Abstract
While most advances in the study of the origin of life on Earth (OoLoE) are piecemeal, tested against the laws of chemistry and physics, ultimately the goal is to develop an overall scenario for life’s origin(s). However, the dimensionality of non-equilibrium chemical systems, from the range of possible boundary conditions and chemical interactions, renders the application of chemical and physical laws difficult. Here we outline a set of simple criteria for evaluating OoLoE scenarios. These include the need for containment, steady energy and material flows, and structured spatial heterogeneity from the outset. The Principle of Continuity, the fact that all life today was derived from first life, suggests favoring scenarios with fewer non-analog (not seen in life today) to analog (seen in life today) transitions in the inferred first biochemical pathways. Top-down data also indicate that a complex metabolism predated ribozymes and enzymes, and that full cellular autonomy and motility occurred post-LUCA. Using these criteria, we find the alkaline hydrothermal vent microchamber complex scenario with a late evolving exploitation of the natural occurring pH (or Na+ gradient) by ATP synthase the most compelling. However, there are as yet so many unknowns, we also advocate for the continued development of as many plausible scenarios as possible.
Highlights
Explaining the origin of life on Earth (OoLoE) has proven difficult, primarily because even the simplest organisms today have an enormously complex hierarchical organization, with intricate interdependencies between their various internal functions, the pathways that enable them, and their spatially and temporally changing external environments
The most comprehensive scenarios have been developed for the alkaline hydrothermal vent microchamber [16] and green rust mound [17] venues, hydrothermally charged marine sediments [18,31], and associated with terrestrial geothermal hot springs [20,21]
In support of the supposition that the Bacteria and Archaea independently cellularized, we note that they have non-homologous locomotory structures, flagella in Bacteria and archaella in Archaea [66], where for example, Bacteria use proton motive force to drive the rotation of their flagella, while Archaea use adenosine triphosphate (ATP) to drive the rotation of their archaella
Summary
Explaining the origin of life on Earth (OoLoE) has proven difficult, primarily because even the simplest organisms today have an enormously complex hierarchical organization, with intricate interdependencies between their various internal functions, the pathways that enable them, and their spatially and temporally changing external environments. These difficulties are compounded by the fact that life probably arose by 4 billion years ago on a very different Earth and that we only have data from one origin. While we are not concerned here with life elsewhere in the universe, we note that the burgeoning field of astrobiology has injected enormous energy into the study of the origin of life, with 119,000 Google Scholar search results from 2001–2020
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
