Is pre-Darwinian evolution plausible?

Abstract

BackgroundThis essay highlights critical aspects of the plausibility of pre-Darwinian evolution. It is based on a critical review of some better-known open, far-from-equilibrium system-based scenarios supposed to explain processes that took place before Darwinian evolution had emerged and that resulted in the origin of the first systems capable of Darwinian evolution. The researchers’ responses to eight crucial questions are reviewed. The majority of the researchers claim that there would have been an evolutionary continuity between chemistry and “biology”. A key question is how did this evolution begin before Darwinian evolution had begun? In other words the question is whether pre-Darwinian evolution is plausible.ResultsStrengths and weaknesses of the reviewed scenarios are presented. They are distinguished between metabolism-first, replicator-first and combined metabolism-replicator models. The metabolism-first scenarios show major issues, the worst concerns heredity and chirality. Although the replicator-first scenarios answer the heredity question they have their own problems, notably chirality. Among the reviewed combined metabolism-replicator models, one shows the fewest issues. In particular, it seems to answer the chiral question, and eventually implies Darwinian evolution from the very beginning. Its main hypothesis needs to be validated with experimental data.ConclusionFrom this critical review it is that the concept of “pre-Darwinian evolution” appears questionable, in particular because it is unlikely if not impossible that any evolution in complexity over time may work without multiplication and heritability allowing the emergence of genetically and ecologically diverse lineages on which natural selection may operate. Only Darwinian evolution could have led to such an evolution. Thus, Pre-Darwinian evolution is not plausible according to the author. Surely, the answer to the question posed in the title is a prerequisite to the understanding of the origin of Darwinian evolution.ReviewersThis article was reviewed by Purificacion Lopez-Garcia, Anthony Poole, Doron Lancet, and Thomas Dandekar.

Ribose Selected as Precursor to Life

“…Using genomic and fossil evidence, the possibility of a very early origin of life was described by Betts et al (2018). Pre-Darwinian evolution refers to chemical evolution, whereas Darwinian evolution corresponds to the encoded genetic information upon which the natural selection acts (Tessera, 2018). This definition is not taking into consideration that Darwinian evolution is not equal to biological evolution as often selection is overridden by nonselective factors such as growing populations of small size and varying trait composition.…”

Origin of Life: The Point of No Return

“…The mechanism of Darwinian evolution is the key to understanding the initial complex that triggers the origin of life. Darwinian evolution is a well understood phenomenon in terms of genetic variations, natural selection, heredity, and mathematical modeling, as has been shown many times [6][7][8][9][10][11][12][13]. The task here is to define the minimum number of components working on the molecular level necessary for selection to occur, so these might be utilized in the further origin of life research.…”

“…Currently, there are numerous scenarios for the origin of life emphasizing different "first-appeared" events. Theoretical analyses of some scenarios with respect to Darwinian evolution were already published [10].…”

“…Here, the author would like to utilize the formulated mechanism described in Figure 1 for some of the origin of life ideas. In the list analyzed by Tessera, we find: Metabolism-first scenarios (few variants), Replication-first scenario (the RNA world hypothesis with some modifications but without RNA-peptide world scenarios), and the combined metabolism-replicator scenarios based on eight different criteria [10].…”

“…It has been proposed that self-assembled autocatalytic and autonomous networks of prebiotic chemical species could evolve to produce more stable systems [10,16,[18][19][20][57][58][59][60][61][62]. Usually, those suggestions explain not only the prebiotic synthesis of RNA and amino acids, but the transfer of information and heredity as a necessary byproduct.…”