Theory of Adaptation.Origin of Life and of Metabolic Pathways.Adaptational Genetics.Biological Variation, Molecular Clocks and Speciation.Enzyme Kinetics and Protein Structure.Oxygen.Temperature.Hydrostatic Pressure.Water and Ions.Animal Behavior.Simple Nervous Systems, Fixed Action Patterns.Transmission Between Neurons.Electron Reception, Audio Reception and Behavior.Photoreception and Vision.Bioelectric Properties of Cell Membranes.Motility; Muscles.General Summary.Index.