Ebook for Biology Concepts and Investigations

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UNIT 1 Science, Chemistry, and Cells
	1 The Scientific Study of Life
		1.1 What Is Life?
			A. Life Is Organized
			B. Life Requires Energy
			C. Life Maintains Internal Constancy
			D. Life Reproduces, Grows, and Develops
			E. Life Evolves
		1.2 The Tree of Life Includes Three Main Branches
		1.3 Scientists Study the Natural World
			A. The Scientific Method Has Multiple Interrelated Parts
			B. An Experimental Design Is a Careful Plan
			C. Theories Are Comprehensive Explanations
			D. Scientific Inquiry Has Limitations
			E. Biology Continues to Advance
		1.4 Investigating Life: The Orchid and the Moth
	2 The Chemistry of Life
		2.1 Atoms Make Up All Matter
			A. Elements Are Fundamental Types of Matter
			B. Atoms Are Particles of Elements
			C. Isotopes Have Different Numbers of Neutrons
		2.2 Chemical Bonds Link Atoms
			A. Electrons Determine Bonding
			B. In an Ionic Bond, One Atom Transfers Electrons to Another Atom
			C. In a Covalent Bond, Atoms Share Electrons
			D. Partial Charges on Polar Molecules Create Hydrogen Bonds
		2.3 Water Is Essential to Life
			A. Water Is Cohesive and Adhesive
			B. Many Substances Dissolve in Water
			C. Water Regulates Temperature
			D. Water Expands As It Freezes
			E. Water Participates in Life's Chemical Reactions
		2.4 Cells Have an Optimum pH
			A. The pH Scale Expresses Acidity or Alkalinity
			B. Buffers Regulate pH
		2.5 Cells Contain Four Major Types of Organic Molecules
			A. Large Organic Molecules Are Composed of Smaller Subunits
			B. Carbohydrates Include Simple Sugars and Polysaccharides
			C. Proteins Are Complex and Highly Versatile
			D. Nucleic Acids Store and Transmit Genetic Information
			E. Lipids Are Hydrophobic and Energy-Rich
		2.6 Investigating Life: Chemical Warfare on a Tiny Battlefield
	3 Cells
		3.1 Cells Are the Units of Life
			A. Simple Lenses Revealed the First Glimpses of Cells
			B. The Cell Theory Emerges
			C. Microscopes Magnify Cell Structures
			D. All Cells Have Features in Common
		3.2 Different Cell Types Characterize Life's Three Domains
			A. Domain Bacteria Contains Earth's Most Abundant Organisms
			B. Domain Archaea Includes Prokaryotes with Unique Biochemistry
			C. Domain Eukarya Contains Organisms with Complex Cells
		3.3 A Membrane Separates Each Cell from Its Surroundings
		3.4 Eukaryotic Organelles Divide Labor
			A. The Nucleus, Endoplasmic Reticulum, and Golgi Interact to Secrete Substances
			B. Lysosomes, Vacuoles, and Peroxisomes Are Cellular Digestion Centers
			C. Mitochondria Extract Energy from Nutrients
			D. Photosynthesis Occurs in Chloroplasts
		3.5 The Cytoskeleton Supports Eukaryotic Cells
			A. Proteins Form the Cytoskeleton
			B. Cilia and Flagella Help Cells Move
		3.6 Cells Stick Together and Communicate with One Another
			A. Animal Cell Junctions Occur in Several Forms
			B. Cell Walls Are Strong, Flexible, and Porous
		3.7 Investigating Life: The Tiniest Compass
	4 The Energy of Life
		4.1 All Cells Capture and Use Energy
			A. Energy Allows Cells to Do Life's Work
			B. The Laws of Thermodynamics Describe Energy Transfer
		4.2 Networks of Chemical Reactions Sustain Life
			A. Chemical Reactions Absorb or Release Energy
			B. Linked Oxidation and Reduction Reactions Form Electron Transport Chains
		4.3 ATP Is Cellular Energy Currency
			A. Coupled Reactions Release and Store Energy in ATP
			B. ATP Represents Short-Term Energy Storage
		4.4 Enzymes Speed Biochemical Reactions
			A. Enzymes Bring Reactants Together
			B. Enzymes Have Partners
			C. Cells Control Reaction Rates
		4.5 Membrane Transport May Release Energy or Cost Energy
			A. Passive Transport Does Not Require Energy Input
			B. Active Transport Requires Energy Input
			C. Endocytosis and Exocytosis Use Vesicles to Transport Substances
		4.6 Investigating Life: Energy Efficiency in an Electric Fish
	5 Photosynthesis
		5.1 Life Depends on Photosynthesis
			A. Photosynthesis Builds Carbohydrates Out of Carbon Dioxide and Water
			B. Plants Use Carbohydrates in Many Ways
			C. The Evolution of Photosynthesis Changed Planet Earth
		5.2 Sunlight Is the Energy Source for Photosynthesis
			A. What Is Light?
			B. Photosynthetic Pigments Capture Light Energy
			C. Chloroplasts Are the Sites of Photosynthesis
		5.3 Photosynthesis Occurs in Two Stages
		5.4 The Light Reactions Begin Photosynthesis
			A. Light Striking Photosystem II Provides the Energy to Produce ATP
			B. Electrons from Photosystem I Reduce NADP[sup(+)] to NADPH
			5.5 The Carbon Reactions Produce Carbohydrates
			5.6 C3, C4, and CAM Plants Use Different Carbon Fixation Pathways
			5.7 Investigating Life: Solar-Powered Salamanders
	6 Respiration and Fermentation
		6.1 Cells Use Energy in Food to Make ATP
		6.2 Cellular Respiration Includes Three Main Processes
		6.3 In Eukaryotic Cells, Mitochondria Produce Most ATP
		6.4 Glycolysis Breaks Down Glucose to Pyruvate
		6.5 Aerobic Respiration Yields Abundant ATP
			A. Pyruvate Is Oxidized to Acetyl CoA
