.1 Heredity and Environment......Page 1198
Complex traits are affected by the environment......Page 1199
Complex traits are affected by multiple genes......Page 1202
Genetic and environmental effects can interact in unpredictable ways......Page 1207
For complex traits, offspring resemble parents but show regression toward the mean......Page 1212
Heritability is the proportion of the total variation due to genetic differences among individuals......Page 1216
17.3 Twin Studies......Page 1222
Twin studies help separate the effects of genes and environment in differences among individuals......Page 1223
How do we know? What is the relative importance of genes and of the environment for complex traits?......Page 1225
17.4 Complex Traits in Health and Disease......Page 1230
Most common diseases and birth defects are affected by many genes, each with a relatively small effect......Page 1231
Human height is affected by hundreds of genes......Page 1235
Can personalized medicine lead to effective treatments of common diseases?......Page 1236
Core Concepts Summary......Page 1240
Chapter 18 Genetic and Epigenetic Regulation......Page 1243
Gene expression can be influenced by chemical modification of DNA or histones......Page 1247
Gene expression can be regulated at the level of an entire chromosome......Page 1253
Transcription is a key control point in gene expression......Page 1258
RNA processing is also important in gene regulation......Page 1260
Small regulatory RNAs inhibit translation or promote mRNA degradation......Page 1266
Translational regulation controls the rate, timing, and location of protein synthesis......Page 1268
Protein structure and chemical modification modulate protein effects on phenotype......Page 1270
How do lifestyle choices affect expression of your personal genome?......Page 1272
18.3 Transcriptional Regulation in Prokaryotes......Page 1275
Transcriptional regulation can be positive or negative......Page 1276
Lactose utilization in E. coli is the pioneering example of transcriptional regulation......Page 1280
How do we know? How does lactose lead to the production of active β-galactosidase enzyme?......Page 1281
The repressor protein binds with the operator and prevents transcription, but not in the presence of lactose......Page 1285
The function of the lactose operon was revealed by genetic studies......Page 1287
The lactose operon is also positively regulated by CRP–cAMP......Page 1289
Transcriptional regulation determines the outcome of infection by a bacterial virus......Page 1291
Visual Synthesis: Virus: A Genome in Need of a Cell......Page 1296
Core Concepts Summary......Page 1298
Chapter 19 Genes and Development......Page 1302
The fertilized egg is a totipotent cell......Page 1305
Cellular differentiation increasingly restricts alternative fates......Page 1308
How do we know? How do stem cells lose their ability to differentiate into any cell type?......Page 1310
Can cells with your personal genome be reprogrammed for new therapies?......Page 1315
Drosophila development proceeds through egg, larval, and adult stages......Page 1318
The egg is a highly polarized cell......Page 1320
Development proceeds by progressive regionalization and specification......Page 1325
Homeotic genes determine where different body parts develop in the organism......Page 1329
Animals have evolved a wide variety of eyes......Page 1335
Pax6 is a master regulator of eye development......Page 1337
Floral differentiation is a model for plant development......Page 1344
The identity of the floral organs is determined by combinatorial control......Page 1346
A signaling molecule can cause multiple responses in the cell......Page 1352
Developmental signals are amplified and expanded......Page 1355
Visual Synthesis: Genetic Variation and Inheritance......Page 1358
Core Concepts Summary......Page 1360
Case 4 Malaria, Coevolution of Humans and a Parasite......Page 1364
Chapter 20 Evolution: How Genotypes and Phenotypes Change over Time......Page 1371
Population genetics is the study of patterns of genetic variation......Page 1374
Mutation and recombination are the two sources of genetic variation......Page 1376
To understand patterns of genetic variation, we require information about allele frequencies......Page 1379
Early population geneticists relied on observable traits and gel electrophoresis to measure variation......Page 1381
How do we know? How did gel electrophoresis allow us to detect genetic variation?......Page 1383
DNA sequencing is the gold standard for measuring genetic variation......Page 1386
Evolution is a change in allele or genotype frequency over time......Page 1388
The Hardy–Weinberg equilibrium describes situations in which allele and genotype frequencies do not change......Page 1389
The Hardy–Weinberg equilibrium relates allele frequencies and genotype frequencies......Page 1391
The Hardy–Weinberg equilibrium is the starting point for population genetic analysis......Page 1396
Natural selection brings about adaptations......Page 1398
The Modern Synthesis combines Mendelian genetics and Darwinian evolution......Page 1403
Natural selection increases the frequency of advantageous mutations and decreases the frequency of deleterious mutations......Page 1404
Which genetic differences have made some individuals more and some less susceptible to malaria?......Page 1406
Natural selection can be stabilizing, directional, or disruptive......Page 1408
How do we know? How far can artificial selection be taken?......Page 1411
Sexual selection increases an individual’s reproductive success......Page 1413
Genetic drift is a change in allele frequency due to chance......Page 1416
Genetic drift has a large effect in small populations......Page 1418
Migration reduces genetic variation between populations......Page 1420
Nonrandom mating alters genotype frequencies without affecting allele frequencies......Page 1421
20.6 Molecular Evolution......Page 1424
The molecular clock relates the amount of sequence difference between species and the time since the species diverged......Page 1426
The rate of the molecular clock varies......Page 1427
Core Concepts Summary......Page 1431
Chapter 21 Species and Speciation......Page 1435
Species are reproductively isolated from other species......Page 1437
The BSC is more useful in theory than in practice......Page 1440
Hybridization complicates the BSC......Page 1444
Ecology and evolution can extend the BSC......Page 1446
Pre-zygotic isolating factors occur before egg fertilization......Page 1450
Post-zygotic isolating factors occur after egg fertilization......Page 1452
Speciation is a by-product of the genetic divergence of separated populations......Page 1454
