Introduction Molecular Biology of Omega-3 Chains as Structural Lipids: Many Central Questions Remain Unanswered Evolution of DHA and the Membrane Darwinian Selection of the Fittest Membrane Lipids: From Archaeal Isoprenoids to DHA-Enriched Rhodopsin Disks Coevolution of DHA Membranes and Their Proteins Convergent Evolution of DHA/EPA Biosynthetic Pathways Membrane Evolution in a Marine Bacterium: Capitalizing on DHA for Energy Conservation in Seawater Evolution of DHA Membranes in Human Neurons General Properties of Omega-3s and Other Membrane Lipids DHA/EPA Chains as Powerful Membrane Antifreeze DHA as a Mediocre Permeability Barrier against Cations: Water Wire Theory DHA/EPA Membranes as Targets of Oxidative Damage Cellular Biology of Omega-3s and Other Membrane Lipids Bacteria: Environmental Modulation of Membrane Lipids for Bioenergetic Gain Chloroplasts: Harnessing DHA/EPA for Harvesting Light in the Sea Mitochondria: DHA-Cardiolipin Boosts Energy Output Sperm: Essential Roles of DHA Lead to Development of a Mechanical Stress Hypothesis Lessons and Applications DHA/EPA Mutualism between Bacteria and Marine Animals Membrane Adaptations for an Oily Environment: Lessons from a Petroleum-Degrading Bacterium Lessons from Yeast: Phospholipid Conformations Are Important in Winemaking DHA Principle Applied to Global Warming DHA Principle Applied to Molecular Farming DHA/Unsaturation Theory of Aging DHA Principle Applied to Neurodegenerative Diseases Dietary DHA in Prevention of Colon Cancer: How a Risk to the Cell Benefits the Organism Index s Powerful Membrane Antifreeze DHA as a Mediocre Permeability Barrier against Cations: Water Wire Theory DHA/EPA Membranes as Targets of Oxidative Damage Cellular Biology of Omega-3s and Other Membrane Lipids Bacteria: Environmental Modulation of Membrane Lipids for Bioenergetic Gain Chloroplasts: Harnessing DHA/EPA for Harvesting Light in the Sea Mitochondria: DHA-Cardiolipin Boosts Energy Output Sperm: Essential Roles of DHA Lead to Development of a Mechanical Stress Hypothesis Lessons and Applications DHA/EPA Mutualism between Bacteria and Marine Animals Membrane Adaptations for an Oily Environment: Lessons from a Petroleum-Degrading Bacterium Lessons from Yeast: Phospholipid Conformations Are Important in Winemaking DHA Principle Applied to Global Warming DHA Principle Applied to Molecular Farming DHA/Unsaturation Theory of Aging DHA Principle Applied to Neurodegenerative Diseases Dietary DHA in Prevention of Colon Cancer: How a Risk to the Cell Benefits the Organism Index ily Environment: Lessons from a Petroleum-Degrading Bacterium Lessons from Yeast: Phospholipid Conformations Are Important in Winemaking DHA Principle Applied to Global Warming DHA Principle Applied to Molecular Farming DHA/Unsaturation Theory of Aging DHA Principle Applied to Neurodegenerative Diseases Dietary DHA in Prevention of Colon Cancer: How a Risk to the Cell Benefits the Organism Index.