Life The Science of Biology

by Sadava, David E.; Heller, H. Craig; Orians, Gordon H.; Purves, William K.; Hillis, David M.

• ISBN13: 9780716776710
• ISBN10: 0716776715
• Edition: 8th
• Format: Hardcover
• Copyright: 2006-12-08
• Publisher: W. H. Freeman

Summary

Co-published by Sinauer Associates, Inc., and W. H. Freeman and Company. Visit the Life, Eighth Edition preview site . LIFE HAS EVOLVED. . .from its original publication to this dramatically revitalized Eighth Edition. LIFE has always shown students how biology works, offering an engaging and coherent presentation of the fundamentals of biology by describing the landmark experiments that revealed them. This edition builds on those strengths and introduces several innovations. As with previous editions, theEighth Editionwill also be available in three paperback volumes: Volume I: The Cell and Heredity, Chapters 1-20 Volume II: Evolution, Diversity and Ecology, Chapters 1, 21-33, 52-57 Volume III: Plants and Animals, Chapters 1, 34-51

Table of Contents

Part One The Science and Building Blocks of Life
Studying Life	2	(18)
What Is Biology?	3	(7)
Living organisms consist of cells	4	(1)
The diversity of life is due to evolution by natural selection	5	(2)
Biological information is contained in a genetic language common to all organisms	7	(1)
Cells use nutrients to supply energy and to build new structures	7	(1)
Living organisms control their internal environment	7	(2)
Living organisms interact with one another	9	(1)
Discoveries in biology can be generalized	9	(1)
How Is All Life on Earth Related?	10	(3)
Life arose from nonlife via chemical evolution	10	(1)
Biological evolution began when cells formed	11	(1)
Photosynthesis changed the course of evolution	11	(1)
Eukaryotic cells evolved from prokaryotes	11	(1)
Multicellularity arose and cells became specialized	12	(1)
Biologists can trace the evolutionary Tree of Life	12	(1)
How Do Biologists Investigate Life?	13	(3)
Observation is an important skill	13	(1)
The scientific method combines observation and logic	13	(1)
Good experiments have the potential of falsifying hypotheses	14	(1)
Statistical methods are essential scientific tools	15	(1)
Not all forms of inquiry are scientific	16	(1)
How Does Biology Influence Public Policy?	16	(4)
The Chemistry of Life	20	(18)
What Are the Chemical Elements That Make Up Living Organisms?	21	(4)
An element consists of only one kind of atom	21	(1)
Protons: Their number identifies an element	22	(1)
Neutrons: Their number differs among isotopes	23	(1)
Electrons: Their behavior determines chemical bonding	23	(2)
How Do Atoms Bond to Form Molecules?	25	(5)
Covalent bonds consist of shared pairs of electrons	25	(2)
Multiple covalent bonds	27	(1)
Ionic bonds form by electrical attraction	27	(2)
Hydrogen bonds may form within or between molecules with polar covalent bonds	29	(1)
Polar and nonpolar substances: Each interacts best with its own kind	29	(1)
How Do Atoms Change Partners in Chemical Reactions?	30	(1)
What Properties of Water Make It So Important in Biology?	31	(7)
Water has a unique structure and special properties	31	(1)
Water is the solvent of life	32	(1)
Aqueous solutions may be acidic or basic	33	(1)
pH is the measure of hydrogen ion concentration	34	(1)
Buffers minimize pH change	34	(1)
Life's chemistry began in water	34	(2)
An Overview and a Preview	36	(2)
Macromolecules and the Origin of Life	38	(30)
What Kinds of Molecules Characterize Living Things?	39	(3)
Functional groups give specific properties to molecules	39	(1)
Isomers have different arrangements of the same atoms	40	(1)
The structures of macromolecules reflect their functions	40	(1)
Most macromolecules are formed by condensation and broken down by hydrolysis	41	(1)
What Are the Chemical Structures and Functions of Proteins?	42	(7)
Amino acids are the building blocks of proteins	42	(1)
Peptide bonds form the backbone of a protein	43	(1)
The primary structure of a protein is its amino acid sequence	44	(1)
The secondary structure of a protein requires hydrogen bonding	45	(1)
The tertiary structure of a protein is formed by bending and folding	46	(1)
The quaternary structure of a protein consists of subunits	46	(1)
Both shape and surface chemistry contribute to protein specificity	46	(2)
Environmental conditions affect protein structure	48	(1)
Chaperonins help shape proteins	48	(1)
What Are the Chemical Structures and Functions of Carbohydrates?	49	(5)
Monosaccharides are simple sugars	49	(1)
Glycosidic linkages bond monosac charides	50	(1)
Polysaccharides store energy and provide structural materials	51	(2)
Chemically modified carbohydrates contain additional functional groups	53	(1)
What Are the Chemical Structures and Functions of Lipids?	54	(3)
Fats and oils store energy	55	(1)
Phospholipids form biological membranes	55	(1)
Not all lipids are triglycerides	56	(1)
What Are the Chemical Structures and Functions of Nucleic Acids?	57	(4)
Nucleotides are the building blocks of nucleic acids	57	(2)
The uniqueness of a nucleic acid resides in its nucleotide sequence	59	(1)
DNA reveals evolutionary relationships	60	(1)
Nucleotides have other important roles	60	(1)
How Did Life on Earth Begin?	61	(7)
Could life have come from outside Earth?	61	(1)
Did life originate on Earth?	61	(1)
Chemical evolution may have led to polymerization	62	(1)
RNA may have been the first biological catalyst	62	(1)
Experiments disproved spontaneous generation of life	63	(5)
Part Two Cells and Energy
Cells: The Working Units of Life	68	(28)
What Features of Cells Make Them the Fundamental Unit of Life?	69	(3)
Cell size is limited by the surface area-to-volume ratio	69	(1)
Microscopes are needed to visualize cells	70	(2)
Cells are surrounded by a plasma membrane	72	(1)
Cells are prokaryotic or eukaryotic	72	(1)
What Are the Characteristics of Prokaryotic Cells?	72	(2)
Prokaryotic cells share certain features	72	(1)
Some prokaryotic cells have specialized features	73	(1)
What Are the Characteristics of Eukaryotic Cells?	74	(16)
Compartmentalization is the key to eukaryotic cell function	74	(1)
Organelles can be studied by microscopy or isolated for chemical analysis	75	(1)
Some organelles process information	75	(4)
The endomembrane system is a group of interrelated organelles	79	(3)
Some organelles transform energy	82	(1)
Several other organelles are surrounded by a membrane	83	(3)
The cytoskeleton is important in cell structure	86	(4)
What Are the Roles of Extracellular Structures?	90	(2)
The plant cell wall is an extracellular structure	90	(1)
The extracellular matrix supports tissue functions in animals	91	(1)
How Did Eukaryotic Cells Originate?	92	(4)
The endosymbiosis theory suggests how eukaryotes evolved	92	(1)
Both prokaryotes and eukaryotes continue to evolve	92	(4)
The Dynamic Cell Membrane	96	(22)
What Is the Structure of a Biological Membrane?	97	(5)
Lipids constitute the bulk of a membrane	97	(2)
Membrane proteins are asymmetrically distributed	99	(1)
Membranes are dynamic	100	(1)
Membrane carbohydrates are recognition sites	101	(1)
How Is the Plasma Membrane Involved in Cell Adhesion and Recognition?	102	(3)
Cell recognition and cell adhesion involve proteins at the cell surface	102	(1)
Three types of cell junctions connect adjacent cells	102	(3)
What Are the Passive Processes of Membrane Transport?	105	(6)
Diffusion is the process of random movement toward a state of equilibrium	105	(1)
Simple diffusion takes place through the phospholipid bilayer	106	(1)
Osmosis is the diffusion of water across membranes	106	(2)
Diffusion may be aided by channel proteins	108	(2)
Carrier proteins aid diffusion by binding substances	110	(1)
How Do Substances Cross Membranes against a Concentration Gradient?	111	(2)
Active transport is directional	111	(1)
Primary and secondary active transport rely on different energy sources	111	(2)
How Do Large Molecules Enter and Leave a Cell?	113	(1)
Macromolecules and particles enter the cell by endocytosis	113	(1)
Receptor-mediated endocytosis is highly specific	113	(1)
Exocytosis moves materials out of the cell	114	(1)
What Are Some Other Functions of Membranes?	114	(4)
Energy, Enzymes, and Metabolism	118	(20)
What Physical Principles Underlie Biological Energy Transformations?	119	(4)
There are two basic types of energy and of metabolism	119	(1)
The first law of thermodynamics: Energy is neither created nor destroyed	120	(1)
The second law of thermodynamics: Disorder tends to increase	120	(2)
Chemical reactions release or consume energy	122	(1)
Chemical equilibrium and free energy are related	123	(1)
What Is the Role of ATP in Biochemical Energetics?	123	(2)
ATP hydrolysis releases energy	124	(1)
ATP couples exergonic and endergonic reactions	124	(1)
What Are Enzymes?	125	(3)
For a reaction to proceed, an energy barrier must be overcome	126	(1)
Enzymes bind specific reactant molecules	126	(1)
Enzymes lower the energy barrier but do not affect equilibrium	127	(1)
How Do Enzymes Work?	128	(3)
Molecular structure determines enzyme function	129	(1)
Some enzymes require other molecules in order to function	129	(1)
Substrate concentration affects reaction rate	130	(1)
How Are Enzyme Activities Regulated?	131	(7)
Enzymes can be regulated by inhibitors	131	(1)
