Astrobiology

  1. Life on Earth: Origins and Evolution
    1. Defining Life
      1. Universal Characteristics
        1. Cellular Organization
          1. Metabolism
            1. Homeostasis
              1. Growth and Reproduction
                1. Heredity
                  1. Evolution
                  2. Working Definitions
                    1. NASA Definition
                      1. Thermodynamic Definitions
                        1. Information-Based Definitions
                        2. Borderline Cases
                          1. Viruses
                            1. Prions
                              1. Self-Replicating Systems
                            2. Essential Requirements for Life
                              1. Liquid Water
                                1. Solvent Properties
                                  1. Temperature Stability Range
                                    1. Chemical Reactivity
                                    2. Carbon Chemistry
                                      1. Bonding Versatility
                                        1. Molecular Complexity
                                          1. Alternative Biochemistries
                                          2. Energy Sources
                                            1. Photosynthesis
                                              1. Chemosynthesis
                                                1. Fermentation
                                                  1. Respiration
                                                  2. Information Storage and Transfer
                                                    1. DNA Structure and Function
                                                      1. RNA Roles
                                                        1. Protein Synthesis
                                                      2. Origin of Life Theories
                                                        1. Primordial Soup Hypothesis
                                                          1. Miller-Urey Experiments
                                                            1. Atmospheric Composition Debates
                                                              1. Organic Synthesis Pathways
                                                              2. Hydrothermal Vent Origins
                                                                1. Black Smokers
                                                                  1. Alkaline Vents
                                                                    1. Iron-Sulfur World
                                                                      1. pH and Redox Gradients
                                                                      2. RNA World Hypothesis
                                                                        1. Ribozyme Discovery
                                                                          1. Self-Replication Mechanisms
                                                                            1. Transition to DNA-Protein World
                                                                            2. Metabolism-First Theories
                                                                              1. Autocatalytic Networks
                                                                                1. Reverse Citric Acid Cycle
                                                                                2. Lipid World Hypothesis
                                                                                  1. Membrane Formation
                                                                                    1. Protocell Development
                                                                                  2. Early Earth Conditions
                                                                                    1. Hadean Eon Environment
                                                                                      1. Atmospheric Composition
                                                                                        1. Surface Temperature
                                                                                          1. Impact Bombardment
                                                                                          2. Archean Eon Developments
                                                                                            1. First Oceans
                                                                                              1. Continental Formation
                                                                                                1. Atmospheric Evolution
                                                                                                2. Prebiotic Chemistry
                                                                                                  1. Organic Compound Formation
                                                                                                    1. Polymerization Processes
                                                                                                      1. Chirality Selection
                                                                                                    2. Evolution of Early Life
                                                                                                      1. Last Universal Common Ancestor
                                                                                                        1. Phylogenetic Evidence
                                                                                                          1. Metabolic Characteristics
                                                                                                            1. Genetic Code Origins
                                                                                                            2. Prokaryotic Diversification
                                                                                                              1. Bacteria
                                                                                                                1. Archaea
                                                                                                                  1. Metabolic Innovations
                                                                                                                  2. Photosynthesis Evolution
                                                                                                                    1. Anoxygenic Photosynthesis
                                                                                                                      1. Oxygenic Photosynthesis
                                                                                                                        1. Cyanobacteria
                                                                                                                        2. Great Oxidation Event
                                                                                                                          1. Atmospheric Oxygenation
                                                                                                                            1. Banded Iron Formations
                                                                                                                              1. Mass Extinction
                                                                                                                                1. Eukaryotic Prerequisites
                                                                                                                              2. Major Evolutionary Transitions
                                                                                                                                1. Eukaryotic Cell Origin
                                                                                                                                  1. Endosymbiotic Theory
                                                                                                                                    1. Mitochondrial Evolution
                                                                                                                                      1. Chloroplast Evolution
                                                                                                                                        1. Nuclear Evolution
                                                                                                                                        2. Multicellularity
                                                                                                                                          1. Colonial Organisms
                                                                                                                                            1. Cell Differentiation
                                                                                                                                              1. Developmental Programs
                                                                                                                                              2. Sexual Reproduction
                                                                                                                                                1. Genetic Recombination
                                                                                                                                                  1. Evolutionary Advantages
                                                                                                                                                  2. Complex Life Forms
                                                                                                                                                    1. Ediacaran Biota
                                                                                                                                                      1. Cambrian Explosion
                                                                                                                                                        1. Vertebrate Evolution
                                                                                                                                                          1. Terrestrial Colonization
                                                                                                                                                        2. Extremophiles and Limits of Life
                                                                                                                                                          1. Temperature Extremes
                                                                                                                                                            1. Hyperthermophiles
                                                                                                                                                              1. Psychrophiles
                                                                                                                                                                1. Adaptation Mechanisms
                                                                                                                                                                2. Chemical Extremes
                                                                                                                                                                  1. Acidophiles
                                                                                                                                                                    1. Alkaliphiles
                                                                                                                                                                      1. Halophiles
                                                                                                                                                                        1. Heavy Metal Tolerance
                                                                                                                                                                        2. Physical Extremes
                                                                                                                                                                          1. High Pressure
                                                                                                                                                                            1. High Radiation
                                                                                                                                                                              1. Desiccation
                                                                                                                                                                                1. Low Nutrients
                                                                                                                                                                                2. Implications for Astrobiology
                                                                                                                                                                                  1. Expanded Habitability Concepts
                                                                                                                                                                                    1. Analog Environments

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                                                                                                                                                                                3. Planetary System Formation and Architecture

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                                                                                                                                                                                5. Habitability and Planetary Environments