			B. The Krebs Cycle Produces ATP and Electron Carriers
			C. The Electron Transport Chain Drives ATP Formation
		6.6 How Many ATPs Can One Glucose Molecule Yield?
		6.7 Other Food Molecules Enter the Energy-Extracting Pathways
		6.8 Some Energy Pathways Do Not Require Oxygen
			A. Anaerobic Respiration Uses an Electron Acceptor Other Than O2
			B. Fermenters Acquire ATP Only from Glycolysis
		6.9 Photosynthesis and Respiration Are Ancient Pathways
		6.10 Investigating Life: Hot Plants Offer Heat Reward
UNIT 2 DNA, Inheritance, and Biotechnology
	7 DNA Structure and Gene Function
		7.1 Experiments Identified the Genetic Material
			A. Bacteria Can Transfer Genetic Information
			B. Hershey and Chase Confirmed the Genetic Role of DNA
		7.2 DNA Is a Double Helix of Nucleotides
		7.3 DNA Contains the "Recipes" for a Cell's Proteins
			A. Protein Synthesis Requires Transcription and Translation
			B. RNA Is an Intermediary Between DNA and a Protein
		7.4 Transcription Uses a DNA Template to Build RNA
			A. Transcription Occurs in Three Steps
			B. mRNA Is Altered in the Nucleus of Eukaryotic Cells
		7.5 Translation Builds the Protein
			A. The Genetic Code Links mRNA to Protein
			B. Translation Requires mRNA, tRNA, and Ribosomes
			C. Translation Occurs in Three Steps
			D. Proteins Must Fold Correctly After Translation
		7.6 Cells Regulate Gene Expression
			A. Operons Are Groups of Bacterial Genes That Share One Promoter
			B. Eukaryotic Organisms Use Many Regulatory Mechanisms
		7.7 Mutations Change DNA Sequences
			A. Mutations Range from Silent to Devastating
			B. What Causes Mutations?
			C. Mutations May Pass to Future Generations
			D. Mutations Are Important
		7.8 Investigating Life: Clues to the Origin of Language
	8 DNA Replication, Binary Fission, and Mitosis
		8.1 Cells Divide and Cells Die
			A. Sexual Life Cycles Include Mitosis, Meiosis, and Fertilization
			B. Cell Death Is Part of Life
		8.2 DNA Replication Precedes Cell Division
		8.3 Prokaryotes Divide by Binary Fission
		8.4 Chromosomes Condense Before Cell Division
		8.5 Mitotic Division Generates Exact Cell Copies
			A. DNA Is Copied During Interphase
			B. Chromosomes Divide During Mitosis
			C. The Cytoplasm Splits in Cytokinesis
		8.6 Cancer Arises When Cells Divide Out of Control
			A. Chemical Signals Regulate Cell Division
			B. Cancer Cells Break Through Cell Cycle Controls
			C. Cancer Cells Differ from Normal Cells in Many Ways
			D. Cancer Treatments Remove or Kill Abnormal Cells
			E. Genes and Environment Both Can Increase Cancer Risk
		8.7 Apoptosis Is Programmed Cell Death
		8.8 Investigating Life: Cutting Off a Tumor's Supply Lines in the War on Cancer
	9 Sexual Reproduction and Meiosis
		9.1 Why Sex?
		9.2 Diploid Cells Contain Two Homologous Sets of Chromosomes
		9.3 Meiosis Is Essential in Sexual Reproduction
			A. Gametes Are Haploid Sex Cells
			B. Specialized Germ Cells Undergo Meiosis
			C. Meiosis Halves the Chromosome Number and Scrambles Alleles
		9.4 In Meiosis, DNA Replicates Once, but the Nucleus Divides Twice
			A. In Meiosis I, Homologous Chromosomes Pair Up and Separate
			B. Meiosis II Yields Four Haploid Nuclei
		9.5 Meiosis Generates Enormous Variability
			A. Crossing Over Shuffles Alleles
			B. Homologous Pairs Are Oriented Randomly During Metaphase I
			C. Fertilization Multiplies the Diversity
		9.6 Mitosis and Meiosis Have Different Functions: A Summary
		9.7 Errors Sometimes Occur in Meiosis
			A. Cells May Inherit Too Many or Too Few Chromosomes
			B. Changes in Chromosome Structure May Be Harmful
		9.8 Haploid Nuclei Are Packaged into Gametes
			A. In Humans, Gametes Form in Testes and Ovaries
			B. In Plants, Gametophytes Produce Gametes
		9.9 Investigating Life: Evolving Germs Select for Sex in Worms
	10 Patterns of Inheritance
		10.1 Chromosomes Are Packets of Genetic Information: A Review
		10.2 Mendel's Experiments Uncovered Basic Laws of Inheritance
			A. Why Peas?
			B. Dominant Alleles Appear to Mask Recessive Alleles
			C. For Each Gene, a Cell's Two Alleles May Be Identical or Different
			D. Every Generation Has a Name
		10.3 The Two Alleles of a Gene End Up in Different Gametes
			A. The Simplest Punnett Squares Track the Inheritance of One Gene
			B. Meiosis Explains Mendel's Law of Segregation
		10.4 Genes on Different Chromosomes Are Inherited Independently
			A. Tracking Two-Gene Inheritance May Require Large Punnett Squares
			B. Meiosis Explains Mendel's Law of Independent Assortment
			C. The Product Rule Is a Useful Shortcut
		10.5 Genes on the Same Chromosome May Be Inherited Together
			A. Genes on the Same Chromosome Are Linked
			B. Studies of Linked Genes Have Yielded Chromosome Maps
		10.6 Dominance Relationships Are Rarely Simple
			A. Incomplete Dominance and Codominance Add Phenotype Classes
			B. Some Inheritance Patterns Are Especially Difficult to Interpret
		10.7 Sex-Linked Genes Have Unique Inheritance Patterns
			A. X and Y Chromosomes Carry Sex-Linked Genes
			B. X-Linked Recessive Disorders Affect More Males Than Females
			C. X Inactivation Prevents "Double Dosing" of Proteins
