Abstract It is proposed that reactions of the hydrated electron e aq − in the “primordial soup” were an evolutionary pressure which selected biopolyelectrolytes, coacervates, “organelles” and lipid-membrane-bound structures of a pattern found in the biosphere today. The two physical restrictions of e aq − reactivity which determined its evolutionary specificity are (a) its exclusion from polyanion domains in Donman fashion, and (b) its inability to solvate in alkanes. Thus, (1) polyanions (as opposed to polyanions) and (2) lipid-membrane-bound (as opposed to free) structures are protected from e aq − reactivity and degradation. The polyanionic nature of the current biosphere, and the prevalence of anionic polyanion-polycation complexes (such as ribosomes and chromatin), are attributed to (1). (2) co-operated in protecting the products of (1) as salinity in the “primordial soup” increased and (a) was no longer important. The evolution of DNA, and the existence of electron transport mechanisms are seen as logical extensions of the properties of e aq − Experimental evidence is already available to support all the postulated processes.