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Evolution



1.1 Unity and Diversity of Life on Earth

1.1.1 Properties of Life




1.2 Early Perspectives in Science

1.2.1 An Introduction to Biology

1.2.2 The Nature of Science: The Story of Darwin

1.2.3 Early Scientific Thought

1.2.4 The Emerging Science of Geology




1.3 An Introduction to Evolution

1.3.1 Linnaeus, Buffon, and Lamarck

1.3.2 Darwin: The Voyage Continues

1.3.3 Darwin: More Observations




1.4 Evolution: The Theory of Natural Selection

1.4.1 Darwin: The Theory of Natural Selection

1.4.2 The Theory of Natural Selection

1.4.3 Contrasting Lamarck and Darwin

1.4.4 Contrasting Lamarck and Darwin, Part II




1.5 Fossils and Evolution

1.5.1 Fossil Formation, Dating, and Indexing

1.5.2 The Fossil Record

1.5.3 Some Fossil Surprises

1.5.4 The Coevolution of Horses and Plants

1.5.5 Mass Extinctions: An Asteroid Can Ruin Your Day




1.6 Human Evolution

1.6.1 Human Evolution: What Is a Primate?

1.6.2 Human Evolution: The Family Tree

1.6.3 Human Evolution: The Fossil Record




1.7 Evidence for Evolution

1.7.1 Evidence for Evolution: Biochemical Similarities

1.7.2 Evidence for Evolution: Vestigial Structures

1.7.3 Homologous Structures




1.8 Species Concepts

1.8.1 Species Concepts

1.8.2 Speciation

1.8.3 Prezygotic Reproductive Isolation

1.8.4 Postzygotic Reproductive Isolation




1.9 Examples of Artificial and Natural Selection

1.9.1 Artificial Selection in Action

1.9.2 Natural Selection in Action




1.10 The Origin of Life

1.10.1 History of Life: The Heterotroph Hypothesis: An Overview

1.10.2 The Heterotroph Hypothesis: An Introduction

1.10.3 The Origin of Life: Life from Nonlife

1.10.4 The Heterotroph Hypothesis: Protobionts

1.10.5 The Heterotroph Hypothesis: The First Genetic Material

1.10.6 The Origin of Life: The Rest of the Story




1.11 Classifying Life

1.11.1 The Linnaean System

1.11.2 The Linnaean System: Still Changing

Inorganic and Organic Chemistry



2.1 An Introduction to Atoms

2.1.1 Atomic Structure: SPONCH and the Atom

2.1.2 Electrons, Orbitals, and Electron Shells

2.1.3 Ions, Ionization, and Isotopes

2.1.4 Isotopes: Unraveling Photosynthesis




2.2 Atoms and Bonding

2.2.1 Bonding and Electronegativity

2.2.2 Ionic and Covalent Bonds

2.2.3 Polar Covalent Bonds, Hydrogen Bonds, and Van der Waals Interactions




2.3 Properties of Water

2.3.1 Water: Hydrogen Bonding, Solubility, and Specific Heat

2.3.2 Water: Adhesion, Cohesion, and a Solid That Floats

2.3.3 Water: Hydrophilic and Hydrophobic Substances

2.3.4 Dissociation of Water and the pH Scale

2.3.5 Hemoglobin as a Buffer




2.4 Carbon Chemistry

2.4.1 Carbon Chemistry and Isomers

2.4.2 Functional Side Groups




2.5 Carbohydrates

2.5.1 Carbohydrates: Monosaccharides

2.5.2 Dehydration Synthesis and Hydrolysis: Disaccharides

2.5.3 Polysaccharides: Energy Storage Molecules

2.5.4 Polysaccharides: Structural Molecules




2.6 Lipids and Nucleic Acids

2.6.1 Lipids: An Introduction

2.6.2 Saturated vs. Unsaturated Fats

2.6.3 Phospholipids, Waxes, and Steroids

2.6.4 Nucleic Acids: An Introduction to Genetic Material




2.7 Proteins

2.7.1 Proteins: Amino Acids and the Peptide Bond

2.7.2 Amino Acids: The R Groups