		10.8 Pedigrees Show Modes of Inheritance
		10.9 Most Traits Are Influenced by the Environment and Multiple Genes
			A. The Environment Can Alter the Phenotype
			B. Polygenic Traits Depend on More Than One Gene
		10.10 Investigating Life: Heredity and the Hungry Hordes
	11 DNA Technology
		11.1 DNA Technology Is Changing the World
		11.2 DNA Technology's Tools Apply to Individual Genes or Entire Genomes
			A. Transgenic Organisms Contain DNA from Other Species
			B. DNA Sequencing Reveals the Order of Bases
			C. PCR Replicates DNA in a Test Tube
			D. DNA Profiling Detects Genetic Differences
		11.3 Stem Cells and Cloning Add New Ways to Copy Cells and Organisms
			A. Stem Cells Divide to Form Multiple Cell Types
			B. Cloning Produces Identical Copies of an Organism
		11.4 Many Medical Tests and Procedures Use DNA Technology
			A. DNA Probes Detect Specific Sequences
			B. Preimplantation Genetic Diagnosis Can Screen Embryos for Some Diseases
			C. Genetic Testing Can Detect Existing Diseases
			D. Gene Therapy Uses DNA to Treat Disease
			E. Medical Uses of DNA Technology Raise Many Ethical Issues
		11.5 Investigating Life: Weeds Get a Boost from Their Transgenic Cousins
UNIT 3 The Evolution of Life
	12 The Forces of Evolutionary Change
		12.1 Evolution Acts on Populations
		12.2 Evolutionary Thought Has Evolved for Centuries
			A. Many Explanations Have Been Proposed for Life's Diversity
			B. Charles Darwin's Voyage Provided a Wealth of Evidence
			C. On the Origin of Species Proposed Natural Selection as an Evolutionary Mechanism
			D. Evolutionary Theory Continues to Expand
		12.3 Natural Selection Molds Evolution
			A. Adaptations Enhance Reproductive Success
			B. Natural Selection Eliminates Poorly Adapted Phenotypes
			C. Natural Selection Does Not Have a Goal
			D. What Does "Survival of the Fittest" Really Mean?
		12.4 Evolution Is Inevitable in Real Populations
			A. At Hardy–Weinberg Equilibrium, Allele Frequencies Do Not Change
			B. In Reality, Allele Frequencies Always Change
		12.5 Natural Selection Can Shape Populations in Many Ways
		12.6 Sexual Selection Directly Influences Reproductive Success
		12.7 Evolution Occurs in Several Additional Ways
			A. Mutation Fuels Evolution
			B. Genetic Drift Occurs by Chance
			C. Nonrandom Mating Concentrates Alleles Locally
			D. Gene Flow Moves Alleles Between Populations
		12.8 Investigating Life: Size Matters in Fishing Frenzy
	13 Evidence of Evolution
		13.1 Clues to Evolution Lie in the Earth, Body Structures, and Molecules
		13.2 Fossils Record Evolution
			A. Fossils Form in Many Ways
			B. The Fossil Record Is Often Incomplete
			C. The Age of a Fossil Can Be Estimated in Two Ways
		13.3 Biogeography Considers Species' Geographical Locations
			A. The Theory of Plate Tectonics Explains Earth's Shifting Continents
			B. Species Distributions Reveal Evolutionary Events
		13.4 Anatomical Comparisons May Reveal Common Descent
			A. Homologous Structures Have a Shared Evolutionary Origin
			B. Vestigial Structures Have Lost Their Functions
			C. Convergent Evolution Produces Superficial Similarities
		13.5 Embryonic Development Patterns Provide Evolutionary Clues
		13.6 Molecules Reveal Relatedness
			A. Comparing DNA and Protein Sequences May Reveal Close Relationships
			B. Molecular Clocks Help Assign Dates to Evolutionary Events
		13.7 Investigating Life: Limbs Gained and Limbs Lost
	14 Speciation and Extinction
		14.1 What Is a Species?
			A. Linnaeus Devised the Binomial Naming System
			B. Species Can Be Defined Based on the Potential to Interbreed
		14.2 Reproductive Barriers Cause Species to Diverge
			A. Prezygotic Barriers Prevent Fertilization
			B. Postzygotic Barriers Prevent the Development of Fertile Offspring
		14.3 Spatial Patterns Define Three Types of Speciation
			A. Allopatric Speciation Reflects a Geographic Barrier
			B. Parapatric Speciation Occurs in Neighboring Regions
			C. Sympatric Speciation Occurs in a Shared Habitat
			D. Determining the Type of Speciation May Be Difficult
		14.4 Speciation May Be Gradual or May Occur in Bursts
			A. Gradualism and Punctuated Equilibrium Are Two Models of Speciation
			B. Bursts of Speciation Occur During Adaptive Radiation
		14.5 Extinction Marks the End of the Line
			A. Many Factors Can Combine to Put a Species at Risk
			B. Extinction Rates Have Varied over Time
		14.6 Biological Classification Systems Are Based on Common Descent
			A. The Taxonomic Hierarchy Organizes Species into Groups
			B. A Cladistics Approach Is Based on Shared Derived Traits
			C. Cladograms Depict Hypothesized Evolutionary Relationships
			D. Many Traditional Groups Are Not Clades
		14.7 Investigating Life: Plant Protection Rackets May Stimulate Speciation
	15 The Origin and History of Life
		15.1 Life's Origin Remains Mysterious
			A. The First Organic Molecules May Have Formed in a Chemical "Soup"
			B. Some Investigators Suggest an "RNA World"
			C. Membranes Enclosed the Molecules
			D. Early Life Changed Earth Forever
		15.2 Complex Cells and Multicellularity Arose over a Billion Years Ago
