12/28/2022 0 Comments Importance of tidal pools in evolutionSadly, this is not possible, but if it were, we would remind him of our conversations in which he proposed that using methods of combinatorial chemistry would be an efficient way for origins of life research to advance, to which we would heartily agree! However, we would also state that it is a way for self-assembled chemical systems to advance in a cyclic process toward the complexity required for life to begin. It would be an enjoyable exercise to debate the point Leslie made in the quote above (Orgel, 2000). One of the authors knew Leslie Orgel quite well, and the clarity of his thinking has guided our research in many ways. We conclude by utilizing the hypothesis to posit where life might also have emerged in habitats such as Mars or Saturn's icy moon Enceladus. We compare the oceanic vent with land-based pool scenarios for an origin of life and explore their implications for subsequent evolution to multicellular life such as plants. A roadmap to future testing of the hypothesis is presented. A continuity is observed for biogenesis beginning with simple protocell aggregates, through the transitional form of the progenote, to robust microbial mats that leave the fossil imprints of stromatolites so representative in the rock record. The scenario is then placed in a geological setting on the early Earth to suggest a plausible pathway from life's origin in chemically optimal freshwater hot spring pools to the emergence of microbial communities tolerant to more extreme conditions in dilute lakes and salty conditions in marine environments. Laboratory and field experiments testing the first steps of the scenario are summarized. Progenote populations can undergo selection and distribution, construct niches in new environments, and enable a sharing network effect that can collectively evolve them into the first microbial communities. We propose that protocells aggregating into a hydrogel in the intermediate moist phase of wet-dry cycles represent a primitive progenote system. Drawing on metaphors from the bootstrapping of a simple computer operating system, we show how protocells cycling through wet, dry, and moist phases will subject polymers to combinatorial selection and draw structural and catalytic functions out of initially random sequences, including structural stabilization, pore formation, and primitive metabolic activity. The hypothesis is based on experimental evidence that lipid-encapsulated polymers can be synthesized by cycles of hydration and dehydration to form protocells. We present a testable hypothesis related to an origin of life on land in which fluctuating volcanic hot spring pools play a central role.
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