Allosteric enzymes control their activity by changing their shape	132	(1)
Allosteric effects regulate metabolism	133	(1)
Enzymes are affected by their environment	133	(5)
Pathways That Harvest Chemical Energy	138	(22)
How Does Glucose Oxidation Release Chemical Energy?	139	(3)
Cells trap free energy while metabolizing glucose	139	(1)
An overview: Harvesting energy from glucose	140	(1)
Redox reactions transfer electrons and energy	140	(1)
The coenzyme NAD is a key electron carrier in redox reactions	141	(1)
What Are the Aerobic Pathways of Glucose Metabolism?	142	(5)
The energy-investing reactions of glycolysis require ATP	142	(2)
The energy-harvesting reactions of glycolysis yield NADH + H+ and ATP	144	(1)
Pyruvate oxidation links glycolysis and the citric acid cycle	144	(1)
The citric acid cycle completes the oxidation of glucose to CO2	145	(2)
The citric acid cycle is regulated by concentrations of starting materials	147	(1)
How Is Energy Harvested from Glucose in the Absence of Oxygen?	147	(1)
How Does the Oxidation of Glucose Form ATP?	148	(5)
The electron transport chain shuttles electrons and releases energy	149	(1)
Proton diffusion is coupled to ATP synthesis	150	(3)
Why Does Cellular Respiration Yield So Much More Energy Than Fermentation?	153	(1)
How Are Metabolic Pathways Interrelated and Controlled?	154	(6)
Catabolism and anabolism involve interconversions of biological monomers	154	(1)
Catabolism and anabolism are integrated	155	(1)
Metabolic pathways are regulated systems	155	(5)
Photosynthesis: Energy from Sunlight	160	(20)
What Is Photosynthesis?	161	(2)
Photosynthesis involves two pathways	162	(1)
How Does Photosynthesis Convert Light Energy into Chemical Energy?	163	(6)
Light behaves as both a particle and a wave	163	(1)
Absorbing a photon excites a pigment molecule	163	(1)
Absorbed wavelengths correlate with biological activity	163	(1)
Photosynthesis uses energy absorbed by several pigments	164	(1)
Light absorption results in photochemical change	165	(1)
Excited chlorophyll in the reaction center acts as a reducing agent	166	(1)
Reduction leads to electron transport	166	(1)
Noncyclic electron transport produces ATP and NADPH	166	(2)
Cyclic electron transport produces ATP but no NADPH	168	(1)
Chemiosmosis is the source of the ATP produced in photophosphorylation	168	(1)
How Is Chemical Energy Used to Synthesize Carbohydrates?	169	(3)
Radioisotope labeling experiments revealed the steps of the Calvin cycle	169	(1)
The Calvin cycle is made up of three processes	170	(2)
Light stimulates the Calvin cycle	172	(1)
How Do Plants Adapt to the Inefficiencies of Photosynthesis?	172	(3)
Rubisco catalyzes RuBP reaction with O2 as well as with CO2	172	(1)
C4 plants can bypass photorespiration	173	(2)
CAM plants also use PEP carboxylase	175	(1)
How Is Photosynthesis Connected to Other Metabolic Pathways in Plants?	175	(5)
Part Three Heredity and the Genome
Chromosomes, The Cell Cycle, and Cell Division	180	(26)
How Do Prokaryotic and Eukaryotic Cells Divide?	181	(3)
Prokaryotes divide by binary fission	181	(1)
Eukaryotic cells divide by mitosis or meiosis	182	(2)
How Is Eukaryotic Cell Division Controlled?	184	(3)
Cyclins and other proteins trigger events in the cell cycle	184	(2)
Growth factors can stimulate cells to divide	186	(1)
What Happens during Mitosis?	187	(6)
Eukaryotic DNA is packed into very compact chromosomes	187	(1)
Overview: Mitosis segregates exact copies of genetic information	188	(1)
The centrosomes determine the plane of cell division	188	(1)
Chromatids become visible and the spindle forms during prophase	189	(1)
Chromosome movements are highly organized	189	(2)
Nuclei re-form during telophase	191	(1)
Cytokinesis is the division of the cytoplasm	192	(1)
What Is the Role of Cell Division in Sexual Life Cycles?	193	(2)
Reproduction by mitosis results in genetic constancy	193	(1)
Reproduction by meiosis results in genetic diversity	193	(2)
The number, shapes, and sizes of the metaphase chromosomes constitute the karyotype	195	(1)
What Happens When a Cell Under goes Meiosis?	195	(7)
The first meiotic division reduces the chromosome number	197	(2)
The second meiotic division separates the chromatids	199	(1)
The activities and movements of chromosomes during meiosis result in genetic diversity	199	(1)
Meiotic errors lead to abnormal chromosome structures and numbers	199	(1)
Polyploids can have difficulty in cell division	200	(2)
How Do Cells Die?	202	(4)
Genetics: Mendel and Beyond	206	(26)
What Are the Mendelian Laws of Inheritance?	207	(10)
Mendel brought new methods to experiments on inheritance	208	(1)
Mendel devised a careful research plan	208	(1)
Mendel's first experiments involved monohybrid crosses	209	(2)
Alleles are different forms of a gene	211	(1)
Mendel's first law says that the two copies of a gene segregate	211	(2)
Mendel verified his hypothesis by performing a test cross	213	(1)
Mendel's second law says that copies of different genes assort independently	213	(1)
Punnett squares or probability calculations: A choice of methods	214	(2)
Mendel's laws can be observed in human pedigrees	216	(1)
How Do Alleles Interact?	217	(2)
New alleles arise by mutation	217	(1)
Many genes have multiple alleles	218	(1)
Dominance is not always complete	218	(1)
In codominance, both alleles at a locus are expressed	219	(1)
Some alleles have multiple phenotypic effects	219	(1)
How Do Genes Interact?	219	(3)
Hybrid vigor results from new gene combinations and interactions	220	(1)
The environment affects gene action	220	(1)
Most complex phenotypes are determined by multiple genes and the environment	221	(1)
What Is the Relationship between Genes and Chromosomes	222	(6)
Genes on the same chromosome are linked	223	(1)
Genes can be exchanged between chromatids	223	(1)
Geneticists can make maps of chromosomes	224	(1)
Linkage is revealed by studies of the sex chromosomes	225	(1)
Genes on sex chromosomes are inherited in special ways	226	(1)
Humans display many sex-linked characters	227	(1)
What Are the Effects of Genes Outside the Nucleus?	228	(4)
DNA and Its Role in Heredity	232	(24)
What Is the Evidence that the Gene is DNA?	233	(5)
DNA from one type of bacterium genetically transforms another type	233	(1)
The transforming principle is DNA	234	(1)
Viral replication experiments confirmed that DNA is the genetic material	235	(2)
Eukaryotic cells can also be genetically transformed by DNA	237	(1)
What Is the Structure of DNA?	238	(3)
The chemical composition of DNA was known	238	(1)
Watson and Crick described the double helix	238	(1)
Four key features define DNA structure	239	(2)
The double-helical structure of DNA is essential to its function	241	(1)
How Is DNA Replicated?	241	(8)
Three modes of DNA replication appeared possible	241	(1)
Meselson and Stahl demonstrated that DNA replication is semiconservative	241	(1)
There are two steps in DNA replication	242	(1)
DNA is threaded through a replication complex	243	(2)
DNA polymerases add nucleotides to the growing chain	245	(2)
Telomeres are not fully replicated	247	(2)
How Are Errors in DNA Repaired?	249	(1)
What Are Some Applications of Our Knowledge of DNA Structure and Replication?	250	(6)
The polymerase chain reaction makes multiple copies of DNA	250	(1)
The nucleotide sequence of DNA can be determined	251	(5)
From DNA to Protein: Genotype to Phenotype	256	(26)
What Is the Evidence that Genes Code for Proteins?	257	(3)
Experiments on bread mold established that genes determine enzymes	257	(1)
One gene determines one polypeptide	258	(2)
How Does Information Flow from Genes to Proteins?	260	(1)
RNA differs from DNA	260	(1)
Information flows in one direction when genes are expressed	260	(1)
RNA viruses are exceptions to the central dogma	261	(1)
How Is the Information Content in DNA Transcribed to Produce RNA?	261	(4)
RNA polymerases share common features	262	(1)
Transcription occurs in three steps	262	(1)
The information for protein synthesis lies in the genetic code	263	(2)
Biologists used artificial messengers to decipher the genetic code	265	(1)
How Is RNA Translated into Proteins?	265	(7)
Transfer RNAs carry specific amino acids and bind to specific codons	266	(1)
Activating enzymes link the right tRNAs and amino acids	267	(1)
The ribosome is the workbench for translation	268	(1)
Translation takes place in three steps	268	(2)
Polysome formation increases the rate of protein synthesis	270	(2)
What Happens to Polypeptides after Translation?	272	(2)
Signal sequences in proteins direct them to their cellular destinations	272	(2)
Many proteins are modified after translation	274	(1)
What Are Mutations?	274	(8)
Point mutations change single nucleotides	275	(1)
Chromosomal mutations are extensive changes in the genetic material	276	(1)
Mutations can be spontaneous or induced	277	(1)
Mutations are the raw material of evolution	277	(5)
The Genetics of Viruses and Prokaryotes	282	(24)
How Do Viruses Reproduce and Transmit Genes?	283	(6)
Viruses are not cells	283	(1)
Viruses reproduce only with the help of living cells	284	(1)
Bacteriophage reproduce by a lytic cycle or a lysogenic cycle	284	(3)
Animal viruses have diverse reproductive cycles	287	(2)
Many plant viruses spread with the help of vectors	289	(1)
How Is Gene Expression Regulated in Viruses?	289	(1)
How Do Prokaryotes Exchange Genes?	290	(6)