			A. Endosymbiosis Explains the Origin of Mitochondria and Chloroplasts
			B. Multicellularity May Also Have Its Origin in Cooperation
		15.3 Life's Diversity Exploded in the Past 500 Million Years
			A. The Strange Ediacarans Flourished Late in the Precambrian
			B. Paleozoic Plants and Animals Emerged onto Land
			C. Reptiles and Flowering Plants Thrived During the Mesozoic Era
			D. Mammals Diversified During the Cenozoic Era
		15.4 Fossils and DNA Tell the Human Evolution Story
			A. Humans Are Primates
			B. Molecular Evidence Documents Primate Relationships
			C. Human Evolution Is Partially Recorded in Fossils
			D. Environmental Changes Have Spurred Human Evolution
			E. Migration and Culture Have Changed Homo sapiens
		15.5 Investigating Life: What Makes Us Human?
UNIT 4 The Diversity of Life
	16 Viruses
		16.1 Viruses Are Genes Wrapped in a Protein Coat
			A. Viruses Are Smaller and Simpler Than Cells
			B. A Virus's Host Range Consists of the Organisms It Infects
			C. Are Viruses Alive?
		16.2 Viral Replication Occurs in Five Stages
		16.3 Viruses May Kill Bacteria Immediately or Their DNA May "Hide" in the Cell
		16.4 Illnesses Caused by Animal Viruses May Be Mild or Severe
			A. Symptoms Result from Cell Death and the Immune Response
			B. Some Animal Viruses Linger for Years
			C. Drugs and Vaccines Help Fight Viral Infections
		16.5 Viruses Cause Diseases in Plants
		16.6 Viroids and Prions Are Other Noncellular Infectious Agents
			A. A Viroid Is an Infectious RNA Molecule
			B. A Prion Is an Infectious Protein
		16.7 Investigating Life: Scientific Detectives Follow HIV's Trail
	17 Bacteria and Archaea
		17.1 Prokaryotes Are a Biological Success Story
		17.2 Prokaryote Classification Traditionally Relies on Cell Structure and Metabolism
			A. Microscopes Reveal Cell Structures
			B. Metabolic Pathways May Be Useful in Classification
			C. Molecular Data Reveal Evolutionary Relationships
			D. Horizontal Gene Transfer Complicates Classification
		17.3 Prokaryotes Include Two Domains with Enormous Diversity
			A. Domain Bacteria Includes Many Familiar Groups
			B. Many, but Not All, Archaea Are "Extremophiles"
		17.4 Bacteria and Archaea Are Essential to All Life
			A. Microbes Form Vital Links in Ecosystems
			B. Bacteria and Archaea Live in and on Us
			C. Humans Put Many Prokaryotes to Work
		17.5 Investigating Life: Bacterial Evolution Goes "Hog Wild" on the Farm
	18 Protists
		18.1 Protists Lie at the Crossroads Between Simple and Complex Organisms
			A. What Is a Protist?
			B. Protists Are Important in Many Ways
			C. Protists Have a Lengthy Evolutionary History
		18.2 Algae Are Photosynthetic Protists
			A. Euglenoids Are Heterotrophs and Autotrophs
			B. Dinoflagellates Are "Whirling Cells"
			C. Golden Algae, Diatoms, and Brown Algae Contain Yellowish Pigments
			D. Red Algae Can Live in Deep Water
			E. Green Algae Are the Closest Relatives of Land Plants
		18.3 Some Heterotrophic Protists Resemble Fungi
			A. Slime Molds Are Unicellular and Multicellular
			B. Water Molds Are Decomposers and Parasites
		18.4 Protozoa Are Diverse Heterotrophic Protists
			A. Several Flagellated Protozoa Cause Disease
			B. Amoeboid Protozoa Produce Pseudopodia
			C. Ciliates Are Common Protozoa with Complex Cells
			D. Apicomplexans Include Nonmotile Animal Parasites
		18.5 Protist Classification Is Changing Rapidly
		18.6 Investigating Life: Shining a Spotlight on Danger
	19 Plants
		19.1 Plants Have Changed the World
			A. Green Algae Are the Closest Relatives of Plants
			B. Plants Are Adapted to Life on Land
		19.2 Bryophytes Are the Simplest Plants
			A. Bryophytes Lack Vascular Tissue
			B. Bryophytes Have a Conspicuous Gametophyte
		19.3 Seedless Vascular Plants Have Xylem and Phloem but No Seeds
			A. Seedless Vascular Plants Include Ferns and Their Close Relatives
			B. Seedless Vascular Plants Have a Conspicuous Sporophyte and Swimming Sperm
		19.4 Gymnosperms Are "Naked Seed" Plants
			A. Gymnosperms Include Conifers and Three Related Groups
			B. Conifers Produce Pollen and Seeds in Cones
		19.5 Angiosperms Produce Seeds in Fruits
			A. Most Angiosperms Are Eudicots or Monocots
			B. Flowers and Fruits Are Unique to the Angiosperm Life Cycle
			C. Wind and Animals Often Participate in Angiosperm Reproduction
		19.6 Investigating Life: Genetic Messages from Ancient Ecosystems
	20 Fungi
		20.1 Fungi Are Essential Decomposers
			A. Fungi Are Eukaryotic Heterotrophs That Digest Food Externally
			B. Fungal Classification Is Traditionally Based on Reproductive Structures
		20.2 Chytridiomycetes Produce Swimming Spores
		20.3 Zygomycetes Are Fast-Growing and Prolific
		20.4 Glomeromycetes Colonize Living Plant Roots
		20.5 Ascomycetes Are the Sac Fungi
		20.6 Basidiomycetes Are the Familiar Club Fungi
		20.7 Fungi Interact with Other Organisms
			A. Endophytes Colonize Plant Tissues
			B. Mycorrhizal Fungi Exchange Materials with Roots
			C. Some Ants Cultivate Fungi
			D. Lichens Are Dual Organisms
		20.8 Investigating Life: The Battle for Position in Cacao Tree Leaves
	21 Animals
		21.1 Animals Live Nearly Everywhere