Allopatric speciation is speciation that results from the geographical separation of populations......Page 1456
Dispersal and vicariance can isolate populations from each other......Page 1457
How do we know? Can vicariance cause speciation?......Page 1458
Co-speciation is speciation that occurs in response to speciation in another species......Page 1467
How did malaria come to infect humans?......Page 1468
Sympatric populations—those in the same place—may undergo speciation......Page 1469
Speciation can occur instantaneously......Page 1473
Speciation can occur with or without natural selection......Page 1479
Visual Synthesis: Speciation......Page 1480
Core Concepts Summary......Page 1482
Chapter 22 Evolutionary Patterns: Phylogeny and Fossils......Page 1485
22.1 Reading a Phylogenetic Tree......Page 1488
Phylogenetic trees provide hypotheses of evolutionary relationships......Page 1489
The search for sister groups lies at the heart of phylogenetics......Page 1493
A monophyletic group consists of a common ancestor and all its descendants......Page 1495
Taxonomic classifications are information storage and retrieval systems......Page 1497
Homology is similarity by common descent......Page 1501
Shared derived characters enable biologists to reconstruct evolutionary history......Page 1505
The simplest tree is often favored among multiple possible trees......Page 1507
Molecular data complement comparative morphology in reconstructing phylogenetic history......Page 1511
Phylogenetic trees can help solve practical problems......Page 1517
How do we know? Did an HIV-positive dentist spread the AIDS virus to his patients?......Page 1518
Fossils provide unique information......Page 1522
Fossils provide a selective record of past life......Page 1524
Geologic data indicate the age and environmental setting of fossils......Page 1530
Fossils can contain unique combinations of characters......Page 1536
How do we know? Do fossils bridge the evolutionary gap between fish and tetrapod vertebrates?......Page 1538
Rare mass extinctions have altered the course of evolution......Page 1540
Phylogeny and fossils complement each other......Page 1545
Agreement between phylogenies and the fossil record provides strong evidence of evolution......Page 1546
Core Concepts Summary......Page 1550
Chapter 23 Human Origins and Evolution......Page 1554
Comparative anatomy shows that the human lineage branches off the great apes tree......Page 1557
Molecular analysis reveals that the human lineage split from the chimpanzee lineage about 5–7 million years ago......Page 1559
How do we know? How closely related are humans and chimpanzees?......Page 1560
The fossil record gives us direct information about our evolutionary history......Page 1563
Studies of mitochondrial DNA reveal that modern humans evolved in Africa relatively recently......Page 1574
How do we know? When and where did the most recent common ancestor of all living humans live?......Page 1575
Neanderthals disappear from the fossil record as modern humans appear, but have contributed to the modern human gene pool......Page 1580
Bipedalism was a key innovation......Page 1584
Adult humans share many features with juvenile chimpanzees......Page 1587
Humans have large brains relative to body size......Page 1591
The human and chimpanzee genomes help us identify genes that make us human......Page 1593
Humans have very little genetic variation......Page 1597
The prehistory of humans influenced the distribution of genetic variation......Page 1598
The recent spread of modern humans means that there are few genetic differences between groups......Page 1600
Some human differences have likely arisen by natural selection......Page 1602
Which human genes are under selection for resistance to malaria?......Page 1604
Culture changes rapidly......Page 1607
Is culture uniquely human?......Page 1610
Is language uniquely human?......Page 1611
Is consciousness uniquely human?......Page 1613
Core Concepts Summary......Page 1616
Part 2 From Organisms to the Environment......Page 1620
Case 5 The Human Microbiome, Diversity Within......Page 1621
Chapter 24 Bacteria and Archaea......Page 1630
The bacterial cell is small but powerful......Page 1633
Diffusion limits cell size in bacteria......Page 1636
Horizontal gene transfer promotes genetic diversity in bacteria......Page 1639
Archaea form a second prokaryotic domain......Page 1643
24.2 An Expanded Carbon Cycle......Page 1648
Many photosynthetic bacteria do not produce oxygen......Page 1650
Many bacteria respire without oxygen......Page 1655
Photoheterotrophs obtain energy from light but obtain carbon from preformed organic molecules......Page 1657
Chemoautotrophy is a uniquely prokaryotic metabolism......Page 1658
Bacteria and archaeons dominate Earth’s sulfur cycle......Page 1661
The nitrogen cycle is also driven by bacteria and archaeons......Page 1664
24.4 Bacterial Diversity......Page 1669
How do we know? How many kinds of bacterium live in the oceans?......Page 1670
Bacterial phylogeny is a work in progress......Page 1673
What, if anything, is a bacterial species?......Page 1678
Proteobacteria are the most diverse bacteria......Page 1679
The gram-positive bacteria include organisms that cause and cure disease......Page 1680
Photosynthesis is widely distributed on the bacterial tree......Page 1681
24.5 Archaeal Diversity......Page 1685
The archaeal tree has anaerobic, hyperthermophilic organisms near its base......Page 1687
The Archaea include several groups of acid-loving microorganisms......Page 1688
Only Archaea produce methane as a by-product of energy metabolism......Page 1689
Thaumarchaeota may be the most abundant cells in the deep ocean......Page 1690
How do we know? How abundant are archaeons in the oceans?......Page 1691
24.6 The Evolutionary History of Prokaryotes......Page 1695
Life originated early in our planet’s history......Page 1697
Prokaryotes have coevolved with eukaryotes......Page 1698
How do intestinal bacteria influence human health?......Page 1701
Core Concepts Summary......Page 1706
Chapter 25 Eukaryotic Cells: Origins and Diversity......Page 1711
25.1 A Review of the Eukaryotic Cell......Page 1714
Internal protein scaffolding and dynamic membranes organize the eukaryotic cell......Page 1715
In eukaryotic cells, energy metabolism is localized in mitochondria and chloroplasts......Page 1717
The organization of the eukaryotic genome also helps explain eukaryotic diversity......Page 1719
Sex promotes genetic diversity in eukaryotes and gives rise to distinctive life cycles......Page 1720
What role did symbiosis play in the origin of chloroplasts?......Page 1725
How do we know? What is the evolutionary origin of chloroplasts?......Page 1727
What role did symbiosis play in the origin of mitochondria?......Page 1731
