1;Oxygen and the Evolution of Life;3 1.1;Preface;5 1.2;Contents;7 1.3;Abbreviations;11 1.4;Chapter 1: Oxygen, Its Nature and Chemistry: What Is so Special About This Element?;13 1.4.1;1.1 A Brief Introduction to Oxygen;13 1.4.2;1.2 Atomic Structure of Oxygen: Chemical Bonding Potential;14 1.4.3;1.3 The Dioxygen Molecule;17 1.4.4;1.4 Reactive Oxygen Species;20 1.4.4.1;1.4.1 Superoxide 1O2-*;20 1.4.4.2;1.4.2 Hydrogen peroxide (H2O2);21 1.4.4.3;1.4.3 Peroxyl radical (ROO*);21 1.4.5;1.5 Ozone;22 1.4.6;1.6 Water;24 1.4.7;1.7 Water Vapor in the Atmosphere;27 1.4.8;1.8 Carbon Dioxide;27 1.4.9;1.9 Solubility of Gases in Water;28 1.4.10;1.10 Hydrolysis and Dehydration: Central Water Reactions in Biology;28 1.4.11;1.11 Redox Reactions;29 1.4.12;References;30 1.5;Chapter 2: A Brief History of Oxygen;32 1.5.1;2.1 Cosmic History of the Elements;32 1.5.1.1;2.1.1 The Sun and Solar System;35 1.5.2;2.2 Formation of Earth;36 1.5.3;2.3 The Primordial Environment;38 1.5.3.1;2.3.1 Atmosphere of the Early Earth;38 1.5.3.2;2.3.2 Water on the Earth´ Surface: The Origin of Oceans;40 1.5.3.3;2.3.3 The First Greenhouse Effect;40 1.5.4;2.4 Life: Its Origins and Earliest Development;41 1.5.5;2.5 A Billion Years of Life Without Dioxygen: Anaerobic Metabolism;43 1.5.5.1;2.5.1 Some Principles of Metabolism;43 1.5.6;2.6 The Invention of Photosynthesis;46 1.5.7;2.7 How Oxygenic Photosynthesis Remodeled the Earth;49 1.5.7.1;2.7.1 The First Rise of Dioxygen;49 1.5.7.2;2.7.2 Effects on Life: An Ecological Catastrophe?;50 1.5.7.3;2.7.3 Effects on the Earth;51 1.5.8;References;52 1.6;Chapter 3: Coping with Oxygen;54 1.6.1;3.1 The Impact of Oxygenation on an Anaerobic World;54 1.6.2;3.2 Production of Reactive Oxygen Species;55 1.6.3;3.3 Coping with Reactive Oxygen Species;58 1.6.3.1;3.3.1 Scavenger Molecules;58 1.6.3.2;3.3.2 Enzymes for Detoxification of ROS;60 1.6.3.3;3.3.3 Antioxidant Enzyme Systems;62 1.6.4;3.4 How to Avoid Reactive Oxygen Species?;63 1.6.5;3.5 Evolving Defense Strategies;64 1.6.5.1;3.5.1 Aggregation for Defense;64 1.6.5.2;3.5.2 Melanin;65 1.6.5.3;3.5.3 Oxygen Transport Proteins Prevent Creation of Oxygen Radicals;66 1.6.6;3.6 Reactive Oxygen Species as Cellular Signals;67 1.6.7;3.7 Dioxygen as a Signal: Oxygen Sensor;67 1.6.8;3.8 Summary: Reactive Oxygen Species and Life;68 1.6.9;References;69 1.7;Chapter 4: Aerobic Metabolism: Benefits from an Oxygenated World;71 1.7.1;4.1 The Advantage to Being Aerobic;71 1.7.2;4.2 Evolution of an Aerobic Metabolism;72 1.7.2.1;4.2.1 Special Mechanisms Needed for Aerobic Metabolism;72 1.7.2.2;4.2.2 When and How Did Aerobes Arise?;73 1.7.3;4.3 Eukaryotes: The Next Step in Evolution;77 1.7.3.1;4.3.1 Distinction Between Prokaryotes and Eukaryotes;77 1.7.3.2;4.3.2 The Symbiotic Hypothesis;77 1.7.4;4.4 The Last Great Leap: Multicellular Organisms, ``Metazoans´´;79 1.7.4.1;4.4.1 When, Why, and How?;79 1.7.4.2;4.4.2 Collagen and Cholesterin;80 1.7.4.3;4.4.3 Half a Billion Years of Stasis?;81 1.7.4.4;4.4.4 Emergence and Extinction of the Ediacaran Fauna;82 1.7.4.5;4.4.5 The Bilateral Body Plan;83 1.7.4.6;4.4.6 The ``Cambrian Explosion´´: Fact or Artifact?;84 1.7.5;References;86 1.8;Chapter 5: Facilitated Oxygen Transport;88 1.8.1;5.1 How to Deliver Dioxygen to Animal Tissues?;88 1.8.2;5.2 Modes of Delivery;89 1.8.2.1;5.2.1 Diffusion from the Surface;89 1.8.2.2;5.2.2 Transport via Blood as a Dissolved Gas;90 1.8.2.3;5.2.3 Oxygen Transport Proteins: What They Must Do?;91 1.8.3;5.3 Modes of Dioxygen Binding to Oxygen Transport Proteins;93 1.8.3.1;5.3.1 Cooperative and Noncooperative Binding;93 1.8.3.2;5.3.2 How Does Cooperativity Work?: Models for Allostery;95 1.8.3.3;5.3.3 Self-Assembly and Nesting;97 1.8.3.4;5.3.4 Why Complex Multisubunit Oxygen Transport Proteins?;98 1.8.4;5.4 Modulation of Dioxygen Delivery by Oxygen Transport Proteins: Heteroallostery;98 1.8.4.1;5.4.1 Modulation by the Products of Anaerobic Metabolism: the Bohr Effect;99 1.8.4.2;5.4.2 The Haldane Effect;99 1.8.4.3;5.4.3 The Root Effect;100 1.8.4.4;5.