The reproduction of prokaryotes gives rise to clones	290	(1)
Bacteria have several ways of recombining their genes	291	(2)
Plasmids are extra chromosomes in bacteria	293	(2)
Transposable elements move genes among plasmids and chromosomes	295	(1)
How Is Gene Expression Regulated in Prokaryotes?	296	(4)
Regulating gene transcription conserves energy	296	(1)
A single promoter can control the transcription of adjacent genes	296	(1)
Operons are units of transcription in prokaryotes	297	(1)
Operator--repressor control induces transcription in the lac operon	297	(1)
Operator-repressor control represses transcription in the trp operon	298	(1)
Protein synthesis can be controlled by increasing promoter efficiency	299	(1)
What Have We Learned from the Sequencing of Prokaryotic Genomes?	300	(6)
The sequencing of prokaryotic genomes has many potential benefits	301	(1)
Will defining the genes required for cellular life lead to artificial life?	302	(4)
The Eukaryotic Genome and Its Expression	306	(26)
What Are the Characteristics of the Eukaryotic Genome?	307	(6)
Model organisms reveal the characteristics of eukaryotic genomes	308	(3)
Eukaryotic genomes contain many repetitive sequences	311	(2)
What Are the Characteristics of Eukaryotic Genes?	313	(3)
Protein-coding genes contain noncoding sequences	313	(2)
Gene families are important in evolution and cell specialization	315	(1)
How Are Eukaryotic Gene Transcripts Processed?	316	(2)
The primary transcript of a protein-coding gene is modified at both ends	316	(1)
Splicing removes introns from the primary transcript	316	(2)
How Is Eukaryotic Gene Transcription Regulated?	318	(6)
Specific genes can be selectively transcribed	318	(4)
Gene expression can be regulated by changes in chromatin structure	322	(2)
Selective gene amplification results in more templates for transcription	324	(1)
How Is Eukaryotic Gene Expression Regulated After Transcription?	324	(2)
Different mRNAs can be made from the same gene by alternative splicing	324	(1)
The stability of mRNA can be regulated	325	(1)
Small RNAs can break down mRNAs	325	(1)
RNA can be edited to change the encoded protein	326	(1)
How Is Gene Expression Controlled During and After Translation?	326	(6)
The initiation and extent of translation can be regulated	326	(1)
Posttranslational controls regulate the longevity of proteins	327	(5)
Part Four Molecular Biology: The Genome in Action
Cell Signaling and Communication	332	(20)
What Are Signals, and How Do Cells Respond to Them?	333	(3)
Cells receive signals from the physical environment and from other cells	333	(1)
A signal transduction pathway involves a signal, a receptor, transduction, and effects	334	(2)
How Do Signal Receptors Initiate a Cellular Response?	336	(3)
Receptors have specific binding sites for their signals	336	(1)
Receptors can be classified by location	336	(3)
How Is a Response to a Signal Transduced through the Cell?	339	(6)
Protein kinase cascades amplify a response to ligand binding	339	(1)
Second messengers can stimulate protein kinase cascades	340	(1)
Second messengers can be derived from lipids	341	(2)
Calcium ions are involved in many signal transduction pathways	343	(1)
Nitric oxide can act as a second messenger	344	(1)
Signal transduction is highly regulated	345	(1)
How Do Cells Change in Response to Signals?	345	(3)
Ion channels open in response to signals	345	(1)
Enzyme activities change in response to signals	346	(1)
Signals can initiate gene transcription	347	(1)
How Do Cells Communicate Directly?	348	(4)
Animal cells communicate by gap junctions	348	(1)
Plant cells communicate by plasmodesmata	348	(4)
Recombinant DNA and Biotechnology	352	(22)
How Are Large DNA Molecules Analyzed?	353	(5)
Restriction enzymes cleave DNA at specific sequences	353	(1)
Gel electrophoresis separates DNA fragments	354	(1)
DNA fingerprinting uses restriction analysis and electrophoresis	355	(1)
The DNA barcode project aims to identify all organisms on Earth	356	(2)
What Is Recombinant DNA?	358	(1)
How Are New Genes Inserted into Cells?	359	(3)
Genes can be inserted into prokaryotic or eukaryotic cells	359	(1)
Vectors carry new DNA into host cells	359	(2)
Reporter genes identify host cells containing recombinant DNA	361	(1)
What Are the Sources of DNA Used in Cloning?	362	(2)
Gene libraries provide collections of DNA fragments	362	(1)
cDNA libraries are constructed from mRNA transcripts	363	(1)
DNA can be synthesized chemically in the laboratory	363	(1)
DNA mutations can be created in the laboratory	363	(1)
What Other Tools Are Used to Manipulate DNA?	364	(3)
Genes can be inactivated by homologous recombination	364	(1)
Antisense RNA and interference RNA can prevent the expression of specific genes	365	(1)
DNA chips can reveal DNA mutations and RNA expression	365	(2)
What Is Biotechnology?	367	(7)
Expression vectors can turn cells into protein factories	367	(1)
Medically useful proteins can be made by biotechnology	368	(1)
DNA manipulation is changing agriculture	369	(2)
There is public concern about biotechnology	371	(3)
Genome Sequencing, Molecular Biology, and Medicine	374	(26)
How Do Defective Proteins Lead to Diseases?	375	(5)
Genetic mutations may make proteins dysfunctional	375	(3)
Prion diseases are disorders of protein conformation	378	(1)
Most diseases are caused by both genes and environment	379	(1)
Human genetic diseases have several patterns of inheritance	379	(1)
What Kinds of DNA Changes Lead to Diseases?	380	(4)
One way to identify a gene is to start with its protein	380	(1)
Chromosome deletions can lead to gene and then protein isolation	381	(1)
Genetic markers can point the way to important genes	381	(1)
Disease-causing mutations may involve any number of base pairs	382	(1)
Expanding triplet repeats demonstrate the fragility of some human genes	382	(1)
DNA changes in males and females can have different consequences	383	(1)
How Does Genetic Screening Detect Diseases?	384	(2)
Screening for disease phenotypes can make use of protein expression	384	(1)
DNA testing is the most accurate way to detect abnormal genes	384	(2)
What Is Cancer?	386	(5)
Cancer cells differ from their normal counterparts	386	(1)
Some cancers are caused by viruses	387	(1)
Most cancers are caused by genetic mutations	387	(1)
Two kinds of genes are changed in many cancers	388	(1)
Several events must occur to turn a normal cell into a malignant cell	389	(2)
How Are Genetic Diseases Treated?	391	(2)
Genetic diseases can be treated by modifying the phenotype	391	(1)
Gene therapy offers the hope of specific treatments	391	(2)
What Have We Learned from the Human Genome Project?	393	(7)
There are two approaches to genome sequencing	393	(1)
The sequence of the human genome contained many surprises	393	(2)
The human genome sequence has many applications	395	(1)
The use of genetic information poses ethical questions	395	(1)
The proteome is more complex than the genome	395	(1)
Systems biology integrates data from genomics and proteomics	396	(4)
Immunology: Gene Expression and Natural Defense Systems	400	(26)
What Are the Major Defense Systems of Animals?	401	(3)
Blood and lymph tissues play important roles in defense systems	402	(1)
White blood cells play many defensive roles	402	(1)
Immune system proteins bind pathogens or signal other cells	403	(1)
What Are the Characteristics of the Nonspecific Defenses?	404	(3)
Barriers and local agents defend the body against invaders	404	(1)
Other nonspecific defenses include specialized proteins and cellular processes	405	(1)
Inflammation is a coordinated response to infection or injury	406	(1)
A cell signaling pathway stimulates the body's defenses	407	(1)
How Does Specific Immunity Develop?	407	(4)
The specific immune system has four key traits	407	(1)
Two types of specific immune responses interact	408	(1)
Genetic changes and clonal selection generate the specific immune response	408	(1)
Immunity and immunological memory result from clonal selection	409	(1)
Vaccines are an application of immunological memory	409	(1)
Animals distinguish self from nonself and tolerate their own antigens	410	(1)
What Is the Humoral Immune Response?	411	(3)
Some B cells develop into plasma cells	411	(1)
Different antibodies share a common structure	411	(1)
There are five classes of immuno-globulins	412	(1)
Monoclonal antibodies have many uses	413	(1)
What Is the Cellular Immune Response?	414	(4)
T cell receptors are found on two types of T cells	414	(1)
The MHC encodes proteins that present antigens to the immune system	415	(2)
Helper T cells and MHC II proteins contribute to the humoral immune response	417	(1)
Cytotoxic T cells and MHC I proteins contribute to the cellular immune response	417	(1)
MHC proteins underlie the tolerance of self	417	(1)
How Do Animals Make So Many Different Antibodies?	418	(2)
Antibody diversity results from DNA rearrangement and other mutations	418	(1)
The constant region is involved in class switching	419	(1)
What Happens When the Immune System Malfunctions?	420	(6)
Allergic reactions result from hypersensitivity	420	(1)
Autoimmune diseases are caused by reactions against self antigens	421	(1)
AIDS is an immune deficiency disorder	421	(5)
Differential Gene Expression in Development	426	(22)
What Are the Processes of Development?	427	(2)