How did the eukaryotic cell originate?......Page 1733
In the oceans, many single-celled eukaryotes harbor symbiotic bacteria......Page 1737
25.3 Eukaryotic Diversity......Page 1741
Our own group, the opisthokonts, is the most diverse eukaryotic superkingdom......Page 1744
Amoebozoans include slime molds that produce multicellular structures......Page 1747
Archaeplastids, which include land plants, are photosynthetic organisms......Page 1751
Stramenopiles, alveolates, and rhizarians dominate eukaryotic diversity in the oceans......Page 1755
How do we know? How did photosynthesis spread through the Eukarya?......Page 1761
Fossils show that eukaryotes existed at least 1800 million years ago......Page 1768
Protists have continued to diversify during the age of animals......Page 1771
Core Concepts Summary......Page 1774
Chapter 26 Being Multicellular......Page 1778
Simple multicellularity is widespread among eukaryotes......Page 1781
Complex multicellularity evolved several times......Page 1785
Diffusion is effective only over short distances......Page 1790
Animals achieve large size by circumventing limits imposed by diffusion......Page 1791
Complex multicellular organisms have structures specialized for bulk flow......Page 1793
Complex multicellularity requires adhesion between cells......Page 1796
How did animal cell adhesion originate?......Page 1797
How do we know? How do bacteria influence the life cycles of choanoflagellates?......Page 1798
Complex multicellularity requires communication between cells......Page 1800
Complex multicellularity requires a genetic program for coordinated growth and cell differentiation......Page 1803
Cell walls shape patterns of growth and development in plants......Page 1808
Animal cells can move relative to one another......Page 1811
26.5 The Evolution of Complex Multicellularity......Page 1814
Fossil evidence of complex multicellular organisms is first observed in rocks deposited 575–555 million years ago......Page 1815
Oxygen is necessary for complex multicellular life......Page 1818
Land plants evolved from green algae that could carry out photosynthesis on land......Page 1820
Regulatory genes played an important role in the evolution of complex multicellular organisms......Page 1822
How do we know? What controls color pattern in butterfly wings?......Page 1824
Core Concepts Summary......Page 1827
Case 6 Agriculture, Feeding a Growing Population......Page 1831
Chapter 27 Plant Form, Function, and Evolutionary History......Page 1839
Land plants share many cellular features with green algae......Page 1842
Bryophytes rely on surface water for hydration......Page 1845
Water pulled from the soil moves through vascular plants by bulk flow......Page 1847
Vascular plants produce four major organ types......Page 1848
CO2 uptake results in water loss......Page 1852
The cuticle restricts water loss from leaves but inhibits the uptake of CO2......Page 1855
Stomata allow leaves to regulate water loss and carbon gain......Page 1857
CAM plants use nocturnal CO2 storage to avoid water loss during the day......Page 1859
C4 plants suppress photorespiration by concentrating CO2 in bundle-sheath cells......Page 1861
How do we know? Does C4 photosynthesis suppress photorespiration?......Page 1865
27.3 Water Transport......Page 1868
Xylem provides a low-resistance pathway for the movement of water......Page 1869
Water is pulled through xylem by an evaporative pump......Page 1874
How do we know? Do plants generate negative pressures?......Page 1875
Xylem transport is at risk of conduit collapse and cavitation......Page 1881
Phloem transports carbohydrates from sources to sinks......Page 1885
Carbohydrates are pushed through phloem by an osmotic pump......Page 1888
Phloem feeds both the plant and the rhizosphere......Page 1891
27.5 Uptake of Water and Nutrients......Page 1893
Plants obtain nutrients from the soil......Page 1894
Nutrient uptake by roots is highly selective......Page 1896
Nutrient uptake requires energy......Page 1899
Mycorrhizae enhance nutrient uptake......Page 1900
Symbiotic nitrogen-fixing bacteria supply nitrogen to both plants and ecosystems......Page 1902
How has nitrogen availability influenced agricultural productivity?......Page 1905
Core Concepts Summary......Page 1909
Chapter 28 Plant Reproduction: Finding Mates and Dispersing Young......Page 1913
28.1 Alternation of Generations......Page 1916
The algal sister groups of land plants have one multicellular generation in their life cycle......Page 1917
Land plants have two multicellular generations in their life cycle......Page 1919
Bryophytes illustrate how the alternation of generations allows the dispersal of spores in the air......Page 1922
Dispersal enhances reproductive fitness in several ways......Page 1924
Spore-dispersing vascular plants have free-living gametophytes and sporophytes......Page 1925
28.2 Seed Plants......Page 1929
The seed plant life cycle is distinguished by four major steps......Page 1930
Pine trees illustrate how the transport of pollen in air allows fertilization to occur in the absence of external sources of water......Page 1932
Seeds enhance the establishment of the next sporophyte generation......Page 1935
Flowers are reproductive shoots specialized for the transfer and receipt of pollen......Page 1939
The diversity of floral morphology is related to modes of pollination......Page 1944
How do we know? How do long nectar spurs evolve?......Page 1947
Angiosperms have mechanisms to increase outcrossing......Page 1951
Angiosperms delay provisioning their ovules until after fertilization......Page 1953
Fruits enhance the dispersal of seeds......Page 1956
How did scientists increase crop yields during the Green Revolution?......Page 1960
Asexually produced plants disperse with and without seeds......Page 1963
Core Concepts Summary......Page 1966
Chapter 29 Plant Growth and Development......Page 1969
29.1 Shoot Growth and Development......Page 1972
Stems grow by adding new cells at their tips......Page 1973
Stem elongation occurs just below the apical meristem......Page 1974
Stems branch by producing new apical meristems......Page 1976
The shoot apical meristem controls the production and arrangement of leaves......Page 1977
Young leaves develop vascular connections to the stem......Page 1983
Flower development terminates the growth of shoot meristems......Page 1985
Hormones affect the growth and differentiation of plant cells......Page 1987
Polar transport of auxin guides the placement of leaf primordia and the development of vascular connections with the stem......Page 1991
What is the developmental basis for the shorter stems of high-yielding rice and wheat?......Page 1995
