Abiogenesis, Miller-Urey, RNA-world, metabolism-first, hydrothermal-vent origin, LUCA, astrobiology.
Origins Of Life
Abiogenesis
Origin of life from non-living matter. Must explain: compartment (protocell), metabolism (auto-sustaining reaction network), replication…
Miller-Urey experiment
1953 spark-discharge synthesis of amino acids from CH4 + NH3 + H2 + H2O. Showed prebiotic organic synthesis is plausible under…
RNA world hypothesis
Gilbert 1986: early life used RNA as both genetic material + catalyst (ribozymes). Supported by ribosomal peptidyl-transferase being…
Metabolism-first hypothesis
Self-sustaining chemical reaction networks (autocatalytic cycles) preceded genetic replication. Wächtershäuser's iron-sulfur world;…
Alkaline-hydrothermal-vent origin
Russell-Martin: pH gradient across FeS mineral boundaries at alkaline vents (Lost City) mimics chemiosmotic gradient, could drive protocell…
Last Universal Common Ancestor (LUCA)
Inferred most-recent common ancestor of all extant cellular life (~3.5-4.0 Gya). Had translation, DNA, core metabolism; habitat debated…
Drake equation
N = R* · fp · ne · fl · fi · fc · L — estimated number of communicative civilisations in Milky Way. Each factor highly uncertain; framework…
Oparin-Haldane hypothesis
1920s proposal that primitive reducing atmosphere + UV + lightning formed organic molecules → 'primordial soup'. Framework for Miller-Urey…
Ribozyme as RNA-world relic
Modern catalytic RNAs (ribosomal peptidyl transferase, self-splicing introns, RNase P) preserve evidence for an earlier RNA-catalysed…
Protocell
Membrane-bound lipid vesicles that grow, divide, and encapsulate replicators. Fatty-acid bilayers can self-assemble; Szostak lab models…