2.7.3 Primary and Secondary Structure

2.7.4 Tertiary Structure

2.7.5 Quaternary Structure

2.7.6 Protein Structure: A Summary




2.8 Enzymes

2.8.1 Bioenergetics: The Laws of Thermodynamics

2.8.2 Activation Energy

2.8.3 Enzyme Characteristics




2.9 Enzyme Action

2.9.1 Enzyme Action: The Induced-Fit Model

2.9.2 Enzyme Regulation: Allosteric Regulation

2.9.3 Feedback Inhibition and Cooperativity

Cell Biology



3.1 An Introduction to Cell Biology

3.1.1 The History of Cytology

3.1.2 Prokaryotes vs. Eukaryotes

3.1.3 Plant and Animal Cell Overview: The Basics

3.1.4 Membranes: Basic Structure

3.1.5 The Nuclear Envelope: The Initial Tour

3.1.6 Nuclear Function: Who's in Charge?




3.2 Membrane-Bound Organelles

3.2.1 Cellular Function: Endoplasmic Reticulum

3.2.2 Cell Function: Golgi Apparatus

3.2.3 Food Vacuole Formation: The Role of the Lysosome

3.2.4 Still More Vacuoles and Peroxisomes

3.2.5 Mitochondria: Welcome Guests

3.2.6 The Origin of Mitochondria and Chloroplasts




3.3 The Cytoskeleton

3.3.1 The Cytoskeleton: Basic Components

3.3.2 Centrioles, Flagella, and Cilia

3.3.3 Cell Walls




3.4 The Plasma Membrane

3.4.1 Plasma Membrane: The Extracellular Matrix

3.4.2 The Plasma Membrane: The Fluid-Mosaic Model

3.4.3 Proteins as the Mosaic of the Cell Membrane

3.4.4 Animal Cell Junctions




3.5 Cell Transport

3.5.1 Simple and Facilitated Diffusion

3.5.2 Passive Transport: Osmosis

3.5.3 Active Transport: Ion Pumps and Cotransport

3.5.4 Active Transport: The Sodium-Potassium Pump

3.5.5 Energy-Requiring Transport: Endocytosis and Exocytosis




3.6 Tools for Cell Biology

3.6.1 Tools of the Cytologist: Light and Fluorescent Microscopy

3.6.2 Scanning and Transmission Electron Microscopes

3.6.3 Freeze Fracture and Differential Centrifugation




3.7 The Evolution of Metabolic Functions

3.7.1 Major Modes of Nutrition Among Organisms

Respiration



4.1 An Introduction to Respiration

4.1.1 ATP Structure and Function

4.1.2 Phosphorylated Intermediates

4.1.3 Respiration: An Overview

4.1.4 Redox: A Brief Review

4.1.5 Energy Release from Sugar: A Demo

4.1.6 Coenzymes: The Role of NAD⁺




4.2 Glycolysis and Fermentation

4.2.1 Glycolysis: The Initial Steps: Energy Input

4.2.2 Glycolysis: The Energy Payoff

4.2.3 Anaerobic Respiration: The Fermentation of Pyruvate




4.3 Aerobic Respiration

4.3.1 Aerobic Respiration: The Acetyl CoA Step

4.3.2 Aerobic Respiration: The Krebs Cycle

4.3.3 Glycolysis and the Krebs Cycle




4.4 The Electron Transport Chain and Oxidative Phosphorylation

4.4.1 The Electron Transport Chain

4.4.2 Oxidative Phosphorylation

4.4.3 ATP Yield from Aerobic Respiration

4.4.4 Other Fuels in Respiration

4.4.5 The Evolution of Glycolysis

Photosynthesis



5.1 Discovering Photosynthesis

5.1.1 The Unraveling of Photosynthesis: A Historical Perspective

5.1.2 Photosynthesis: Twentieth-Century Breakthroughs

5.1.3 Photosynthesis: The Final Picture




5.2 Adaptations for Photosynthesis

5.2.1 The Leaf: Adaptations for Photosynthesis

5.2.2 The Structure of a Chloroplast

5.2.3 Photosynthetic Pigments

5.2.4 The Nature of Light

5.2.5 Photoexcitation and Electron Transfer




5.3 The Light Reactions

5.3.1 The Light Reactions: An Introduction

5.3.2 Photosystem 1