Cytokinins, in combination with other hormones, control the outgrowth of branches......Page 1996
Shoots produce two types of lateral meristem......Page 2000
The vascular cambium produces secondary xylem and phloem......Page 2001
The cork cambium produces an outer protective layer......Page 2005
Wood has both support and transport functions......Page 2007
Roots grow by producing new cells at their tips......Page 2010
Root elongation and vascular development are coordinated......Page 2012
The formation of new root apical meristems allows roots to branch......Page 2014
The structures and functions of root systems are diverse......Page 2016
Plants orient the growth of their stems and roots by light and gravity......Page 2019
How do we know? How do plants grow toward light?......Page 2020
Seeds can delay germination if they detect the presence of plants overhead......Page 2026
How do we know? How do seeds detect the presence of plants growing overhead?......Page 2027
Plants grow taller and branch less when growing in the shade of other plants......Page 2031
Roots elongate more and branch less when water is scarce......Page 2033
Exposure to wind results in shorter and stronger stems......Page 2034
Flowering time is affected by day length......Page 2036
Plants use their internal circadian clock and photoreceptors to determine day length......Page 2039
Vernalization prevents plants from flowering until winter has passed......Page 2041
Plants use day length as a cue to prepare for winter......Page 2042
Core Concepts Summary......Page 2044
Chapter 30 Plant Defense......Page 2049
30.1 Protection Against Pathogens......Page 2052
Plant pathogens infect and exploit host plants by a variety of mechanisms......Page 2053
Plants are able to detect and respond to pathogens......Page 2056
Plants respond to infections by isolating infected regions......Page 2059
Mobile signals trigger defenses in uninfected tissues......Page 2061
How do we know? Can plants develop immunity to specific pathogens?......Page 2062
Plants defend against viral infections by producing siRNA......Page 2064
A pathogenic bacterium provides a way to modify plant genomes......Page 2066
Plants use mechanical and chemical defenses to avoid being eaten......Page 2069
Diverse chemical compounds deter herbivores......Page 2073
Some plants provide food and shelter for ants, which actively defend them......Page 2076
Grasses can regrow quickly following grazing by mammals......Page 2079
Some defenses are always present, whereas others are turned on in response to a threat......Page 2082
Plants can sense and respond to herbivores......Page 2083
Plants produce volatile signals that attract insects that prey upon herbivores......Page 2086
How do we know? Can plants communicate?......Page 2087
Nutrient-rich environments select for plants that allocate more resources to growth than to defense......Page 2088
Exposure to multiple threats can lead to trade-offs......Page 2091
30.4 Defense and Plant Diversity......Page 2093
The evolution of new defenses may allow plants to diversify......Page 2094
Pathogens, herbivores, and seed predators can increase plant diversity......Page 2095
Can modifying plants genetically protect crops from herbivores and pathogens?......Page 2097
Core Concepts Summary......Page 2103
Chapter 31 Plant Diversity......Page 2107
31.1 Major Themes in the Evolution of Plant Diversity......Page 2110
Four major transformations in life cycle and structure characterize the evolutionary history of plants......Page 2111
Plant diversity has changed over time......Page 2115
Bryophytes are small and tough......Page 2119
The small gametophytes and unbranched sporophytes of bryophytes are adaptations for reproducing on land......Page 2122
Bryophytes exhibit several cases of convergent evolution with the vascular plants......Page 2124
Sphagnum moss plays an important role in the global carbon cycle......Page 2125
31.3 Spore-Dispersing Vascular Plants......Page 2129
Rhynie chert fossils provide a window into the early evolution of vascular plants......Page 2130
Lycophytes evolved leaves and roots independently from all other vascular plants......Page 2132
Ancient lycophytes included giant trees that dominated coal swamps about 320 million years ago......Page 2134
Ferns and horsetails are morphologically and ecologically diverse......Page 2139
How do we know? Did woody plants evolve more than once?......Page 2135
Fern diversity has been strongly affected by the evolution of angiosperms......Page 2142
31.4 Gymnosperms......Page 2144
Seed plants have been the dominant plants on land for more than 200 million years......Page 2145
Cycads and ginkgos were once both diverse and widespread......Page 2147
Conifers are woody plants that thrive in dry and cold climates......Page 2149
Gnetophytes are gymnosperms that have independently evolved xylem vessels and double fertilization......Page 2152
Several innovations increased the efficiency of the angiosperm life cycle and xylem transport......Page 2154
Angiosperm diversity may result in part from coevolutionary interactions with animals and other organisms......Page 2156
Monocots are diverse in shape and size despite not forming a vascular cambium......Page 2160
How do we know? When did grasslands expand over the land surface?......Page 2164
Eudicots are the most diverse group of angiosperms......Page 2166
What can be done to protect the genetic diversity of crop species?......Page 2170
Visual Synthesis: Angiosperms: Structure and Function......Page 2173
Core Concepts Summary......Page 2175
Chapter 32 Fungi......Page 2180
Hyphae permit fungi to explore their environment for food resources......Page 2183
Fungi transport materials within their hyphae......Page 2185
Not all fungi produce hyphae......Page 2187
Fungi are principal decomposers of plant tissues......Page 2188
Fungi are important plant and animal pathogens......Page 2192
Many fungi form symbiotic associations with plants and animals......Page 2196
Lichens are symbioses between a fungus and a green alga or a cyanobacterium......Page 2198
Fungi proliferate and disperse using spores......Page 2203
Multicellular fruiting bodies facilitate the dispersal of sexually produced spores......Page 2205
Sexual reproduction in fungi often includes a stage in which haploid cells fuse, but nuclei do not......Page 2208
How do we know? What determines the shape of fungal spores that are ejected into the air?......Page 2207
Genetically distinct mating types promote outcrossing......Page 2212
Parasexual fungi generate genetic diversity by asexual means......Page 2213
Fungi are highly diverse......Page 2215
Chytrids are aquatic fungi that lack hyphae......Page 2217
Zygomycetes produce hyphae undivided by septa......Page 2219
