Classes: primordial soup (Miller–Urey 1953); RNA world (self-replicating ribozymes); metabolism-first (acetyl-CoA / hydrothermal-vent chemistry, Wächtershäuser); lipid-world; panspermia. No consensus; all face 'chicken-and-egg' structure.
Classes: primordial soup (Miller–Urey 1953); RNA world (self-replicating ribozymes); metabolism-first (acetyl-CoA / hydrothermal-vent chemistry, Wächtershäuser); lipid-world; panspermia. No consensus; all face 'chicken-and-egg' structure.