5.3.3 Photosystem 2

5.3.4 The Light Reactions: A Summary




5.4 The Dark Reactions

5.4.1 The Calvin Cycle

5.4.2 The Calvin Cycle: RuBP Regeneration

5.4.3 A Review of Photosynthesis




5.5 Photorespiration

5.5.1 Photorespiration

5.5.2 C₄ Plants and CAM Plants

5.5.3 The Evolution of Photosynthesis

Molecular Genetics



6.1 Discovering DNA

6.1.1 Molecular Genetics: The Protein vs. DNA Debate

6.1.2 Continuing to Link Genes to Chemicals: Muller, Beadle, and Tatum

6.1.3 Griffith and Transformation

6.1.4 Avery, MacLeod and McCarty/Hershey and Chase: DNA Wins!

6.1.5 Chargaff and Franklin and Wilkins: The DNA Story Begins




6.2 DNA Structure Revealed

6.2.1 Watson and Crick: The Clues

6.2.2 Watson and Crick: The Double Helix




6.3 Introduction to DNA Replication

6.3.1 Replication: Meselson and Stahl

6.3.2 DNA: Polymerization with Triphosphate Nucleotides




6.4 Events of DNA Replication

6.4.1 Events at the Replication Fork: The Leading Strand

6.4.2 Events at the Leading Strand, Part II

6.4.3 Events at the Replication Fork: The Lagging Strand

6.4.4 Proofreading, End Replication, and Telomeres

6.4.5 DNA Replication: A Summary




6.5 Transcription

6.5.1 Transcription and Translation: An Overview

6.5.2 Transcription: RNA Formation from the DNA Template

6.5.3 Transcription: Termination and RNA Protection

6.5.4 Posttranscriptional Modification/RNA Splicing




6.6 Translation

6.6.1 Translation: Ribosomal and Transfer RNA

6.6.2 The Role of Transfer RNA: Charging a tRNA Molecule

6.6.3 Translation: Initiation Events

6.6.4 Translation/Elongation: The Initiation of Elongation

6.6.5 Elongation Continued and Termination




6.7 Protein Synthesis Review

6.7.1 Polypeptide Destinations: Signal Peptides and ER Ribosomes

6.7.2 Protein Synthesis: An Overview




6.8 The lac Operon

6.8.1 Control Mechanisms: Lactose Metabolism in E. coli

6.8.2 Jacob and Monod's Model: The lac Operon

6.8.3 lac Operon: The Summary




6.9 Eukaryotic Genomic Organization

6.9.1 The Eukaryotic Genome: DNA Packing

6.9.2 Eukaryotic Genomic Organization: Repetitive DNA

6.9.3 Eukaryotic Genomic Organization: Gene Families

6.9.4 Eukaryotic Genomic Organization: Transposons and Amplified Genes




6.10 Controlling Protein Synthesis in Eukaryotes

6.10.1 Eukaryotic Gene Control: Transcriptional Controls

6.10.2 Eukaryotic Control Mechanisms: Posttranscriptional and Posttranslational Controls

6.10.3 Prokaryotes vs. Eukaryotes: Protein-Making Machinery

Biotechnology



7.1 Plasmids and Gene Cloning

7.1.1 Biotechnology: Plasmids in Prokaryotes

7.1.2 Using a Restriction Enzyme to Create a Vector

7.1.3 Biotechnology: Gene Cloning

7.1.4 Biotechnology: Detection of Cell Clones




7.2 Techniques in Biotechnology

7.2.1 Biotechnology: Reverse Transcriptase: A Tool Taken from Viruses

7.2.2 Using Reverse Transcriptase to Make cDNA

7.2.3 Electrophoresis: Separating DNA

7.2.4 Sequencing DNA: The Sanger Method




7.3 More Techniques in Biotechnology

7.3.1 Restriction Fragment Length Polymorphisms: Genetic Markers

7.3.2 Polymerase Chain Reaction: DNA Amplification

7.3.3 DNA Fingerprinting

7.3.4 Southern Blotting

7.3.5 Detecting DNA Homology: A Biotechnology Summary




7.4 Human Genome Project

7.4.1 The Human Gene Pool