Development proceeds via determination, differentiation, morphogenesis, and growth	427	(1)
Cell fates become more and more restricted	428	(1)
Is Cell Differentiation Irreversible?	429	(6)
Plant cells are usually totipotent	429	(1)
Among animals, the cells of early embryos are totipotent	430	(1)
The somatic cells of adult animals retain the complete genome	431	(1)
Pluripotent stem cells can be induced to differentiate by environmental signals	432	(1)
Embryonic stem cells are potentially powerful therapeutic agents	433	(2)
What Is the Role of Gene Expression in Cell Differentiation?	435	(1)
Differential gene transcription is a hallmark of cell differentiation	435	(1)
Tools of molecular biology are used to investigate development	435	(1)
How Is Cell Fate Determined?	436	(3)
Cytoplasmic segregation can determine polarity and cell fate	436	(1)
Inducers passing from one cell to another can determine cell fates	437	(2)
How Does Gene Expression Determine Pattern Formation?	439	(9)
Some genes determine programmed cell death during development	439	(1)
Plants have organ identity genes	440	(1)
Morphogen gradients provide positional information	441	(1)
In the fruit fly, a cascade of transcription factors establishes body segmentation	442	(3)
Homeobox-containing genes encode transcription factors	445	(3)
Development and Evolutionary Change	448	(16)
How Does a Molecular Tool Kit Govern Development?	449	(2)
Developmental genes in diverse organisms are similar, but have different results	449	(2)
How Can Mutations with Large Effects Change Only One Part of the Body?	451	(2)
Genetic switches govern how the molecular tool kit is used	451	(1)
Modularity allows differences in the timing and spatial pattern of gene expression	451	(2)
How Can Differences among Species Evolve?	453	(1)
How Does the Environment Modulate Development?	454	(3)
Organisms respond to signals that accurately predict the future	454	(2)
Some signals that accurately predict the future may not always occur	456	(1)
Organisms do not respond to signals that are poorly correlated with future conditions	456	(1)
Organisms may lack appropriate responses to new environmental signals	457	(1)
How Do Developmental Genes Constrain Evolution?	457	(7)
Evolution proceeds by changing what's already there	457	(1)
Conserved developmental genes can lead to parallel evolution	458	(6)
Part Five The Patterns and Processes of Evolution
The History of Life on Earth	464	(22)
How Do Scientists Date Ancient Events?	465	(3)
Readioisotopes provide a way to date rocks	466	(1)
Radioisotope dating methods have been expanded and refined	467	(1)
How Have Earth's Continents and Climates Changed over Time?	468	(3)
Oxygen has steadily increased in Earth's atmosphere	468	(2)
Earth's climate has shifted between hot/humid and cold/dry conditions	470	(1)
Volcanoes have occasionally changed the history of life	471	(1)
Extraterrestrial events have triggered changes on Earth	471	(1)
What Are the Major Events in Life's History?	471	(8)
Several processes contribute to the paucity of fossils	472	(1)
Precambrian life was small and aquatic	472	(1)
Life expanded rapidly during the Cambrian period	472	(1)
Many groups of organisms diversified	473	(3)
Geographic differentiation increased during the Mesozoic era	476	(1)
The modern biota evolved during the Cenozoic era	477	(2)
Three major faunas have dominated life on Earth	479	(1)
Why Do Evolutionary Rates Differ among Groups of Organisms?	479	(7)
``Living fossils'' exist today	479	(1)
Evolutionary changes have been gradual in most groups	479	(1)
Rates of evolutionary change are sometimes rapid	480	(1)
Rates of extinction have also varied greatly	480	(6)
The Mechanisms of Evolution	486	(22)
What Facts Form the Base of Our Understanding of Evolution?	487	(7)
Adaptation has two meanings	489	(1)
Population genetics provides an underpinning for Darwin's theory	489	(1)
Most populations are genetically variable	490	(1)
Evolutionary change can be measured by allele and genotype frequencies	491	(1)
The genetic structure of a population does not change over time if certain conditions exist	492	(1)
Deviations from Hardy--Weinberg equilibrium show that evolution is occurring	493	(1)
What Are the Mechanisms of Evolutionary Change?	494	(3)
Mutations generate genetic variation	494	(1)
Gene flow may change allele frequencies	494	(1)
Genetic drift may cause large changes in small populations	494	(1)
Nonrandom mating changes genotype frequencies	495	(2)
What Evolutionary Mechanisms Result in Adaptation?	497	(4)
Natural selection produces variable results	497	(1)
Sexual selection influences reproductive success	498	(3)
How Is Genetic Variation Maintained within Populations?	501	(2)
Neutral mutations may accumulate within populations	501	(1)
Sexual recombination amplifies the number of possible genotypes	501	(1)
Frequency-dependent selection maintains genetic variation within populations	501	(1)
Environmental variation favors genetic variation	502	(1)
Much genetic variation is maintained in geographically distinct subpopulations	503	(1)
What Are the Constraints on Evolution?	503	(2)
Developmental processes constrain evolution	504	(1)
Trade-offs constrain evolution	504	(1)
Short-term and long-term evolutionary outcomes sometimes differ	504	(1)
How Have Humans Influenced Evolution?	505	(3)
Species and Their Formation	508	(16)
What Are Species?	509	(2)
We can recognize and identify many species by their appearance	509	(1)
Species form over time	510	(1)
How Do New Species Arise?	511	(4)
Allopatric speciation requires almost complete genetic isolation	511	(2)
Sympatric speciation occurs without physical barriers	513	(2)
What Happens when Newly Formed Species Come Together?	515	(3)
Prezygotic barriers operate before fertilization	515	(1)
Postzygotic barriers operate after fertilization	516	(1)
Hybrid zones may form if reproductive isolation is incomplete	517	(1)
Why Do Rates of Speciation Vary?	518	(2)
Why Do Adaptive Radiations Occur?	520	(4)
The Evolution of Genes and Genomes	524	(18)
What Can Genomes Reveal about Evolution?	525	(5)
Evolution of genomes results in biological diversity	525	(1)
Genes and proteins are compared through sequence alignment	526	(1)
Models of sequence evolution are used to calculate evolutionary divergence	527	(1)
Experimental studies examine molecular evolution directly	527	(3)
What Are the Mechanisms of Molecular Evolution?	530	(6)
Much of evolution is neutral	531	(1)
Positive and stabilizing selection can be detected in the genome	532	(1)
Genome size and organization also evolve	533	(1)
New functions can arise by gene duplication	534	(1)
Some gene families evolve through concerted evolution	535	(1)
What Are Some Applications of Molecular Evolution?	536	(6)
Molecular sequence data are used to determine the evolutionary history of genes	537	(1)
Gene evolution is used to study protein function	538	(1)
In vitro evolution produces new molecules	538	(1)
Molecular evolution is used to study and combat diseases	538	(4)
Reconstructing and Using Phylogenies	542	(18)
What Is Phylogeny?	543	(2)
All of life is connected through evolutionary history	544	(1)
Comparisons among species require an evolutionary perspective	544	(1)
How Are Phylogenetic Trees Constructed?	545	(6)
Parsimony provides the simplest explanation for phylogenetic data	546	(1)
Phylogenies are reconstructed from many sources of data	547	(1)
Mathematical models expand the power of phylogenetic reconstruction	548	(1)
The accuracy of phylogenetic methods can be tested	549	(1)
Ancestral states can be reconstructed	550	(1)
Molecular clocks add a dimension of time	551	(1)
How Do Biologists Use Phylogenetic Trees?	551	(3)
Phylogenies help us reconstruct the past	551	(1)
Phylogenies allow us to compare and contrast living organisms	552	(1)
Biologists use phylogenies to predict the future	553	(1)
How Does Phylogeny Relate to Classification?	554	(6)
Phylogeny is the basis for modern biological classification	555	(1)
Several codes of biological nomenclature govern the use of scientific names	555	(5)
Part Six The Evolution of Diversity
Bacteria and Archaea: The Prokaryotic Domains	560	(22)
How Did the Living World Begin to Diversify?	561	(2)
The three domains differ in significant ways	561	(2)
Where Are Prokaryotes Found?	563	(2)
Prokaryotes generally form complex communities	563	(2)
What Are Some Keys to the Success of Prokaryotes?	565	(4)
Prokaryotes have distinctive cell walls	565	(1)
Prokaryotes have distinctive modes of locomotion	566	(1)
Prokaryotes reproduce asexually, but genetic recombination can occur	566	(1)
Some prokaryotes communicate	566	(1)
Prokaryotes have amazingly diverse metabolic pathways	567	(2)
How Can We Determine Prokaryote Phylogeny?	569	(2)
Size complicates the study of prokaryote phylogeny	569	(1)
The nucleotide sequences of prokaryotes reveal their evolutionary relationships	569	(1)
Lateral gene transfer may complicate phylogenetic studies	570	(1)
The great majority of prokaryote species have never been studied	570	(1)
Mutations are a major source of prokaryotic variation	571	(1)
What Are the Major Known Groups of Prokaryotes?	571	(7)
Spirochetes move by means of axial filaments	571	(1)
Chlamydias are extremely small parasites	572	(1)