Glomeromycetes form endomycorrhizae......Page 2221
The Dikarya produce regular septa during mitosis......Page 2222
Ascomycetes are the most diverse group of fungi......Page 2224
Basidiomycetes include smuts, rusts, and mushrooms......Page 2230
How do we know? Can a fungus influence the behavior of an ant?......Page 2227
How do fungi threaten global wheat production?......Page 2236
Core Concepts Summary......Page 2240
Case 7: Biology-Inspired Design: Using Nature to Solve Problems......Page 2243
Chapter 33 Animal Form, Function, and Evolutionary History......Page 2253
What is an animal?......Page 2256
Animals can be classified based on type of symmetry......Page 2257
Many animals have a brain and specialized sensory organs at the front of the body......Page 2261
Some animals also show segmentation......Page 2263
Animals can be classified based on the number of their germ layers......Page 2264
Molecular sequence comparisons have confirmed some relationships and raised new questions......Page 2268
Can we mimic the form and function of animals to build robots?......Page 2270
33.2 Tissues and Organs......Page 2273
Most animals have four types of tissues......Page 2274
Tissues are organized into organs that carry out specific functions......Page 2279
Homeostasis is the active maintenance of stable conditions inside of cells and organisms......Page 2281
Homeostasis is often achieved by negative feedback......Page 2283
33.4 Evolutionary History......Page 2286
Fossils and phylogeny show that animal forms were initially simple but rapidly evolved complexity......Page 2287
The animal body plans we see today emerged during the Cambrian Period......Page 2288
Five mass extinctions have changed the trajectory of animal evolution during the past 500 million years......Page 2290
Animals began to colonize the land 420 million years ago......Page 2293
How do we know? Do animals tend to get bigger over time?......Page 2296
Core Concepts Summary......Page 2301
Chapter 34 Animal Nervous Systems......Page 2304
Animal nervous systems have three types of nerve cells......Page 2307
Nervous systems range from simple to complex......Page 2309
Neurons share a common organization......Page 2314
Neurons differ in size and shape......Page 2317
Neurons are supported by other types of cells......Page 2318
The resting membrane potential is negative and results in part from the movement of potassium and sodium ions......Page 2320
Neurons are excitable cells that transmit information by action potentials......Page 2323
Neurons propagate action potentials along their axons by sequentially opening and closing adjacent Na+ and K+ ion channels......Page 2328
How do we know? How does electrical activity change during an action potential?......Page 2331
Neurons communicate at synapses......Page 2333
Signals between neurons can be excitatory or inhibitory......Page 2336
Nervous systems are organized into peripheral and central components......Page 2340
Peripheral nervous systems have voluntary and involuntary components......Page 2342
Simple reflex circuits provide rapid responses to stimuli......Page 2345
Sensory receptor cells detect diverse stimuli......Page 2349
Sensory transduction converts a stimulus into an electrical impulse......Page 2350
Chemoreceptors respond to chemical stimuli......Page 2352
Mechanoreceptors detect physical forces......Page 2355
How do cochlear implants work?......Page 2360
Electromagnetic receptors sense light......Page 2361
The brain processes and integrates information received from different sensory systems......Page 2368
The brain is divided into lobes with specialized functions......Page 2370
Information is topographically mapped into the vertebrate cerebral cortex......Page 2372
The brain allows for memory, learning, and cognition......Page 2374
Core Concepts Summary......Page 2377
Chapter 35 Animal Movement: Muscles and Skeletons......Page 2382
35.1 How Muscles Work......Page 2385
Muscles use chemical energy to produce force and movement......Page 2386
Muscles can be striated or smooth......Page 2387
Skeletal and cardiac muscle fibers are organized into repeating contractile units called sarcomeres......Page 2388
Muscles contract by the sliding of myosin and actin protein filaments......Page 2392
Calcium regulates actin–myosin interaction through excitation–contraction coupling......Page 2397
Calmodulin regulates calcium activation and relaxation of smooth muscle......Page 2400
Antagonist pairs of muscles produce reciprocal motions at a joint......Page 2403
Muscle length affects actin–myosin overlap and generation of force......Page 2405
Muscle force and shortening velocity are inversely related......Page 2408
Muscle force is summed by an increase in stimulation frequency and the recruitment of motor units......Page 2411
Skeletal muscles have slow-twitch and fast-twitch fibers......Page 2414
How do different types of muscle fibers affect the speed of animals?......Page 2417
Hydrostatic skeletons support animals by muscles that act on a fluid-filled cavity......Page 2420
Exoskeletons provide hard external support and protection......Page 2423
The rigid bones of vertebrate endoskeletons are jointed for motion and can be repaired if damaged......Page 2426
Vertebrate bones form directly or by forming a cartilage model first......Page 2431
The two main types of bone are compact bone and spongy bone......Page 2433
Bones grow in length and width, and can be repaired......Page 2434
Can we design smart materials to heal bones that are damaged and improve artificial joints?......Page 2436
Joint shape determines range of motion and skeletal muscle organization......Page 2437
Core Concepts Summary......Page 2440
Chapter 36 Animal Endocrine Systems......Page 2444
The endocrine system helps to regulate an organism’s response to its environment......Page 2447
The endocrine system regulates growth and development......Page 2448
How do we know? How are growth and development controlled in insects?......Page 2450
The endocrine system underlies homeostasis......Page 2455
Hormones act specifically on cells that bind the hormone......Page 2462
Two main classes of hormones are peptide and amines, and steroid hormones......Page 2463
Hormonal signals are amplified to produce a strong effect......Page 2470
Hormones are evolutionarily conserved molecules with diverse functions......Page 2473
The pituitary gland integrates diverse bodily functions by secreting hormones in response to signals from the hypothalamus......Page 2475
Many targets of pituitary hormones are endocrine tissues that also secrete hormones......Page 2480
Other endocrine organs have diverse functions......Page 2483