			A. What Is an Animal?
			B. Animal Life Began in the Water
			C. Animal Features Reflect Shared Ancestry
			D. Biologists Also Consider Additional Characteristics
		21.2 Sponges Are Simple Animals That Lack Differentiated Tissues
		21.3 Cnidarians Are Radially Symmetrical, Aquatic Animals
		21.4 Flatworms Have Bilateral Symmetry and Incomplete Digestive Tracts
		21.5 Mollusks Are Soft, Unsegmented Animals
		21.6 Annelids Are Segmented Worms
		21.7 Nematodes Are Unsegmented, Cylindrical Worms
		21.8 Arthropods Have Exoskeletons and Jointed Appendages
			A. Arthropods Have Complex Organ Systems
			B. Arthropods Are the Most Diverse Animals
		21.9 Echinoderm Adults Have Five-Part, Radial Symmetry
		21.10 Most Chordates Are Vertebrates
			A. Four Key Features Distinguish Chordates
			B. Many Features Reveal Evolutionary Relationships Among Chordates
		21.11 Tunicates and Lancelets Are Invertebrate Chordates
		21.12 Hagfishes and Lampreys Are Craniates Lacking Jaws
		21.13 Fishes Are Aquatic Vertebrates with Jaws, Gills, and Fins
			A. Cartilaginous Fishes Include Sharks, Skates, and Rays
			B. Bony Fishes Include Two Main Lineages
			C. Fishes Changed the Course of Vertebrate Evolution
		21.14 Amphibians Lead a Double Life on Land and in Water
			A. Amphibians Were the First Tetrapods
			B. Amphibians Include Three Main Lineages
		21.15 Reptiles Were the First Vertebrates to Thrive on Dry Land
			A. Nonavian Reptiles Include Four Main Groups
			B. Birds Are Warm, Feathered Reptiles
		21.16 Mammals Are Warm, Furry Milk-Drinkers
			A. Mammals Share a Common Ancestor with Reptiles
			B. Mammals Lay Eggs or Bear Live Young
		21.17 Investigating Life: Sponges Fill Holes in Animal Evolution
UNIT 5 Plant Life
	22 Plant Form and Function
		22.1 Vegetative Plant Parts Include Stems, Leaves, and Roots
		22.2 Plant Cells Build Tissues
			A. Plants Have Several Cell Types
			B. Plant Cells Form Three Main Tissue Systems
		22.3 Tissues Build Stems, Leaves, and Roots
			A. Stems Support Leaves
			B. Leaves Are the Primary Organs of Photosynthesis
			C. Roots Absorb Water and Minerals and Anchor the Plant
		22.4 Plants Have Flexible Growth Patterns, Thanks to Meristems
			A. Plants Grow by Adding New Modules
			B. Plant Growth Occurs at Meristems
			C. In Primary Growth, Apical Meristems Lengthen Stems and Roots
			D. In Secondary Growth, Lateral Meristems Thicken Stems and Roots
		22.5 Investigating Life: An Army of Tiny Watchdogs
	23 Plant Nutrition and Transport
		23.1 Soil and Air Provide Water and Nutrients
			A. Plants Require 16 Essential Elements
			B. Soils Have Distinct Layers
			C. Leaves and Roots Absorb Essential Elements
		23.2 Water and Minerals Are Pulled Up to Leaves in Xylem
			A. Water Evaporates from Leaves in Transpiration
			B. Water and Dissolved Minerals Enter at the Roots
			C. Xylem Transport Relies on Cohesion
			D. The Cuticle and Stomata Help Conserve Water
		23.3 Sugars Are Pushed in Phloem to Nonphotosynthetic Cells
			A. Phloem Sap Contains Sugars and Other Organic Compounds
			B. The Pressure Flow Theory Explains Phloem Function
		23.4 Parasitic Plants Tap into Another Plant's Vascular Tissue
		23.5 Investigating Life: The Hidden Cost of Traps
	24 Reproduction and Development of Flowering Plants
		24.1 Angiosperms Reproduce Asexually and Sexually
			A. Asexual Reproduction Yields Clones
			B. Sexual Reproduction Generates Variability
		24.2 The Angiosperm Life Cycle Includes Flowers, Fruits, and Seeds
			A. Flowers Are Reproductive Organs
			B. The Pollen Grain and Embryo Sac Are Gametophytes
			C. Pollination Brings Pollen to the Stigma
			D. Double Fertilization Yields Zygote and Endosperm
			E. A Seed Is an Embryo and Its Food Supply Inside a Seed Coat
			F. The Fruit Develops from the Ovary
			G. Fruits Protect and Disperse Seeds
		24.3 Plant Growth Begins with Seed Germination
		24.4 Hormones Regulate Plant Growth and Development
			A. Auxins and Cytokinins Are Essential for Plant Growth
			B. Gibberellins, Ethylene, and Abscisic Acid Influence Plant Development in Many Ways
			C. Biologists Continue to Discover Additional Plant Hormones
		24.5 Light Is a Powerful Influence on Plant Life
			A. Phototropism Is Growth Toward Light
			B. Phytochrome Regulates Seed Germination, Daily Rhythms, and Flowering
		24.6 Plants Respond to Gravity and Touch
		24.7 Plant Parts Die or Become Dormant
		24.8 Investigating Life: A Red Hot Chili Pepper Paradox
UNIT 6 Animal Life
	25 Animal Tissues and Organ Systems
		25.1 Specialized Cells Build Animal Bodies
		25.2 Animals Consist of Four Tissue Types
			A. Epithelial Tissue Covers Surfaces
			B. Most Connective Tissues Bind Other Tissues Together
			C. Muscle Tissue Provides Movement
			D. Nervous Tissue Forms a Rapid Communication Network
		25.3 Organ Systems Are Interconnected
			A. The Nervous and Endocrine Systems Coordinate Communication
			B. The Skeletal and Muscular Systems Support and Move the Body
			C. The Digestive, Circulatory, and Respiratory Systems Help Acquire Energy
			D. The Urinary, Integumentary, Immune, and Lymphatic Systems Protect the Body