Some high-GC Gram-positives are valuable sources of antibiotics	572	(1)
Cyanobacteria are important photoautotrophs	573	(1)
Not all low-GC Gram-positives are Gram-positive	573	(1)
The Proteobacteria are a large and diverse group	574	(1)
Archaea differ in several important ways from bacteria	575	(1)
Many Crenarchaeota live in hot, acidic places	576	(1)
The Euryarchaeota live in many surprising places	577	(1)
Korarchaeota and Nanoarchaeota are less well known	577	(1)
How Do Prokaryotes Affect Their Environments?	578	(4)
Prokaryotes are important players in element cycling	578	(1)
Prokaryotes live on and in other organisms	579	(1)
A small minority of bacteria are pathogens	579	(3)
The Origin and Diversification of the Eukaryotes	582	(28)
How Do Microbial Eukaryotes Affect the World Around Them?	583	(5)
The phylogeny and morphology of the microbial eukaryotes both illustrate their diversity	583	(1)
Phytoplankton are the primary producers of the marine food web	584	(1)
Some microbial eukaryotes are endosymbionts	585	(1)
Some microbial eukaryotes are deadly	585	(1)
We continue to rely on the products of ancient marine microbial eukaryotes	586	(2)
How Did the Eukaryotic Cel Arise?	588	(3)
The modern eukaryotic cell arose in several steps	588	(1)
Chloroplasts are a study in endosymbiosis	589	(1)
We cannot yet account for the presence of some prokaryotic genes in eukaryotes	590	(1)
How Did the Microbial Eukaryotes Diversify?	591	(2)
Microbial eukaryotes have different lifestyles	591	(1)
Microbial eukaryotes have diverse means of locomotion	591	(1)
Microbial eukaryotes employ vacuoles in several ways	591	(1)
The cell surfaces of microbial eukaryotes are diverse	592	(1)
How Do Microbial Eukaryotes Reproduce?	593	(3)
Some microbial eukaryotes have reproduction without sex, and sex without reproduction	593	(1)
Many microbial eukaryote life cycles feature alternation of generations	593	(1)
Chlorophytes provide examples of several life cycles	594	(1)
The life cycles of some microbial eukaryotes require more than one host species	595	(1)
What Are the Major Groups of Eukaryotes?	596	(14)
Alveolates have sacs under their plasma membrane	596	(2)
Stramenopiles have two unequal flagella, one with hairs	598	(3)
Red algae have a distinctive accessory photosynthetic pigment	601	(1)
Chlorophytes, charophytes, and land plants contain chlorophylls a and b	602	(1)
Diplomonads and parabasalids are excavates that lack mitochondria	603	(1)
Heteroloboseans alternate between amoeboid forms and forms with flagella	603	(1)
Euglenids and kinetoplastids have distinctive mitochondria and flagella	603	(1)
Foraminiferans have created vast limestone deposits	604	(1)
Radiolarians have thin, stiff pseudopods	605	(1)
Amoebozoans use lobe-shaped pseudopods for locomotion	605	(5)
Plants without Seeds: From Sea to Land	610	(20)
How Did the Land Plants Arise?	611	(2)
There are ten major groups of land plants	611	(1)
The land plants arose from a green algal clade	612	(1)
How Did Plants Colonize and Thrive on Land?	613	(3)
Adaptations to life on land distinguish land plants from green algae	613	(1)
The nonvascular plants usually live where water is available	614	(1)
Life cycles of land plants feature alternation of generations	614	(2)
The sporophytes of nonvascular plants are dependent on gametophytes	616	(1)
What Features Distinguish the Vascular Plants?	616	(6)
Vascular tissues transport water and dissolved materials	617	(1)
Vascular plants have been evolving for almost half a billion years	618	(1)
The earliest vascular plants lacked roots and leaves	619	(1)
The vascular plants branched out	619	(1)
Roots may have evolved from branches	619	(1)
Pteridophytes and seed plants have true leaves	620	(1)
Heterospory appeared among the vascular plants	621	(1)
What Are the Major Clades of Seedless Plants?	622	(8)
Liverworts may be the most ancient surviving plant clade	622	(1)
Hornworts have stomata, distinctive chloroplasts, and sporophytes without stalks	622	(1)
Water and sugar transport mechanisms emerged in the mosses	623	(1)
Some vascular plants have vascular tissue but not seeds	624	(1)
The club mosses are sister to the other vascular plants	624	(1)
Horsetails, whisk ferns, and ferns constitute a clade	625	(5)
The Evolution of Seed Plants	630	(20)
How Did Seed Plants Become Today's Dominant Vegetation?	631	(3)
Features of the seed plant life cycle protect gametes and embryos	631	(2)
The seed is a complex, well-protected package	633	(1)
A change in anatomy enabled seed plants to grow to great heights	634	(1)
What Are the Major Groups of Gymnosperms?	634	(4)
The relationship between gnetophytes and confiers is a subject of continuing research	635	(1)
Conifers have cones but no motile gametes	636	(2)
What Features Distinguish the Angiosperms?	638	(7)
The sexual structures of angiosperms are flowers	638	(2)
Flower structure has evolved over time	640	(1)
Angiosperms have coevolved with animals	641	(1)
The angiosperm life cycle features double fertilization	642	(1)
Angiosperms produce fruits	643	(2)
How Did the Angiosperms Originate and Diversify?	645	(2)
The basal angiosperm clade is a matter of controversy	645	(1)
The origin of the angiosperms remains a mystery	646	(1)
How Do Plants Support Our World?	647	(3)
Seed plants are our primary food source	647	(1)
Seed plants have been sources of medicines since ancient times	647	(3)
Fungi: Recyclers, Pathogens, Parasites, and Plant Partners	650	(20)
How Do Fungi Thrive in Virtually Every Environment?	651	(4)
The body of a multicellular fungus is composed of hyphae	651	(1)
Fungi are in intimate contact with their environment	652	(1)
Fungi exploit many nutrient sources	653	(1)
Fungi balance nutrition and reproduction	654	(1)
How Are Fungi Beneficial to Other Organisms?	655	(4)
Saprobic fungi dispose of Earth's garbage and contribute to the planetary carbon cycle	655	(1)
Mutualistic relationships are beneficial to both partners	655	(1)
Lichens can grow where plants cannot	655	(2)
Mycorrhizae are essential to most plants	657	(1)
Endophytic fungi protect some plants from pathogens, herbivores, and stress	658	(1)
Some fungi are food for the ants that farm them	658	(1)
How Do Fungal Life Cycles Differ from One Another?	659	(4)
Fungi reproduce both sexually and asexually	659	(3)
The dikaryotic condition is unique to the fungi	662	(1)
The life cycles of some parasitic fungi require two hosts	662	(1)
``Imperfect fungi'' lack a sexual stage	663	(1)
How Do We Tell the Fungal Groups Apart?	663	(7)
Chytrids are the only fungi with flagella	663	(1)
Zygomycetes reproduce sexually by fusion of two gametangia	664	(1)
Glomeromycetes form arbuscular mycorrhizae	665	(1)
The sexual reproductive structure of ascomycetes is the ascus	665	(2)
The sexual reproductive structure of basidiomycetes is a basidium	667	(3)
Animal Origins and the Evolution of Body Plans	670	(20)
What Evidence Indicates the Animals Are Monophyletic?	671	(3)
Animal monophyly is supported by gene sequences and morphology	671	(1)
Developmental patterns show evolutionary relationships among animals	672	(2)
What Are the Features of Animal Body Plans?	674	(2)
Most animals are symmetrical	674	(1)
The structure of the body cavity influences movement	674	(1)
Segmentation improves control of movement	675	(1)
Appendages enhance locomotion	676	(1)
How Do Animals Get Their Food?	676	(3)
Filter feeders capture small prey	676	(1)
Herbivores eat plants	677	(1)
Predators capture and subdue large prey	678	(1)
Parasites live in or on other organisms	679	(1)
How Do Animal Life Cycles Differ?	679	(3)
All life cycles have at least one dispersal stage	680	(1)
No life cycle can maximize all benefits	680	(1)
Parasite life cycles evolve to facilitate dispersal and overcome host defenses	681	(1)
What Are the Major Groups of Animals?	682	(8)
Sponges are loosely organized animals	683	(1)
Ctenophores are radially symmetrical and diploblastic	684	(1)
Cnidarians are specialized carnivores	685	(5)
Protostome Animals	690	(26)
What Is a Protostome?	691	(4)
Trochophores, lophophores, and spiral cleavage evolved among the lophotrochozoans	692	(1)
Ecdysozoans must shed their exoskeletons	693	(1)
Arrow worms retain some ancestral developmental features	694	(1)
What Are the Major Groups of Lophotrochozoans?	695	(7)
Ectoprocts live in colonies	695	(1)
Flatworms, rotifers, and ribbon worms are structurally diverse relatives	695	(2)
Phoronids and brachiopods use lophophores to extract food from the water	697	(1)
The annelids and the mollusks are sister groups	698	(1)
Annelids have segmented bodies	698	(2)
Mollusks have undergone a dramatic evolutionary radiation	700	(2)
What Are the Major Groups of Ecdysozoans?	702	(3)
Several marine groups have relatively few species	702	(1)
Nematodes and their relatives are abundant and diverse	703	(2)
Why Do Arthropods Dominate Earth's Fauna?	705	(11)
Arthropod relatives have fleshy, unjointed appendages	705	(1)
Jointed legs first appeared in the trilobites	706	(1)
Crustaceans are diverse and abundant	706	(2)
Insects are the dominant terrestrial arthropods	708	(4)
Myriapods have many legs	712	(1)
Most chelicerates have four pairs of legs	712	(2)
An Overview of Protostome Evolution	714	(2)
Deuterostome Animals	716	(28)
What is a Deuterostome?	717	(1)