The fight-or-flight response represents a change in set point in many different organs......Page 2485
Local chemical signals regulate neighboring target cells......Page 2489
Pheromones are chemical compounds released into the environment that signal physiological and behavioral changes......Page 2492
Core Concepts Summary......Page 2498
Chapter 37 Animal Cardiovascular and Respiratory Systems......Page 2502
Diffusion governs gas exchange over short distances......Page 2505
Bulk flow moves fluid over long distances......Page 2508
37.2 Respiratory Gas Exchange......Page 2512
Many aquatic animals breathe through gills......Page 2514
Insects breathe air through tracheae......Page 2519
Most terrestrial vertebrates breathe by tidal ventilation of internal lungs......Page 2521
Mammalian lungs are well adapted for gas exchange......Page 2523
The structure of bird lungs allows unidirectional airflow for increased oxygen uptake......Page 2526
Voluntary and involuntary mechanisms control breathing......Page 2528
Blood is composed of fluid and several types of cell......Page 2531
Hemoglobin is an ancient molecule with diverse roles related to oxygen binding and transport......Page 2533
Hemoglobin reversibly binds oxygen......Page 2534
How do we know? What is the molecular structure of hemoglobin and myoglobin?......Page 2535
Myoglobin stores oxygen, enhancing oxygen delivery to muscle mitochondria......Page 2538
Many factors affect hemoglobin–oxygen binding......Page 2540
37.4 Circulatory Systems......Page 2543
Circulatory systems have vessels of different sizes......Page 2546
Arteries are muscular vessels that carry blood away from the heart under high pressure......Page 2548
Veins are thin-walled vessels that return blood to the heart under low pressure......Page 2550
Compounds and fluid move across capillary walls by diffusion, filtration, and osmosis......Page 2551
Hormones and nerves provide homeostatic regulation of blood pressure......Page 2553
37.5 Structure and Function of the Heart......Page 2555
Fishes have two-chambered hearts and a single circulatory system......Page 2556
Amphibians and reptiles have three-chambered hearts and partially divided circulations......Page 2557
Mammals and birds have four-chambered hearts and fully divided pulmonary and systemic circulations......Page 2559
How can we engineer replacement heart valves?......Page 2562
Cardiac muscle cells are electrically connected to contract in synchrony......Page 2564
Heart rate and cardiac output are regulated by the autonomic nervous system......Page 2567
Core Concepts Summary......Page 2570
Chapter 38 Animal Metabolism, Nutrition, and Digestion......Page 2575
Animals rely on anaerobic and aerobic metabolism......Page 2578
Metabolic rate varies with activity level......Page 2582
Metabolic rate is affected by body size......Page 2585
Metabolic rate is linked to body temperature......Page 2589
How do we know? How is metabolic rate affected by running speed and body size?......Page 2587
Visual Synthesis: Homeostasis and Thermoregulation......Page 2591
Energy balance is a form of homeostasis......Page 2592
An animal’s diet must supply nutrients that it cannot synthesize......Page 2594
Suspension filter feeding is common in many aquatic animals......Page 2600
Large aquatic animals apprehend prey by suction feeding and active swimming......Page 2601
Specialized structures allow for capture and mechanical breakdown of food......Page 2603
38.4 Regional Specialization of the Gut......Page 2608
Most animal digestive tracts have three main parts: a foregut, midgut, and hindgut......Page 2609
Digestion begins in the mouth......Page 2611
Further digestion and storage of nutrients take place in the stomach......Page 2613
Final digestion and nutrient absorption take place in the small intestine......Page 2616
The large intestine absorbs water and stores waste......Page 2622
The lining of the digestive tract is composed of distinct layers......Page 2623
Plant-eating animals have specialized digestive tracts adapted to their diets......Page 2625
Core Concepts Summary......Page 2630
Chapter 39 Animal Renal Systems: Water and Waste......Page 2633
Osmosis governs the movement of water across cell membranes......Page 2636
Osmoregulation is the control of osmotic pressure inside cells and organisms......Page 2639
Osmoconformers match their internal solute concentration to that of the environment......Page 2642
Osmoregulators have internal solute concentrations that differ from that of their environment......Page 2643
The excretion of nitrogenous wastes is linked to an animal’s habitat and evolutionary history......Page 2650
Excretory organs work by filtration, reabsorption and secretion......Page 2654
Animals have diverse excretory organs......Page 2658
Vertebrates filter blood under pressure through paired kidneys......Page 2662
39.3 The Mammalian Kidney......Page 2668
The mammalian kidney has an outer cortex and inner medulla......Page 2669
Glomerular filtration isolates wastes carried by the blood along with water and small solutes......Page 2670
The proximal convoluted tubule reabsorbs solutes by active transport......Page 2672
The loop of Henle acts as a countercurrent multiplier to create a concentration gradient from the cortex to the medulla......Page 2673
How do we know? How does the mammalian kidney produce concentrated urine?......Page 2678
The distal convoluted tubule secretes additional wastes......Page 2680
The final concentration of urine is determined in the collecting ducts and is under hormonal control......Page 2681
The kidneys help regulate blood pressure and blood volume......Page 2683
How does dialysis work?......Page 2686
Core Concepts Summary......Page 2689
Chapter 40 Animal Reproduction and Development......Page 2692
Asexual reproduction produces clones......Page 2695
Sexual reproduction involves the formation and fusion of gametes......Page 2698
Many species reproduce both sexually and asexually......Page 2701
Exclusive asexuality is often an evolutionary dead end......Page 2702
How do we know? Do bdelloid rotifers only reproduce asexually?......Page 2707
Fertilization can take place externally or internally......Page 2711
r-strategists and K-strategists differ in number of offspring and parental care......Page 2713
Animals either lay eggs or give birth to live young......Page 2715
The male reproductive system is specialized for the production and delivery of sperm......Page 2719
The female reproductive system produces eggs and supports the developing embryo......Page 2724
Hormones regulate the human reproductive system......Page 2728
Male and female gametogenesis have both shared and distinct features......Page 2735
Fertilization occurs when a sperm fuses with an oocyte......Page 2738