7.4.2 The Human Genome Project: Recent Findings

Cell Reproduction



8.1 An Introduction to the Cell Cycle and Mitosis

8.1.1 The Eukaryotic Cell Cycle

8.1.2 Mitosis: An Overview

8.1.3 Mitosis: The Phases

8.1.4 Cytokinesis




8.2 Regulating Mitosis

8.2.1 Cell-Cycle Regulation: Protein Kinases

8.2.2 Cell-Cycle Regulation: Other Mechanisms

8.2.3 Cancer: When Mitosis Goes Unchecked

8.2.4 The ras Gene and the p53 Gene




8.3 Meiosis

8.3.1 Sexual Reproduction and the Role of Meiosis

8.3.2 Homologous Chromosomes: Thanks, Mom and Dad!

8.3.3 Meiosis: Prophase I

8.3.4 Disjunction and Meiosis II

8.3.5 Mitosis vs. Meiosis




8.4 Understanding Meiosis

8.4.1 Independent Assortment

8.4.2 Spermatogenesis: Meiosis in Males

8.4.3 Oogenesis: Meiosis in Females

Mendelian Genetics and Mutation



9.1 Gregor Mendel

9.1.1 Heredity: The Story of Gregor Mendel

9.1.2 Mendel's Findings: A First Look at Phenotypic Ratios

9.1.3 Mendel's Conclusions: Alternate Alleles and Dominance

9.1.4 Mendel's Conclusions: Segregation and Recombination




9.2 The Laws of Mendelian Inheritance

9.2.1 Determining Heterozygosity: Test Crosses and Back Crosses

9.2.2 Mendelian Inheritance




9.3 Segregation and Independent Assortment

9.3.1 Segregation and Independent Assortment

9.3.2 Independent Assortment: An Explanation




9.4 Laws of Probability

9.4.1 Laws of Probability: Rule of Multiplication

9.4.2 The Multiplicative Law: Some Extensions

9.4.3 Laws of Probability: The Additive Rule

9.4.4 Using the Laws of Probability in Dihybrid Crosses




9.5 Genetic Dominance

9.5.1 What Is a Dominant Gene? Intermediate Inheritance

9.5.2 Codominance and Multiple Alleles: ABO Blood Genes

9.5.3 ABO Blood Groups: Inheritance Patterns and Pedigree Charts




9.6 Epistasis

9.6.1 Epistasis: One Gene Affecting Another

9.6.2 The Bombay Phenotype: Infidelity or Epistasis?




9.7 Inheritance Patterns

9.7.1 Polygenic Inheritance

9.7.2 Pleiotropy: Multiple Phenotypic Effects

9.7.3 Sickle Cell Anemia: The Case against Dominant and Recessive




9.8 Linked Genes and Genetic Mapping

9.8.1 Linked Genes

9.8.2 Crossing Over and Recombination: A Tool for Mapping Genes

9.8.3 Gene Mapping Using Recombination Frequencies

9.8.4 Linking Genes to Chromosomes: The Work of Morgan

9.8.5 Morgan's Conclusions




9.9 Sex Linkage and Pedigree Charts

9.9.1 Sex-Linked Traits in Humans

9.9.2 X Inactivation in Humans

9.9.3 The Use of Pedigree Charts to Determine Possible Genotypes

9.9.4 Pedigree Chart: Problem Review




9.10 Problems in Heredity

9.10.1 Problems in Heredity

9.10.2 Problems in Heredity: Chromosomal Aberrations

9.10.3 Translocations: 14/21 Downs




9.11 Genetic Mutation

9.11.1 Genetic Mutation

9.11.2 Genetic Mutation: Different Forms of Point Mutations

9.11.3 Genetic Mutation: Insertion and Deletion

9.11.4 Genetic Screening

Population Genetics and Evolution



10.1 The Hardy-Weinberg Theory

10.1.1 Population Genetics: Darwin Meets Mendel

10.1.2 An Introduction to Hardy-Weinberg Theory

10.1.3 The Hardy-Weinberg Equation

10.1.4 Using the Hardy-Weinberg Theory

10.1.5 Using the Hardy-Weinberg Theory II

10.1.6 Hardy-Weinberg: What Does This Have to Do with Evolution?




10.2 Departing From Hardy-Weinberg Equilibrium