What Are the Major Groups of Echinoderms and Hemichordates?	718	(4)
Echinoderms have a water vascular system	719	(2)
Hemichordates have a three-part body plan	721	(1)
What New Features Evolved in the Chordates?	722	(6)
Adults of most urochordates and cephalochordates are sessile	722	(1)
A new dorsal supporting structure replaces the notochord in vertebrates	723	(1)
The vertebrate body plan can support large animals	724	(1)
Fins and swim bladders improved stability and control over locomotion	725	(3)
How Did Vertebrates Colonize the Land?	728	(9)
Jointed fins enhanced support for fishes	728	(1)
Amphibians adapted to life on land	728	(2)
Amniotes colonized dry environments	730	(1)
Reptiles adapted to life in many habitat	731	(1)
Crocodilians and birds share their ancestry with the dinosaurs	731	(2)
The evolution of feathers allowed birds to fly	733	(1)
Mammals radiated after the extinction of dinosaurs	734	(1)
Most mammals are therians	735	(2)
What Traits Characterize the Primates?	737	(7)
Human ancestors evolved bipedal locomotion	738	(2)
Human brains became larger as jaws became smaller	740	(1)
Humans developed complex language and culture	741	(3)
Part Seven Flowering Plants: Form and Function
The Plant Body	744	(20)
How Is the Plant Body Organized?	745	(4)
Roots anchor the plant and take up water and minerals	746	(1)
Stems bear buds, leaves, and flowers	746	(1)
Leaves are the primary sites of photosynthesis	747	(1)
The tissue systems support the plant's activities	748	(1)
How Are Plant Cells Unique?	749	(3)
Cell walls may be complex in structure	749	(1)
Parenchyma cells are alive when they perform their functions	749	(1)
Collenchyma cells provide flexible support while alive	750	(1)
Sclerenchyma cells provide rigid support	750	(1)
Cells of the xylem transport water and minerals from roots to stems and leaves	750	(2)
Cells of the phloem translocate carbohydrates and other nutrients	752	(1)
How Do Meristems Build the Plant Body?	752	(8)
Plants and animals grow differently	753	(1)
A hierarchy of meristems generates a plant's body	754	(1)
The root apical meristem gives rise to the root cap and the root primary meristems	755	(1)
The products of the root's primary meristems become root tissues	756	(1)
The products of the stem's primary meristems become stem tissues	757	(1)
Many eudicot stems and roots undergo secondary growth	758	(2)
How Does Leaf Anatomy Support Photosynthesis?	760	(4)
Transport in Plants	764	(16)
How Do Plants Take Up Water and Solutes?	765	(4)
Water moves through a membrane by osmosis	765	(2)
Aquaporins facilitate the movement of water across membranes	767	(1)
Uptake of mineral ions requires membrane transport proteins	767	(1)
Water and ions pass to the xylem by way of the apoplast and symplast	768	(1)
How Are Water and Minerals Transported in the Xylem?	769	(4)
Experiments ruled out xylem transport by the pumping action of living cells	769	(1)
Root pressure does not account for xylem transport	770	(1)
The transpiration--cohesion--tension mechanism accounts for xylem transport	770	(1)
A pressure chamber measures tension in the xylem sap	771	(2)
How Do Stomata Control the Loss of Water and the Uptake of Co2?	773	(2)
The guard cells control the size of the stomatal opening	773	(1)
Transpiration from crops can be decreased	774	(1)
How Are Substances Translocated in the Phloem?	775	(5)
The pressure flow model appears to account for translocation in the phloem	776	(1)
The pressure flow model has been experimentally tested	776	(1)
Plasmodesmata allow the transfer of material between cells	777	(3)
Plant Nutrition	780	(16)
How Do Plants Acquire Nutrients?	781	(1)
Autotrophs make their own organic compounds	781	(1)
How does a stationary organism find nutrients?	782	(1)
What Mineral Nutrients Do Plants Require?	782	(3)
Deficiency symptoms reveal inadequate nutrition	783	(1)
Several essential elements fulfill multiple roles	784	(1)
Experiments were designed to identify essential elements	784	(1)
What Are the Roles of Soil?	785	(3)
Soils are complex in structure	785	(1)
Soils form through the weathering of rock	786	(1)
Soils are the source of plant nutrition	786	(1)
Fertilizers and lime are used in agriculture	787	(1)
Plants affect soil fertility and pH	787	(1)
How Does Nitrogen Get from Air to Plant Cells?	788	(4)
Nitrogen fixers make all other life possible	788	(1)
Nitrogenase catalyzes nitrogen fixation	789	(1)
Some plants and bacteria work together to fix nitrogen	789	(1)
Biological nitrogen fixation does not always meet agricultural needs	789	(1)
Plants and bacteria participate in the global nitrogen cycle	790	(2)
Do Soil, Air, and Sunlight Meet the Needs of All Plants?	792	(4)
Carnivorous plants supplement their mineral nutrition	792	(1)
Parasitic plants take advantage of other plants	792	(4)
Regulation of Plant Growth	796	(22)
How Does Plant Development Proceed?	797	(4)
Several hormones and photoreceptors play roles in plant growth regulation	797	(1)
Signal transduction pathways are involved in all stages of plant development	798	(1)
The seed germinates and forms a growing seedling	798	(1)
The plant flowers and sets fruit	798	(1)
The plant senesces and dies	798	(1)
Not all seeds germinate without cues	799	(1)
Seed dormancy affords adaptive advantages	799	(1)
Seed germination begins with the uptake of water	800	(1)
The embryo must mobilize its reserves	800	(1)
What Do Gibberellins Do?	801	(2)
``Foolish seedling'' disease led to the discovery of the gibberellins	801	(1)
The gibberellins have many effects on plant growth and development	802	(1)
What Does Auxin Do?	803	(6)
Phototropism led to the discovery of auxin	803	(1)
Auxin transport is polar and requires carrier proteins	803	(2)
Light and gravity affect the direction of plant growth	805	(1)
Auxin affects plant growth in several ways	805	(2)
Auxin analogs as herbicides	807	(1)
Auxin promotes growth by acting on cell walls	807	(1)
Auxin and gibberellins are recognized by similar mechanisms	808	(1)
What Do Cytokinins, Ethylene, Abscisic Acid, and Brassino-steroids Do?	809	(3)
Cytokinins are active from seed to senescence	809	(1)
Ethylene is a gaseous hormone that hastens leaf senescence and fruit ripening	810	(1)
Abscisic acid is the ``stress hormone''	811	(1)
Brassinosteroids are hormones that mediate effects of light	811	(1)
How Do Photoreceptors Participate in Plant Growth Regulation?	812	(6)
Phytochromes mediate the effects of red and far-red light	812	(1)
Phytochromes have many effects on plant growth and development	813	(1)
Multiple phytochromes have different developmental roles	813	(1)
Cryptochromes, phototropins, and zeaxanthin are blue-light receptors	814	(4)
Reproduction in Flowering Plants	818	(18)
How Do Angiosperms Reproduce Sexually?	819	(6)
The flower is an angiosperm's structure for sexual reproduction	820	(1)
Flowering plants have microscopic gametophytes	821	(1)
Pollination enables fertilization in the absence of water	821	(1)
Some flowering plants practice ``mate selection''	822	(1)
A pollen tube delivers sperm cells to the embryo sac	822	(1)
Angiosperms perform double fertilization	822	(1)
Embryos develop within seeds	823	(1)
Some fruits assist in seed dispersal	824	(1)
What Determines the Transition from the Vegetative to the Flowering State?	825	(7)
Apical meristems can become inflorescence meristems	825	(1)
A cascade of gene expression leads to flowering	825	(1)
Photoperiodic cues can initiate flowering	826	(1)
Plants vary in their responses to different photoperiodic cues	826	(1)
The length of the night is the key photoperiodic cue determining flowering	827	(1)
Circadian rhythms are maintained by a biological clock	828	(1)
Photoreceptors set the biological clock	829	(1)
The flowering stimulus originates in a leaf	829	(2)
In some plants flowering requires a period of low temperature	831	(1)
How Do Angiosperms Reproduce Asexually?	832	(4)
Many forms of asexual reproduction exist	832	(1)
Vegetative reproduction has a disadvantage	833	(1)
Vegetative reproduction is important in agriculture	833	(3)
Plant Responses to Environmental Challenges	836	(18)
How Do Plants Deal with Pathogens?	837	(3)
Plants seal off infected parts to limit damage	837	(1)
Some plants have potent chemical defenses against pathogens	838	(1)
The hypersensitive response is a localized containment strategy	838	(1)
Systemic acquired resistance is a form of long-term ``immunity''	839	(1)
Some plant genes match up with pathogen genes	839	(1)
Plants develop specific immunity to RNA viruses	840	(1)
How Do Plants Deal with Herbivores?	840	(5)
Grazing increases the productivity of some plants	840	(1)
Some plants produce chemical defenses against herbivores	841	(1)
Some secondary metabolites play multiple roles	841	(1)
Some plants call for help	842	(1)
Many defenses depend on extensive signaling	842	(1)
Recombinant DNA technology may confer resistance to insects	842	(2)
Why don't plants poison themselves?	844	(1)
The plant doesn't always win	844	(1)
How Do Plants Deal with Climate Extremes?	845	(3)
Some leaves have special adaptations to dry environments	845	(1)
Plants have other adaptations to a limited water supply	846	(1)
In water-saturated soils, oxygen is scarce	846	(1)
Plants have ways of coping with temperature extremes	847	(1)
How Do Plants Deal with Salt and Heavy Metals?	848	(6)