			E. The Reproductive System Produces the Next Generation
		25.4 Organ System Interactions Promote Homeostasis
		25.5 The Integumentary System Regulates Temperature and Conserves Moisture
		25.6 Investigating Life: Vitamins and the Evolution of Human Skin Pigmentation
	26 The Nervous System
		26.1 The Nervous System Forms a Rapid Communication Network
			A. Invertebrates Have Nerve Nets, Nerve Ladders, or Nerve Cords
			B. Vertebrate Nervous Systems Are Highly Centralized
		26.2 Neurons Are Functional Units of a Nervous System
			A. A Typical Neuron Consists of a Cell Body, Dendrites, and an Axon
			B. The Nervous System Includes Three Classes of Neurons
		26.3 Action Potentials Convey Messages
			A. A Neuron at Rest Has a Negative Charge
			B. A Neuron's Membrane Potential Reverses During an Action Potential
			C. The Myelin Sheath Speeds Impulse Conduction
		26.4 Neurotransmitters Pass the Message from Cell to Cell
			A. Neurons Communicate at Synapses
			B. A Neuron Integrates Signals from Multiple Synapses
		26.5 The Peripheral Nervous System Consists of Nerve Cells Outside the Central Nervous System
		26.6 The Central Nervous System Consists of the Spinal Cord and Brain
			A. The Spinal Cord Transmits Information Between Body and Brain
			B. The Human Brain Is Divided into Several Regions
			C. Many Brain Regions Participate in Memory Formation
			D. Damage to the Central Nervous System Can Be Devastating
		26.7 Investigating Life: Scorpion Stings Don't Faze Grasshopper Mice
	27 The Senses
		27.1 Diverse Senses Operate by the Same Principles
			A. Sensory Receptors Respond to Stimuli by Generating Action Potentials
			B. Continuous Stimulation May Cause Sensory Adaptation
		27.2 The General Senses Detect Touch, Temperature, Pain, and Position
		27.3 The Senses of Smell and Taste Detect Chemicals
			A. Chemoreceptors in the Nose Detect Odor Molecules
			B. Chemoreceptors in the Mouth Detect Taste
		27.4 Vision Depends on Light-Sensitive Cells
			A. Invertebrate Eyes Take Many Forms
			B. In the Vertebrate Eye, Light Is Focused on the Retina
			C. Signals Travel from the Retina to the Optic Nerve and Brain
		27.5 The Senses of Hearing and Equilibrium Begin in the Ears
			A. Mechanoreceptors in the Inner Ear Detect Sound Waves
			B. The Inner Ear Also Provides the Sense of Equilibrium
		27.6 Investigating Life: How Do Whales Taste?
	28 The Endocrine System
		28.1 The Endocrine System Uses Hormones to Communicate
			A. Endocrine Glands Secrete Hormones That Interact with Target Cells
			B. The Nervous and Endocrine Systems Work Together
		28.2 Hormones Stimulate Responses in Target Cells
			A. Water-Soluble Hormones Trigger Second Messenger Systems
			B. Lipid-Soluble Hormones Directly Alter Gene Expression
		28.3 The Hypothalamus and Pituitary Gland Oversee Endocrine Control
			A. The Posterior Pituitary Stores and Releases Two Hormones
			B. The Anterior Pituitary Produces and Secretes Six Hormones
		28.4 Hormones from Many Glands Regulate Metabolism
			A. The Thyroid Gland Sets the Metabolic Pace
			B. The Parathyroid Glands Control Calcium Level
			C. The Adrenal Glands Coordinate the Body's Stress Responses
			D. The Pancreas Regulates Blood Glucose
			E. The Pineal Gland Secretes Melatonin
		28.5 Hormones from the Ovaries and Testes Control Reproduction
		28.6 Investigating Life: Addicted to Affection
	29 The Skeletal and Muscular Systems
		29.1 Skeletons Take Many Forms
		29.2 The Vertebrate Skeleton Features a Central Backbone
		29.3 Bones Provide Support, Protect Internal Organs, and Supply Calcium
			A. Bones Consist Mostly of Bone Tissue and Cartilage
			B. Bones Are Constantly Built and Degraded
			C. Bones Help Regulate Calcium Homeostasis
			D. Bone Meets Bone at a Joint
		29.4 Muscle Movement Requires Contractile Proteins, Calcium, and ATP
			A. Actin and Myosin Filaments Fill Muscle Cells
			B. Sliding Filaments Are the Basis of Muscle Fiber Contraction
			C. Motor Neurons Stimulate Muscle Fiber Contraction
		29.5 Muscle Fibers Generate ATP in Many Ways
		29.6 Many Muscle Fibers Combine to Form One Muscle
			A. Each Muscle May Contract with Variable Force
			B. Muscles Contain Slow- and Fast-Twitch Fibers
			C. Exercise Strengthens Muscles
		29.7 Investigating Life: Did a Myosin Gene Mutation Make Humans Brainier?
	30 The Circulatory System
		30.1 Circulatory Systems Deliver Nutrients and Remove Wastes
			A. Circulatory Systems Are Open or Closed
			B. Vertebrate Circulatory Systems Have Become Increasingly Complex
		30.2 Blood Is a Complex Mixture
			A. Plasma Carries Many Dissolved Substances
			B. Red Blood Cells Transport Oxygen
			C. White Blood Cells Fight Infection
			D. Blood Clotting Requires Platelets and Plasma Proteins
		30.3 Blood Circulates Through the Heart and Blood Vessels
		30.4 The Human Heart Is a Muscular Pump
			A. The Heart Has Four Chambers
			B. The Right and Left Halves of the Heart Deliver Blood Along Different Paths
			C. Cardiac Muscle Cells Produce the Heartbeat
			D. Exercise Strengthens the Heart
		30.5 Blood Vessels Form the Circulation Pathway