10.2.1 Microevolution by Genetic Drift

10.2.2 Microevolution: Continued




10.3 Variations in Populations and Modes of Selection

10.3.1 Variations within and between Populations

10.3.2 Modes of Selection

10.3.3 The Perfect Organism




10.4 Speciation

10.4.1 Speciation: What Is a Species?

10.4.2 Allopatric Speciation

10.4.3 Sympatric Speciation




10.5 Evolution

10.5.1 Time Frame for Evolution: Gradualism versus Punctuated Equilibrium

The Evolution of Life on Earth



11.1 Classifying Earth's Organisms

11.1.1 Classifying the Products of Evolution: Taxonomy

11.1.2 Building a Cladogram

11.1.3 Molecular Methods for Classifying Organisms

11.1.4 A Phylogenetic Tree of Organisms: A Three-Domain System




11.2 Domain Archaea

11.2.1 The Archaea




11.3 Domain Bacteria

11.3.1 The Bacteria




11.4 Protists and the Origin of the Eukaryota

11.4.1 Protists: Archaezoa and Euglenozoa

11.4.2 Protists: Alveolata and Stramenopila




11.5 The Colonization of Land by Plants

11.5.1 Plant Phylogeny: The Colonization of Land

11.5.2 Plant Phylogeny and Alternation of Generations




11.6 Alternation of Generations: Mosses, Ferns, and Gymnosperms

11.6.1 Alternation of Generations: Mosses

11.6.2 Alternation of Generations: Ferns

11.6.3 Alternation of Generations: Gymnosperms




11.7 Angiosperms

11.7.1 Alternation of Generations: The Structure of a Flower

11.7.2 Alternation of Generations: Angiosperms

11.7.3 Embryogenesis in Angiosperms: Dicots and Monocots




11.8 Fungi

11.8.1 Introduction to the Fungi

11.8.2 Diversity of Fungi




11.9 Evolution of the Animal Kingdom

11.9.1 Constructing a Phylogenetic Tree of Animals: Animal Development

11.9.2 Developmental Data for the Phylogenetic Tree of Animals

11.9.3 The Formation of Body Cavities

11.9.4 Protostomes and Deuterostomes

11.9.5 Animal Diversity: The Cambrian Explosion and the Move to Land




11.10 Invertebrates

11.10.1 Introduction to Animals: Parazoa and Radiata

11.10.2 Animals: Acoelomates, Pseudocoelomates, and Coelomates

11.10.3 Diversity of Protostome Species




11.11 Deuterostomes

11.11.1 Diversity of Deuterostome Species

11.11.2 Diversity of Vertebrate Species




11.12 Chordate Development

11.12.1 Animal Development: A Close-up Look at Fertilization Events

11.12.2 Cleavage, Gastrulation, and Organogenesis: A Closer Look

11.12.3 Events of Gastrulation and Organogenesis




11.13 The Cellular and Molecular Basis of Development

11.13.1 Pattern Formation in Drosophila

11.13.2 Pattern Formation in Drosophila, continued




11.14 Viruses and Prions

11.14.1 Viruses and Prions: Living or Nonliving?

Animal Systems and Homeostasis



12.1 Introduction to Animal Systems and Homeostasis

12.1.1 Animal Homeostasis

12.1.2 Mechanisms of Homeostasis

12.1.3 Animal Tissues: Epithelial Tissue

12.1.4 Animal Tissues: Loose Connective Tissue

12.1.5 Animal Tissues: Dense, Fluid, and Supportive Connective Tissue

12.1.6 Animal Tissue: Muscle and Nerve Tissue




12.2 The Digestive System

12.2.1 Introduction to the Digestive System

12.2.2 The Beginning of Chemical Digestion

12.2.3 Chemical Digestion in the Small Intestine

12.2.4 Human Nutrition: Absorption

12.2.5 Egestion




12.3 Gas Exchange and Transport Systems

12.3.1 Introduction to the Gas Exchange of Animals

