Energetics of the First Life (original) (raw)

Life can exist only when supported by energy flow(s). Here, the tentative mechanisms of coupling between the natural energy fluxes and the first life forms are discussed. It is argued that the evolutionarily relevant, continuous fluxes of reducing equivalents, which were needed for the syntheses of the first biomolecules, may have been provided by the inorganic photosynthesis and by the redox reactions within hot, iron-containing rocks. The only primordial environments where these fluxes could meet were the continental geothermal systems. The ejections from the hot, continental springs could contain, on the one hand, hydrogen and carbonaceous compounds and, on other hand, transition metals as Zn and Mn, which precipitated around the springs as photosynthetically active ZnS and MnS particles capable of reducing carbon dioxide to diverse organic compounds. At high pressure of the primordial CO 2 atmosphere, both the inorganic photosynthesis and the abiotic reduction of carbon dioxide within hot rocks should have proceeded with high yield. Among a plethora of abiotically produced carbonaceous molecules, the natural nucleotides could accumulate as the most photostable structures; their polymerization and folding into double-stranded segments should have been favored by the further increase in the photostability. It is hypothesized that after some aggregates of photo-selected RNA-like polymers could attain the ability for self-replication, the consortia of such replicating entities may have dwelled in honeycomb-like ZnS-enriched mineral compartments which provided shelter and nourishment. The energetics of the first life forms could be driven by their ability to cleave the abiogenically formed organic molecules and by reactions of the phosphate group transfer. The next stage of evolution may be envisaged as a selection for increasingly tighter envelopes of the first organisms; this selection may have