The inevitable journey to being

Abstract

Life is evolutionarily the most complex of the emergent symmetry-breaking, macroscopically organized dynamic structures in the Universe. Members of this cascading series of disequilibria-converting systems, or engines in Cottrell's terminology, become ever more complicated—more chemical and less physical—as each engine extracts, exploits and generates ever lower grades of energy and resources in the service of entropy generation. Each one of these engines emerges spontaneously from order created by a particular mother engine or engines, as the disequilibrated potential daughter is driven beyond a critical point. Exothermic serpentinization of ocean crust is life's mother engine. It drives alkaline hydrothermal convection and thereby the spontaneous production of precipitated submarine hydrothermal mounds. Here, the two chemical disequilibria directly causative in the emergence of life spontaneously arose across the mineral precipitate membranes separating the acidulous, nitrate-bearing CO 2 -rich, Hadean sea from the alkaline and CH 4 /H 2 -rich serpentinization-generated effluents. Essential redox gradients—involving hydrothermal CH 4 and H 2 as electron donors, CO 2 and nitrate, nitrite, and ferric iron from the ambient ocean as acceptors—were imposed which functioned as the original ‘carbon-fixing engine’. At the same time, a post-critical-point (milli)voltage pH potential (proton concentration gradient) drove the condensation of orthophosphate to produce a high energy currency: ‘the pyrophosphatase engine’.

Beating the acetyl coenzyme A-pathway to the origin of life

“…The resulting NO may bind to di-iron centres such as are present in green rust minerals coating the outer surface of the FeS-based inorganic membranes [9] where the oxygen atom can be activated by electrons which it extracts from a strongly redox crossed-over Mo/W centre. Such a Mo/W centre, however, does only reduce the oxygen if it can simultaneously dispose of its second, more strongly reducing electron towards a suitable acceptor [8,108].…”

“…Moreover, they have started to acknowledge a further necessary condition for metabolic pathways to emerge, imposed by thermodynamics as pointed out by Schrödinger [6] more than half a century ago and by Boltzmann himself more than a half century before that [7], that is, the need for a strong flow of free energy from the environment which can be coupled to the biomass-producing reactions. Only such a flow of free energy, made productive by being funnelled through coupling devices that convert the dissipation of that free energy to the generation of 'product' free energy embodied in specific chemical disequilibria [8,9], allows a system to evolve towards the structured, low-entropy state called life while, at the same time, obeying the second law of thermodynamics. To avoid confusion and allow us to focus on the key points of carbon fixation that are the subject of this paper, the bioenergetic aspects of the discussion have been framed in largely conventional terms.…”

“…To avoid confusion and allow us to focus on the key points of carbon fixation that are the subject of this paper, the bioenergetic aspects of the discussion have been framed in largely conventional terms. This was done notwithstanding the fact that in the companion paper [9] and a preceding paper [8], it was argued at length that these terms are inappropriate for a correct discussion of bioenergetics, the processes conventionally called 'energy conservation' in particular.…”

Terrestrial aftermath of the Moon-forming impact

“…6) and the serpentine hydrothermal vents (approx. 11) as its energy source [79][80][81][82]. In general, molecular biology studies make inferences on the Hadean Earth environment, here that serpentine was present and that the CO 2 pressure was approximately 1 bar.…”

The sluggish speed of making abiotic methane

“…Low-temperature alkaline hydrothermal systems offer an environment in which there is a strong thermodynamic drive for CO 2 reduction to methane, but substantial kinetic barriers inhibit abiotic completion of this process. Perhaps microbial methanogenesis originated when organisms learned to finish what peridotite started (19,20).…”