12.3.2 Human Gas Exchange System

12.3.3 Human Gas Exchange: The Roles of Respiratory Pigments

12.3.4 Carbon Dioxide Transport

12.3.5 Structure of the Human Heart




12.4 Circulation

12.4.1 Maintaining the Human Heartbeat

12.4.2 Human Circulation: Blood Vessels




12.5 Blood Pressure and Clotting

12.5.1 Human Circulation: Blood Pressure

12.5.2 Blood Clotting




12.6 Human Excretion

12.6.1 Human Excretion: Waste Processing

12.6.2 Human Excretion: Urinary System Structure

12.6.3 The Nephron: Blood Filtration and Urine Production




12.7 The Immune System: An Introduction

12.7.1 The Immune Response: Nonspecific Defenses

12.7.2 The Immune System: Structure and Function

12.7.3 Immunity: Clonal Selection Theory

12.7.4 Immune Response: An Overview

12.7.5 T Cells: Helper T Activation

12.7.6 T Cells: Helper and Cytotoxic T Cell Effects




12.8 The Immune System Continued

12.8.1 B Cells: The Humoral Response

12.8.2 Antibodies and DNA Rearrangement

12.8.3 Antibody Mechanisms




12.9 HIV and the Immune System

12.9.1 HIV: An Attack on the Immune System




12.10 The Endocrine System

12.10.1 Human Regulation: Endocrine Control and Signal-Transduction Pathways

12.10.2 The Endocrine System

12.10.3 Endocrine Function: Oscillations in Hormone Levels




12.11 The Ovarian and Uterine Cycles

12.11.1 The Ovarian and Uterine Cycles: Preparation for Pregnancy

12.11.2 Hormonal Events during the Female Reproductive Cycle




12.12 The Nervous System

12.12.1 The Central and Peripheral Nervous Systems and the Neuron

12.12.2 Human Regulation: Nervous System: Nerve Function and Reflexes




12.13 The Nerve Impulse

12.13.1 Human Regulation: The Nerve Impulse: General Events

12.13.2 Human Regulation: The Nervous System and the Action Potential

12.13.3 Human Regulation: Synaptic Events: Cell-Cell Communication

12.13.4 The Nervous System: A Phylogenetic Perspective

12.13.5 The Human Brain

12.13.6 Processing Centers of the Human Brain




12.14 Motor Mechanisms

12.14.1 Motor Control: Muscle Microstructure

12.14.2 The Neuromuscular Junction: The Contraction Is Triggered

12.14.3 The Sliding Filament: Interaction of ATP, Actin, Myosin, and Calcium




12.15 Sensory Reception

12.15.1 Sensory Systems: An Introduction

12.15.2 Photoreceptors and the Vertebrate Eye

12.15.3 The Ear and Equilibrium

12.15.4 The Ear and Hearing

Plant Systems and Homeostasis



13.1 Plant Development

13.1.1 Plant Development: Germination

13.1.2 Plant Development: Cell Structure and Function

13.1.3 Primary Growth: Root Growth and Development

13.1.4 Primary Growth: Stem Growth and Development

13.1.5 Secondary Growth: Lateral Meristems and Secondary Vascular Tissue




13.2 Plant Hormones

13.2.1 Regulation in Plants

13.2.2 Plant Hormones

13.2.3 Signal Transduction Pathways in Plants




13.3 Photoperiodism

13.3.1 Photoperiodism in Plants: Control of Flowering

13.3.2 Phytochromes and the Photoperiodic Response




13.4 Plant Transport

13.4.1 Transport in Angiosperms: Transpiration

13.4.2 The Role of Xylem Tissue and Stomata

13.4.3 Plant Transport: Absorption and Lateral Transport in Roots

13.4.4 Phloem: The Movement of Sap

Ecology



14.1 Introduction to Ecology