The first trimester includes cleavage, gastrulation, and organogenesis......Page 2741
The second and third trimesters are characterized by fetal growth......Page 2748
Childbirth is initiated by hormonal changes......Page 2749
Visual Synthesis: Reproduction and Development......Page 2752
Core Concepts Summary......Page 2754
Chapter 41 Animal Immune Systems......Page 2759
41.1 An Overview of the Immune System......Page 2762
Pathogens cause disease......Page 2763
The immune system distinguishes self from nonself......Page 2764
The immune system consists of innate and adaptive immunity......Page 2766
The skin and mucous membranes provide the first line of defense against infection......Page 2768
White blood cells provide a second line of defense against pathogens......Page 2770
Phagocytes recognize foreign molecules and send signals to other cells......Page 2773
Inflammation is a coordinated response to tissue injury......Page 2774
The complement system participates in the innate and adaptive immune systems......Page 2777
How can we use a protein that circulates in the blood to treat sepsis?......Page 2780
41.3 B Cells and Antibodies......Page 2783
B cells produce antibodies......Page 2785
Mammals produce five classes of antibodies with different functions......Page 2787
Clonal selection is the basis for antibody specificity......Page 2788
Clonal selection explains immunological memory......Page 2791
How do we know? How is antibody diversity generated?......Page 2794
Genomic rearrangement generates antibody diversity......Page 2793
41.4 T Cells and Cell-Mediated Immunity......Page 2801
T cells have T cell receptors on their surface that recognize an antigen in association with MHC proteins......Page 2802
The ability to distinguish between self and nonself is acquired during T cell maturation......Page 2807
The flu virus evades the immune system by antigenic drift and shift......Page 2811
Tuberculosis is caused by a slow-growing, intracellular bacterium......Page 2815
The malaria parasite changes surface molecules by antigenic variation......Page 2817
Core Concepts Summary......Page 2820
Chapter 42 Animal Diversity......Page 2824
42.1 Sponges, Cnidarians, Ctenophores, and Placozoans......Page 2827
Sponges share some features with choanoflagellates but also exhibit adaptations conferred by multicellularity......Page 2830
Cnidarians are the architects of life’s largest constructions: coral reefs......Page 2834
Ctenophores and placozoans represent the extremes of body organization among phyla that branch from early nodes on the animal tree......Page 2840
Branching relationships among early nodes on the animal tree remain uncertain......Page 2843
42.2 Protostome Animals......Page 2846
Lophotrochozoans account for nearly half of all animal phyla, including the diverse and ecologically important annelids and mollusks......Page 2847
Ecdysozoans are animals that episodically molt their external cuticle during growth......Page 2856
How do we know? How did the diverse feeding structures of arthropods arise?......Page 2861
Insects make up the majority of all known animal species and have adaptations that allow them to live in diverse habitats......Page 2868
42.4 Deuterostome Animals......Page 2872
Hemichordates include acorn worms and pterobranchs, and echinoderms include sea stars and sea urchins......Page 2873
Chordates include vertebrates, cephalochordates, and tunicates......Page 2877
42.5 Vertebrates......Page 2881
Fish are the most diverse vertebrate animals......Page 2882
The common ancestor of tetrapods had four limbs......Page 2887
Amniotes evolved terrestrial eggs......Page 2891
Visual Synthesis: Diversity Through Time......Page 2896
Core Concepts Summary......Page 2898
Case 8: Conserving Biodiversity: Rainforest and Coral Reef Hotspots......Page 2902
Chapter 43 Behavior and Behavioral Ecology......Page 2909
Tinbergen asked proximate and ultimate questions about behavior......Page 2912
The fixed action pattern is a stereotyped behavior......Page 2917
The nervous system processes stimuli and evokes behaviors......Page 2920
Hormones can trigger certain behaviors......Page 2922
Breeding experiments can help determine the degree to which a behavior is genetic......Page 2923
Molecular techniques provide new ways of testing the role of genes in behavior......Page 2926
How do we know? Can the same gene influence behavior differently in different species?......Page 2928
Non-associative learning occurs without linking two events......Page 2934
Associative learning occurs when two events are linked......Page 2935
How do we know? To what extent are insects capable of learning?......Page 2937
Learning is an adaptation......Page 2936
Orientation involves a directed response to a stimulus......Page 2942
Biological clocks provide important time cues for many behaviors......Page 2944
How do we know? Does a biological clock play a role in birds’ ability to orient?......Page 2946
Communication is the transfer of information between a sender and a receiver......Page 2950
Some forms of communication are complex and learned during a sensitive period......Page 2953
Various forms of communication can convey specific information......Page 2956
43.6 Social Behavior......Page 2960
Group selection is a weak explanation of altruistic behavior......Page 2962
Reciprocal altruism is one way that altruism can evolve......Page 2963
Kin selection is based on the idea that it is possible to contribute genetically to future generations by helping close relatives......Page 2964
Core Concepts Summary......Page 2971
Chapter 44 Population Ecology......Page 2975
A population includes all the individuals of a species in a particular place......Page 2978
Three key features of a population are its size, range, and density......Page 2979
Ecologists estimate population size by sampling......Page 2984
How do we know? How many butterflies are there in a given population?......Page 2986
Population size is affected by birth, death, immigration, and emigration......Page 2990
Population size increases rapidly when the per capita growth rate is constant over time......Page 2993
Carrying capacity is the maximum number of individuals a habitat can support......Page 2999
Logistic growth produces an S-shaped curve and describes the growth of many natural populations......Page 3000
Factors that influence population growth can be dependent on or independent of population density......Page 3002
Birth and death rates vary with age and environment......Page 3006
Survivorship curves record changes in survival probability over an organism’s life-span......Page 3009
Patterns of survivorship vary among organisms......Page 3012
Reproductive patterns reflect the predictability of a species’ environment......Page 3014