			A. Arteries, Capillaries, and Veins Have Different Structures
			B. Blood Pressure and Velocity Differ Among Vessel Types
		30.6 The Lymphatic System Maintains Circulation and Protects Against Infection
		30.7 Investigating Life: In (Extremely) Cold Blood
	31 The Respiratory System
		31.1 Gases Diffuse Across Respiratory Surfaces
			A. Some Invertebrates Exchange Gases Across the Body Wall or in Internal Tubules
			B. Gills Exchange Gases with Water
			C. Terrestrial Vertebrates Exchange Gases in Lungs
		31.2 The Human Respiratory System Delivers Air to the Lungs
			A. The Nose, Pharynx, and Larynx Form the Upper Respiratory Tract
			B. The Lower Respiratory Tract Consists of the Trachea and Lungs
		31.3 Breathing Requires Pressure Changes in the Lungs
		31.4 Blood Delivers Oxygen and Removes Carbon Dioxide
			A. Blood Carries Gases in Several Forms
			B. Blood Gas Levels Help Regulate the Breathing Rate
		31.5 Investigating Life: Why Do Bugs Hold Their Breath?
	32 Digestion and Nutrition
		32.1 Digestive Systems Derive Nutrients from Food
			A. Animals Eat to Obtain Energy and Building Blocks
			B. How Much Food Does an Animal Need?
			C. Animals Process Food in Four Stages
			D. Animal Diets and Feeding Strategies Vary Greatly
		32.2 Animal Digestive Tracts Take Many Forms
		32.3 The Human Digestive System Consists of Several Organs
			A. Digestion Begins in the Mouth
			B. The Stomach Stores, Digests, and Churns Food
			C. The Small Intestine Digests and Absorbs Nutrients
			D. The Large Intestine Completes Nutrient and Water Absorption
		32.4 A Healthy Diet Includes Essential Nutrients and the Right Number of Calories
			A. A Varied Diet Is Essential to Good Health
			B. Body Weight Reflects Food Intake and Activity Level
			C. Starvation: Too Few Calories to Meet the Body's Needs
			D. Obesity: More Calories Than the Body Needs
		32.5 Investigating Life: The Cost of a Sweet Tooth
	33 Regulation of Temperature and Body Fluids
		33.1 Animals Regulate Their Internal Temperature
			A. Heat Gains and Losses Determine an Animal's Body Temperature
			B. Several Adaptations Help an Animal to Adjust Its Temperature
		33.2 Animals Regulate Water and Ions in Body Fluids
		33.3 Nitrogenous Wastes Include Ammonia, Urea, and Uric Acid
		33.4 The Urinary System Produces, Stores, and Eliminates Urine
		33.5 The Nephron Is the Functional Unit of the Kidney
			A. Nephrons Interact Closely with Blood Vessels
			B. Urine Formation Includes Filtration, Reabsorption, and Secretion
			C. The Glomerular Capsule Filters Blood
			D. Reabsorption and Secretion Occur in the Renal Tubule
			E. The Collecting Duct Conserves More Water
			F. Hormones Regulate Kidney Function
		33.6 Investigating Life: Sniffing Out the Origin of Fur and Feathers
	34 The Immune System
		34.1 Many Cells, Tissues, and Organs Defend the Body
			A. White Blood Cells Play Major Roles in the Immune System
			B. The Lymphatic System Produces and Transports Many Immune System Cells
			C. The Immune System Has Two Main Subdivisions
		34.2 Innate Defenses Are Nonspecific and Act Early
			A. External Barriers Form the First Line of Defense
			B. Internal Innate Defenses Destroy Invaders
		34.3 Adaptive Immunity Defends Against Specific Pathogens
			A. Macrophages Trigger Both Cell-Mediated and Humoral Immunity
			B. Cytotoxic T Cells Provide Cell-Mediated Immunity
			C. B Cells Direct the Humoral Immune Response
			D. The Immune Response Turns Off Once the Threat Is Gone
			E. The Secondary Immune Response Is Stronger Than the Primary Response
		34.4 Vaccines Jump-Start Immunity
		34.5 Several Disorders Affect the Immune System
			A. Autoimmune Disorders Are Devastating and Mysterious
			B. Immunodeficiencies Lead to Opportunistic Infections
			C. Allergies Misdirect the Immune Response
			D. A Pregnant Woman's Immune System May Attack Her Fetus
		34.6 Investigating Life: The Hidden Cost of Hygiene
	35 Animal Reproduction and Development
		35.1 Animal Development Begins with Reproduction
			A. Reproduction Is Asexual or Sexual
			B. Gene Expression Dictates Animal Development
			C. Development Is Indirect or Direct
		35.2 Males Produce Sperm Cells
			A. Male Reproductive Organs Are Inside and Outside the Body
			B. Spermatogenesis Yields Sperm Cells
			C. Hormones Influence Male Reproductive Function
		35.3 Females Produce Egg Cells
			A. Female Reproductive Organs Are Inside the Body
			B. Oogenesis Yields Egg Cells
			C. Hormones Influence Female Reproductive Function
			D. Hormonal Fluctuations Can Cause Discomfort
		35.4 Reproductive Health Considers Contraception and Disease
		35.5 The Human Infant Begins Life as a Zygote
			A. Fertilization Initiates Pregnancy
			B. The Preembryonic Stage Ends When Implantation Is Complete
			C. Organs Take Shape During the Embryonic Stage
			D. Organ Systems Become Functional in the Fetal Stage
			E. Muscle Contractions in the Uterus Drive Childbirth
		35.6 Birth Defects Have Many Causes
		35.7 Investigating Life: The Ultimate Sacrifice
UNIT 7 The Ecology of Life
	36 Animal Behavior
		36.1 Animal Behaviors Have Proximate and Ultimate Causes