14.1.1 Ecological Organization: The Functional Divisions of the Ecologist




14.2 Biomes

14.2.1 Land Biomes: An Overview

14.2.2 Terrestrial Biomes: Water-Limited Environments

14.2.3 Aquatic Biomes




14.3 Animal Behavior

14.3.1 Ecology at the Level of the Species: Behavior

14.3.2 Imprinting and Innate Behavior

14.3.3 Nature versus Nurture: Is There a Genetic Basis for Behaviors?




14.4 Competitive and Courtship Behaviors

14.4.1 Competitive Behaviors and Survivability

14.4.2 Courtship and Mating Behaviors: Survivability




14.5 Population Ecology

14.5.1 Population Ecology: Populations with Unlimited Resources

14.5.2 Population Ecology: The Reality of Limited Resources

14.5.3 Population Ecology: Population Strategy: r vs K

14.5.4 Population Ecology: Intraspecific Competition




14.6 Community Ecology: Interspecific Interactions

14.6.1 Community Ecology: Interspecific Interaction: Predation

14.6.2 Interspecific Competition: Ecological Niches

14.6.3 Interspecific Associations: Symbiosis




14.7 Community Ecology: Succession

14.7.1 Community Disturbance: Succession

14.7.2 Secondary Succession




14.8 Community Ecology: Species Diversity

14.8.1 The Decline in Species Diversity and the Current Mass Extinction




14.9 Energy Flow in an Ecosystem

14.9.1 Ecosystems: A Flow of Energy

14.9.2 Ecosystems: Productivity and Energy Flow

14.9.3 Productivity Pyramids: Visualizing Energy Flows

14.9.4 Productivity Pyramids: Pyramid of Numbers




14.10 Chemical Cycling in the Ecosystem

14.10.1 Ecosystems and Material Cycles: Water, Carbon, and Sulfur

14.10.2 Ecosystems and Material Cycles: Nitrogen and Phosphorus Cycles




14.11 Human Effect on the Ecosystem

14.11.1 The Effects of Human Population Growth: Lake Eutrophication

14.11.2 Toxic Accumulation and Ozone Depletion

George Wolfe
Loudon County Schools Academy of Science

George Wolfe brings 30+ years of teaching and curriculum writing experience to Thinkwell Biology. His teaching career started in Zaire, Africa where he taught Biology, Chemistry, Political Economics, and Physical Education in the Peace Corps. Since then, he's taught in the Western NY region, spending the last 20 years in the Rochester City School District where he is the Director of the Loudoun Academy of Science.

Besides his teaching career, Mr. Wolfe has also been an Emmy-winning television host, fielding live questions for the PBS/WXXI production of Homework Hotline as well as writing and performing in "Football Physics" segments for the Buffalo Bills and the Discover Channel.

His contributions to education have been extensive, serving on multiple advisory boards including the Cornell Institute of Physics Teachers, the Cornell Institute of Biology Teachers and the Harvard-Smithsonian Center for Astrophysics SportSmarts curriculum project. He has authored several publications including "The Nasonia Project", a lab series built around the genetics and behaviors of a parasitic wasp.

He has received numerous awards throughout his teaching career including the NSTA Presidential Excellence Award, The National Association of Biology Teachers Outstanding Biology Teacher Award for New York State, The Shell Award for Outstanding Science Educator, and was recently inducted in the National Teaching Hall of Fame.