Most halophytes accumulate salt	848	(1)
Halophytes and xerophytes have some similar adaptations	848	(1)
Some habitats are laden with heavy metals	849	(5)
Part Eight Animals: Form and Function
Physiology, Homeostasis, and Temperature Regulation	854	(20)
Why Must Animals Regulate Their Internal Environments?	855	(5)
An internal environment makes complex multicellular animals possible	855	(1)
Homeostasis requires physiological regulation	856	(1)
Physiological systems are made up of cells, tissues, and organs	857	(2)
Organs consist of multiple tissues	859	(1)
How Does Temperature Affect Living Systems?	860	(1)
Q10 is a measure of temperature sensitivity	860	(1)
Animals can acclimatize to a seasonal temperature change	861	(1)
How Do Animals Alter Their Heat Exchange with the Environment?	861	(5)
How do endotherms produce so much heat?	861	(1)
Ectotherms and endotherms respond differently to changes in temperature	862	(1)
Energy budgets reflect adaptations for regulating body temperature	863	(1)
Both ectotherms and endotherms control blood flow to the skin	864	(1)
Some fish elevate body temperature by conserving metabolic heat	864	(1)
Some ectotherms regulate heat production	865	(1)
How Do Mammals Regulate Their Body Temperatures?	866	(8)
Basal metabolic rates are correlated with body size and environmental temperature	866	(1)
Endotherms respond to cold by producing heat and reducing heat loss	867	(1)
Evaporation of water can dissipate heat, but at a cost	868	(1)
The vertebrate thermostat uses feedback information	868	(1)
Fever helps the body fight infections	869	(1)
Turning down the thermostat	870	(4)
Animal hormones	874	(22)
What Are Hormones and How Do They Work?	875	(5)
Hormones can act locally or at a distance	875	(1)
Hormonal communication arose early in evolution	876	(1)
Hormones from the head control molting in in sects	876	(1)
Juvenile hormone controls development in insects	877	(1)
Hormones can be divided into three chemical groups	878	(1)
Hormone receptors are found on the cell surface or in the cell interior	878	(1)
Hormone action depends on the nature of the target cell and its receptors	879	(1)
How Do the Nervous and Endocrine Systems Interact?	880	(3)
The pituitary connects nervous and endocrine functions	880	(2)
The anterior pituitary is controlled by hypothalamic hormones	882	(1)
Negative feedback loops control hormone secretion	883	(1)
What Are the Major Mammalian Endocrine Glands and Hormones?	883	(7)
Thyroxine controls cell metabolism	883	(2)
Thyroid dysfunction causes goiter	885	(1)
Calcitonin reduces blood calcium	885	(1)
Parathyroid hormone elevates blood calcium	885	(1)
Vitamin D is really a hormone	886	(1)
PTH lowers blood phosphate levels	887	(1)
Insulin and glucagon regulate blood glucose levels	887	(1)
Somatostatin is a hormone of the brain and the gut	887	(1)
The adrenal gland is two glands in one	887	(2)
The sex steroids are produced by the gonads	889	(1)
Changes in control of sex steroid production initiate puberty	889	(1)
Melatonin is involved in biological rhythms and photoperiodicity	890	(1)
The list of hormones is long	890	(1)
How Do We Study Mechanisms of Hormone Action?	890	(6)
Hormones can be detected and measured with immunoassays	891	(1)
A hormone can act through many receptors	892	(1)
A hormone can act through different signal transduction pathways	893	(3)
Animal Reproduction	896	(24)
How Do Animals Reproduce Without Sex?	897	(2)
Budding and regeneration produce new individuals by mitosis	897	(1)
Parthenogenesis is the development of unfertilized eggs	898	(1)
How Do Animals Reproduce Sexually?	899	(7)
Gametogenesis produces eggs and sperm	899	(2)
Fertilization is the union of sperm and egg	901	(2)
Mating bring eggs and sperm together	903	(1)
A single body can function as both male and female	904	(1)
The evolution of vertebrate reproductive systems parallels the move to land	904	(1)
Reproductive systems are distinguished by where the embryo develops	905	(1)
How Do the Human Male and Female Reproductive Systems Work?	906	(7)
Male sex organs produce and deliver semen	906	(3)
Male sexual function is controlled by hormones	909	(1)
Female sex organs produce eggs, receive sperm, and nurture the embryo	909	(1)
The ovarian cycle produces a mature egg	910	(1)
The uterine cycle prepares an environment for the fertilized egg	911	(1)
Hormones control and coordinate the ovarian and uterine cycles	911	(1)
In pregnancy, hormones from the extra-embryonic membranes take over	912	(1)
Childbirth is triggered by hormonal and mechanical stimuli	912	(1)
How Can Fertility Be Controlled and Sexual Health Maintained?	913	(7)
Human sexual responses have four phases	913	(1)
Human use a variety of methods to control fertility	914	(2)
Reproductive technologies help solve problems of infertility	916	(1)
Sexual behavior transmits many disease organisms	917	(3)
Animal Development: From Genes to Organisms	920	(22)
How Does Fertilization Activate Development?	921	(5)
The sperm and the egg make different contributions to the zygote	921	(1)
Rearrangements of egg cytoplasm set the stage for determination	922	(1)
Cleavage repackages the cytoplasm	922	(1)
Cleavage in mammals is unique	923	(2)
Specific blastomeres generate specific tissues and organs	925	(1)
How Does Gastrulation Generate Multiple Tissue Layers?	926	(6)
Invagination of the vegetale pole characterizes gastrulation in the sea urchin	927	(1)
Gastrulation in the frog begins at the gray crescent	928	(1)
The dorsal lip of the blastopore organizes embryo formation	928	(1)
The molecular mechanisms of the organizer involve multiple transcription factors	929	(2)
The organizer changes its activity as it migrates from the dorsal lip	931	(1)
Reptilian and avian gastrulation is an adaptation to yolky eggs	931	(1)
Placental mammals have no yolk but retain the avian-reptilian gastrulation pattern	932	(1)
How Do Organs and Organ Systems Develop?	932	(2)
The stage is set by the dorsal lip of the blastopore	932	(1)
Body segmentation develops during neurulation	933	(1)
Hox genes control development along the anterior--posterior axis	933	(1)
What Is the Origin of the Placenta?	934	(2)
Extraembryonic membranes form with contributions from all germ layers	934	(1)
Extraembryonic membranes in mammals form the placenta	935	(1)
The extraembryonic membranes provide means of detecting genetic diseases	936	(1)
What Are the Stages of Human Development?	936	(6)
The embryo becomes a fetus in the first trimester	936	(1)
The fetus grows and matures during the second and third trimesters	937	(1)
Developmental changes continue throughout life	938	(4)
Neurons and Nervous Systems	942	(22)
What Cells Are Unique to the Nervous System?	943	(3)
Neuronal networks range in complexity	943	(1)
Neurons are the functional units of nervous systems	944	(2)
Glial cells are also important components of nervous systems	946	(1)
How Do Neurons Generate and Conduct Signals?	946	(9)
Simple electrical concepts underlie neuronal function	947	(1)
Membrane potentials can be measured with electrodes	947	(1)
Ion pumps and channels generate membrane potentials	947	(3)
Ion channels and their properties can now be studied directly	950	(1)
Gated ion channels alter membrane potential	950	(1)
Sudden changes in Na+ and K+ channels generate action potentials	951	(2)
Action potentials are conducted along axons without loss of signal	953	(1)
Action potentials can jump along axons	954	(1)
How Do Neurons Communicate with Other Cells?	955	(9)
The neuromuscular junction is a model chemical synapse	955	(1)
The arrival of an action potential causes the release of neurotransmitter	955	(1)
The postsynaptic membrane responds to neurotransmitter	956	(1)
Synapses between neurons can be excitatory or inhibitory	957	(1)
The postsynaptic cell sums excitatory and inhibitory input	957	(1)
Synapses can be fast or slow	958	(1)
Electrical synapses are fast but do not integrate information well	958	(1)
The action of a neurotransmitter depends on the receptor to which it binds	958	(1)
Glutamate receptors may be involved in learning and memory	959	(1)
To turn off responses, synapses must be cleared of neurotransmitter	960	(4)
Sensory Systems	964	(20)
How Do Sensory Cells Convert Stimuli into Action Potentials?	965	(2)
Sensory receptor proteins act on ion channels	965	(1)
Sensory transduction involves changes in membrane potentials	966	(1)
Sensation depends on which neurons receive action potentials from sensory cells	967	(1)
Many receptors adapt to repeated stimulation	967	(1)
How Do Sensory Systems Detect Chemical Stimuli?	967	(3)
Arthropods provide good examples for studying chemoreception	968	(1)
Olfaction is the sense of smell	968	(1)
The vomeronasal organ senses pheromones	969	(1)
Gustation is the sense of taste	969	(1)
How Do Sensory Systems Detect Mechanical Forces?	970	(6)
Many different cells respond to touch and pressure	970	(1)
Mechanoreceptors are found in muscles, tendons, and ligaments	971	(1)
Auditory systems use hair cells to sense sound waves	972	(2)
Hair cells provide information about displacement	974	(2)
How Do Sensory Systems Detect Light?	976	(8)
Rhodopsins are responsible for photosensitivity	976	(1)
Invertebrates have a variety of visual systems	977	(1)
Image-forming eyes evolved independently in vertebrates and cephalopods	978	(2)