The life history of an organism shows trade-offs among physiological functions......Page 3016
A metapopulation is a group of populations linked by immigrants......Page 3020
How do populations colonize islands?......Page 3025
Core Concepts Summary......Page 3030
Chapter 45 Species interactions and Communities......Page 3033
The niche is a species’ place in nature......Page 3036
The realized niche of a species is more restricted than its fundamental niche......Page 3037
Niches are shaped by evolutionary history......Page 3039
Limited resources foster competition......Page 3042
Species compete for resources other than food......Page 3043
Competitive exclusion prevents two species from occupying the same niche at the same time......Page 3045
Can competition drive species diversification?......Page 3048
Predation, parasitism, and herbivory are interactions in which one species benefits at the expense of another......Page 3049
How do we know? Can predators and prey coexist stably in certain environments?......Page 3051
Mutualisms are interactions between species that benefit both participants......Page 3056
Mutualisms may evolve increasing interdependence......Page 3058
Digestive symbioses recycle plant material......Page 3061
How do we know? Have aphids and their symbiotic bacteria coevolved?......Page 3059
Mutualisms may be obligate or facultative......Page 3063
In some interactions, one partner is unaffected by the interaction......Page 3064
The costs and benefits of species interactions can change over time......Page 3067
Species that live in the same place make up communities......Page 3069
How is biodiversity measured?......Page 3071
Species influence each other in a complex web of interactions......Page 3074
Keystone species have disproportionate effects on communities......Page 3075
Disturbance can modify community composition......Page 3079
Succession describes the community response to new habitats or disturbance......Page 3080
Island biogeography explains species diversity on habitat islands......Page 3084
Visual Synthesis: Succession: Ecology in Microcosm......Page 3089
Core Concepts Summary......Page 3091
Chapter 46 Ecosystem Ecology......Page 3095
46.1 The Short-Term Carbon Cycle......Page 3097
The Keeling curve records changing levels of carbon dioxide in the atmosphere over time......Page 3098
Photosynthesis and respiration are key processes in short-term carbon cycling......Page 3101
Human activities play an important role in the modern carbon cycle......Page 3104
How do we know? How much CO2 was in the atmosphere 1000 years ago?......Page 3105
How do we know? What is the major source of the CO2 that has accumulated in Earth’s atmosphere over the past two centuries?......Page 3108
Records of atmospheric composition over 400,000 years show periodic shifts in CO2 levels......Page 3115
Reservoirs and fluxes are key in long-term carbon cycling......Page 3119
Food webs trace carbon and other elements through communities and ecosystems......Page 3125
Energy as well as carbon is transferred through ecosystems......Page 3128
46.4 Other Biogeochemical Cycles......Page 3134
The nitrogen cycle is closely linked to the carbon cycle......Page 3135
Phosphorus cycles through ecosystems, supporting primary production......Page 3137
Biological diversity reflects the many ways that organisms participate in biogeochemical cycles......Page 3140
Biological diversity can influence primary production and therefore the biological carbon cycle......Page 3142
Biogeochemical cycles weave together biological evolution and environmental change through Earth history......Page 3145
How do we know? Does species diversity promote primary productivity?......Page 3143
Visual Synthesis: Flow of Matter and Energy Through Ecosystems......Page 3150
Core Concepts Summary......Page 3151
Chapter 47 Climate and Biomes......Page 3155
The principal control on Earth’s surface temperature is the angle at which solar radiation strikes the surface......Page 3157
Heat is transported toward the poles by wind and ocean currents......Page 3161
Global circulation patterns determine patterns of rainfall, but topography also matters......Page 3166
47.2 Biomes......Page 3170
Terrestrial biomes reflect the distribution of climate......Page 3171
Aquatic biomes reflect climate, the availability of nutrients and oxygen, and the depth to which sunlight penetrates through water......Page 3194
Marine biomes cover most of our planet’s surface......Page 3198
Global patterns of primary production reflect variations in climate and nutrient availability......Page 3207
How do we know? Does iron limit primary production in some parts of the oceans?......Page 3208
Biodiversity is highest at the equator and lowest toward the poles......Page 3213
How do evolutionary and ecological history explain biodiversity?......Page 3218
Core Concepts Summary......Page 3222
Chapter 48 The Anthropocene: Humans as a Planetary Force......Page 3224
Humans are a major force on the planet......Page 3227
48.2 Human Influence on the Carbon Cycle......Page 3232
As atmospheric carbon dioxide levels have increased, so has mean surface temperature......Page 3233
Changing environments affect species distribution and community composition......Page 3242
How has global environmental change affected coral reefs around the world?......Page 3249
How do we know? How will rising twenty-first-century CO2 levels affect coral reefs?......Page 3254
What can be done?......Page 3257
Nitrogen fertilizer transported to lakes and the sea causes eutrophication......Page 3262
Phosphate fertilizer is also used in agriculture, but has finite sources......Page 3265
Human activities have reduced the quality and size of many habitats, decreasing the number of species they can support......Page 3271
Overexploitation threatens species and disrupts ecological relationships within communities......Page 3274
Humans play an important role in the dispersal of species......Page 3276
Humans have altered the selective landscape for many pathogens......Page 3279
Are amphibians ecology’s “canary in the coal mine”?......Page 3282
48.5 Conservation Biology......Page 3286
What are our conservation priorities?......Page 3287
Conservation biologists have a diverse toolkit for confronting threats to biodiversity......Page 3288
Climate change provides new challenges for conservation biology in the twenty-first century......Page 3291
Sustainable development provides a strategy for conserving biodiversity while meeting the needs of the human population......Page 3294
48.6 Scientists and Citizens in the Twenty-First Century......Page 3297
Core Concepts Summary......Page 3301
Glossary......Page 3305
Index......Page 3447
Back Cover......Page 3695