Biology: How Life Works 3rd Edition

Description

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