The vertebrate retina receives and processes visual information	980	(4)
The Mammalian Nervous System: Structure and Higher Function	984	(20)
How Is the Mammalian Nervous System Organized?	985	(7)
A functional organization of the nervous system is based on flow and type of information	985	(1)
The vertebrate CNS develops from the embryonic neural tube	986	(1)
The spinal cord transmits and processes information	987	(1)
The reticular system alerts the forebrain	988	(1)
The core of the forebrain controls physiological drives, instincts, and emotions	988	(1)
Regions of the telencephalon interact to produce consciousness and control behavior	989	(3)
How Is Information Processed by Neuronal Networks?	992	(5)
The autonomic nervous system controls involuntary physiological functions	992	(1)
Patterns of light falling on the retina are integrated by the visual cortex	992	(4)
Cortical cells receive input from both eyes	996	(1)
Can Higher Functions Be Understood in Cellular Terms?	997	(7)
Sleep and dreaming are reflected in electrical patterns in the cerebral cortex	997	(2)
Some learning and memory can be localized to specific brain areas	999	(1)
Language abilities are localized in the left cerebral hemisphere	1000	(1)
What is consciousness?	1001	(3)
Effectors: How Animals Get Things Done	1004	(20)
How Do Muscles Contract?	1005	(8)
Sliding filaments cause skeletal muscle to contract	1005	(2)
Actin--myosin interactions cause filaments to slide	1007	(1)
Actin--myosin interactions are controlled by calcium ions	1008	(2)
Cardiac muscle causes the heart to beat	1010	(1)
Smooth muscle causes slow contractions of many internal organs	1010	(2)
Single skeletal muscle twitches are summed into graded contractions	1012	(1)
What Determines Muscle Strength and Endurance?	1013	(3)
Muscle fiber types determine endurance and strength	1013	(1)
A muscle has an optimal length for generating maximum tension	1014	(1)
Exercise increases muscle strength and endurance	1014	(1)
Muscle ATP supply limits performance	1014	(2)
What Roles Do Skeletal Systems Play in Movement?	1016	(4)
A hydrostatic skeleton consists of fluid in a muscular cavity	1016	(1)
Exoskeletons are rigid outer structures	1016	(1)
Vertebrate endoskeletons provide supports for muscles	1017	(1)
Bones develop from connective tissues	1018	(1)
Bones that have a common joint can work as a lever	1019	(1)
What Are Some Other Kinds of Effectors?	1020	(4)
Chromatophores allow an animal to change its color or pattern	1020	(1)
Glands secrete chemicals for defense, communication, or predation	1021	(1)
Electric organs generate electricity used for sensing, communication, defense, or attack	1021	(1)
Light-emitting organs use enzymes to produce light	1021	(3)
Gas Exchange in Animals	1024	(20)
What Physical Factors Govern Respiratory Gas Exchange?	1025	(3)
Diffusion is driven by concentration differences	1025	(1)
Fick's law applies to all systems of gas exchange	1026	(1)
Air is a better respiratory medium than water	1026	(1)
High temperatures create respiratory problems for aquatic animals	1026	(1)
O2 availability decreases with altitude	1026	(1)
CO2 is lost by diffusion	1027	(1)
What Adaptations Maximize Respiratory Gas Exchange?	1028	(4)
Respiratory organs have large surface areas	1028	(1)
Transporting gases to and from the exchange surfaces optimizes partial pressure gradients	1028	(1)
Insects have airways throughout their bodies	1028	(1)
Fish gills use countercurrent flow to maximize gas exchange	1029	(1)
Birds use unidirectional ventilation to maximize gas exchange	1030	(1)
Tidal ventilation produces dead space that limits gas exchange efficiency	1031	(1)
How Do Human Lungs Work?	1032	(4)
Respiratory tract secretions aid ventilation	1034	(1)
Lungs are ventilated by pressure changes in the thoracic cavity	1034	(2)
How Does Blood Transport Respiratory Gases?	1036	(3)
Hemoglobin combines reversibly with oxygen	1036	(1)
Myoglobin holds an oxygen reserve	1037	(1)
The affinity of hemoglobin for oxygen is variable	1037	(1)
Carbon dioxide is transported as bicarbonate ions in the blood	1038	(1)
How is Breathing Regulated?	1039	(5)
Breathing is controlled in the brain stem	1039	(1)
Regulating breathing requires feedback information	1039	(5)
Circulatory Systems	1044	(24)
Why Do Animals Need a Circulatory System?	1045	(2)
Some animals do not have circulatory systems	1045	(1)
Open circulatory systems move extracellular fluid	1046	(1)
Closed circulatory systems circulate blood through a system of blood vessels	1046	(1)
How Have Vertebrate Circulatory Systems Evolved?	1047	(3)
Fish have two-chambered hearts	1047	(1)
Amphibians have three-chambered hearts	1048	(1)
Reptiles have exquisite control of pulmonary and systemic circulation	1048	(1)
Birds and mammals have fully separated pulmonary and systemic circuits	1049	(1)
How Does the Mammalian Heart Function?	1050	(5)
Blood flows from right heart to lungs to left heart to body	1050	(2)
The heartbeat originates in the cardiac muscle	1052	(1)
A conduction system coordinates the contraction of heart muscle	1053	(1)
Electrical properties of ventricular muscles sustain heart contraction	1054	(1)
The ECG records the electrical activity of the heart	1055	(1)
What Are the Properties of Blood and Blood Vessels?	1055	(6)
Red blood cells transport respiratory gases	1055	(1)
Platelets are essential for blood clotting	1056	(1)
Plasma is a complex solution	1056	(1)
Blood circulates throughout the body in a system of blood vessels	1057	(1)
Materials are exchanged in capillary beds by filtration, osmosis, and diffusion	1057	(2)
Blood flows back to the heart through veins	1059	(1)
Lymphatic vessels return interstitial fluid to the blood	1060	(1)
Vascular disease is a killer	1060	(1)
How Is the Circulatory System Controlled and Regulated?	1061	(7)
Autoregulation matches local blood flow to local need	1061	(1)
Arterial pressure is controlled and regulated by hormonal and neuronal mechanisms	1061	(2)
Cardiovascular control in diving mammals conserves oxygen	1063	(5)
Nutrition, Digestion, and Absorption	1068	(24)
What Do Animals Require from Food?	1069	(6)
Energy can be measured in calories	1069	(1)
Energy budgets reveal how animals use their resources	1070	(1)
Sources of energy can be stored in the body	1071	(1)
Food provides carbon skeletons for biosynthesis	1072	(1)
Animals need mineral elements for a variety of functions	1073	(1)
Animals must obtain vitamins from food	1073	(1)
Nutrient deficiencies result in diseases	1074	(1)
How Do Animals Ingest and Digest Food?	1075	(3)
The food of herbivores is often low in energy and hard to digest	1075	(1)
Carnivores must detect, capture, and kill prey	1075	(1)
Vertebrate species have distinctive teeth	1076	(1)
Animals digest their food extracellularly	1076	(1)
Tubular guts have an opening at each end	1077	(1)
Digestive enzymes break down complex food molecules	1077	(1)
How Does the Vertebrate Gastrointestinal System Function?	1078	(7)
The vertebrate gut consists of concentric tissue layers	1078	(1)
Mechanical activity moves food through the gut and aids digestion	1079	(1)
Chemical digestion begins in the mouth and the stomach	1080	(1)
What causes stomach ulcers?	1081	(1)
The stomach gradually releases its contents to the small intestine	1082	(1)
Most chemical digestion occurs in the small intestine	1082	(1)
Nutrients are absorbed in the small intestine	1083	(1)
Absorbed nutrients go to the liver	1084	(1)
Water and ions are absorbed in the large intestine	1084	(1)
The problem with cellulose	1084	(1)
How Is the Flow of Nutrients Controlled and Regulated?	1085	(4)
Hormones control many digestive functions	1086	(1)
The liver directs the traffic of the molecules that fuel metabolism	1086	(1)
Regulating food intake is important	1087	(2)
How Do Animals Deal with Ingested Toxins?	1089	(3)
The body cannot metabolize many synthetic toxins	1089	(1)
Some toxins are retained and concentrated	1089	(3)
Salt and Water Balance and Nitrogen Excretion	1092	(20)
What Roles Do Excretory Organs Play in Maintaining Homeostasis?	1093	(2)
Water enters or leaves cells by osmosis	1093	(1)
Excretory organs control extracellular fluid osmolarity by filtration, secretion, and reabsorption	1094	(1)
Animals can be osmoconformers or osmoregulators	1094	(1)
Animals can be ionic conformers or ionic regulators	1095	(1)
How Do Animals Excrete Toxic Wastes from Nitrogen Metabolism?	1095	(2)
Animals excrete nitrogen in a number of forms	1095	(1)
Most species produce more than one nitrogenous waste	1096	(1)
How Do Invertebrate Excretory Systems Work?	1097	(1)
The protonephridia of flatworms excrete water and conserve salts	1097	(1)
The metanephridia of annelids process coelomic fluid	1097	(1)
The Malpighian tubules of insects depend on active transport	1098	(1)
How Do Vertebrates Maintain Salt and Water Balance?	1098	(3)
Marine fishes must conserve water	1099	(1)
Terrestrial amphibians and reptiles must avoid desiccation	1099	(1)
Birds and mammals can produce highly concentrated urine	1099	(1)
The nephron is the functional unit of the vertebrate kidney	1099	(1)
Blood is filtered in the glomerulus	1100	(1)
The renal tubules convert glomerular filtrate to urine	1101	(1)
How Does the Mammalian Kidney Produce Concentrated Urine?	1101	(6)