		36.2 Animal Behaviors Combine Innate and Learned Components
			A. Innate Behaviors Do Not Require Experience
			B. Learning Requires Experience
			C. Genes and Environment Interact to Determine Behavior
		36.3 Many Behaviors Improve Survival
			A. Some Animals Can Find Specific Locations
			B. Animals Balance the Energy Content and Costs of Acquiring Food
			C. Avoiding Predation Is Another Key to Survival
		36.4 Many Behaviors Promote Reproductive Success
			A. Courtship Sets the Stage for Mating
			B. Sexual Selection Leads to Differences Between the Sexes
			C. Animals Differ in Mating Systems and Degrees of Parental Care
			D. Human Reproductive Choices May Reflect Natural Selection
		36.5 Social Behaviors Often Occur in Groups
			A. Group Living Has Costs and Benefits
			B. Dominance Hierarchies and Territoriality Reduce Competition
			C. Kin Selection and Reciprocal Altruism Explain Some Acts of Cooperation
			D. Eusocial Animals Have Highly Developed Societies
		36.6 Investigating Life: The "Cross-Dressers" of the Reef
	37 Populations
		37.1 A Population Consists of Individuals of One Species
			A. Density and Distribution Patterns Are Static Measures of a Population
			B. Isolated Subpopulations May Evolve into New Species
		37.2 Births and Deaths Help Determine Population Size
			A. Births Add Individuals to a Population
			B. Survivorship Curves Show the Probability of Dying at a Given Age
		37.3 Population Growth May Be Exponential or Logistic
			A. Growth Is Exponential When Resources Are Unlimited
			B. Population Growth Eventually Slows
			C. Many Conditions Limit Population Size
		37.4 Natural Selection Influences Life Histories
			A. Organisms Balance Reproduction Against Other Requirements
			B. Opportunistic and Equilibrium Life Histories Reflect the Trade-Off Between Quantity and Quality
		37.5 The Human Population Continues to Grow
			A. Birth Rates and Death Rates Vary Worldwide
			B. The Ecological Footprint Is an Estimate of Resource Use
		37.6 Investigating Life: A Toxic Compromise
	38 Communities and Ecosystems
		38.1 Multiple Species Interact in Communities
			A. Many Species Compete for the Same Resources
			B. Symbiotic Interactions Can Benefit or Harm a Species
			C. Herbivory and Predation Link Species in Feeding Relationships
			D. Closely Interacting Species May Coevolve
		38.2 Succession Is a Gradual Change in a Community
		38.3 Ecosystems Require Continuous Energy Input
			A. Food Webs Depict the Transfer of Energy and Atoms
			B. A Keystone Species Has a Pivotal Role in the Community
			C. Heat Energy Leaves Each Food Web
			D. Harmful Chemicals May Accumulate in the Highest Trophic Levels
		38.4 Chemicals Cycle Within Ecosystems
			A. Water Circulates Between the Land and the Atmosphere
			B. Autotrophs Obtain Carbon as CO[sub(2)]
			C. The Nitrogen Cycle Relies on Bacteria
			D. The Phosphorus Cycle Begins with the Erosion of Rocks
			E. Excess Nitrogen and Phosphorus Cause Problems in Water
			F. Terrestrial and Aquatic Ecosystems Are Linked in Surprising Ways
		38.5 Investigating Life: Two Kingdoms and a Virus Team Up to Beat the Heat
	39 Biomes
		39.1 The Physical Environment Determines Where Life Exists
		39.2 Earth Has Diverse Climates
		39.3 Terrestrial Biomes Range from the Lush Tropics to the Frozen Poles
			A. Towering Trees Dominate the Forests
			B. Grasslands Occur in Tropical and Temperate Regions
			C. Whether Hot or Cold, All Deserts Are Dry
			D. Fire- and Drought-Adapted Plants Dominate Mediterranean Shrublands (Chaparral)
			E. Tundras Occupy High Latitudes and High Elevations
			F. Polar Ice Caps Are Cold and Dry
		39.4 Freshwater Biomes Include Lakes, Ponds, and Streams
			A. Lakes and Ponds Contain Standing Water
			B. Streams Carry Running Water
		39.5 Oceans Make Up Earth's Largest Ecosystem
			A. Land Meets Sea at the Coast
			B. The Open Ocean Remains Mysterious
		39.6 Investigating Life: There's No Place Like Home
	40 Preserving Biodiversity
		40.1 Earth's Biodiversity Is Dwindling
		40.2 Many Human Activities Destroy Habitats
		40.3 Pollution Degrades Habitats
			A. Water Pollution Threatens Aquatic Life
			B. Air Pollution Causes Many Types of Damage
		40.4 Global Climate Change Alters and Shifts Habitats
			A. Greenhouse Gases Warm Earth's Surface
			B. Global Climate Change Has Severe Consequences
		40.5 Exotic Invaders and Overexploitation Devastate Many Species
			A. Invasive Species Displace Native Organisms
			B. Overexploitation Can Drive Species to Extinction
		40.6 Some Biodiversity May Be Recoverable
			A. Protecting and Restoring Habitat Saves Many Species at Once
			B. Some Conservation Tools Target Individual Species
			C. Conserving Biodiversity Involves Scientists and Ordinary Citizens
		40.7 Investigating Life: Up, Up, and Away
APPENDIX A: Answers to Multiple Choice Questions
APPENDIX B: A Brief Guide to Statistical Significance
APPENDIX C: Units of Measurement
APPENDIX D: Periodic Table of the Elements
APPENDIX E: Amino Acid Structures
APPENDIX F: Learn How to Learn
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