Origin of Evolution versus Origin of Life: A Shift of Paradigm

Abstract

The question of the primordial ancestor must be approached through the search for the origin of evolution, not through the search for the origin of life. There is a major issue with the concept of life because it is impossible to define, thus is not a scientific but a metaphysical concept. On the contrary, evolution may be defined by as few as three conditions. These do not necessarily involve biopolymers. However, such an approach must give clues to explain the emergence of distinct lineages to allow Darwinian natural selection. A plausible solution exists within an autotrophic lipidic vesicle-based model that is presented. The model requires the existence of hydrothermal sites such as the Lost City Hydrothermal Field leading to specific constraints. For this reason Mars and Europa may be questioned as possible cradles of evolution. If we replace the search for the origin of life by the one for the origin of evolution our priority first is to find a consensus on the minimal conditions that would allow evolution to emerge and persist anywhere in the universe.

Origin of life: LUCA and extracellular membrane vesicles (EMVs)

“…Vesicles with membranes composed of bi-layers from mixtures of amphiphilic and hydrophobic molecules could have formed from the organic compounds present locally at high concentrations. However, the stability of bilayer lipidic membranes at high Origin of life 11 pressure and temperature is questionable as bilayers formed of simple amphiphiles are extremely fragile at high pH, ionic strength and high temperatures (Deamer et al 2002;Maurer et al 2009;Tessera 2011). Recent work by a team of researchers at the University of Strasbourg (France) provides a credible scenario for the origin of life.…”

“…Lipidic vesicle models require specific conditions allowing the vesicles to emerge and persist long enough, including a continuous flow of matter and energy and the possibility for the waste products to be diluted in an open milieu so that the system is not hindered by their increasing concentration (Tessera 2009(Tessera , 2011. The serpentinite-hosted Lost City Hydrothermal Field (Kelley et al 2005) is a place that has all these conditions.…”

Coenzyme world model of the origin of life

“…The next class of theories known as “lipid-world” is based on the idea that lipid-like molecules played the key role in the origin of life (Segre et al, 2001; Segre et al, 1998; Serge et al 2001; Tessera, 2011). These models are certainly more realistic than the RNA-world or protein-world models because (1) they consider a spatially heterogeneous system of lipid compositional assemblies in water, (2) lipids do not require coding, (3) lipid surfaces and their individual molecular components have catalytic activity, and (4) the dynamics of compositional assemblies depends on affinity and binding, which are common features in lipids.…”

“…Besides stability, heredity has to support evolvability, which is a capacity to change and keep the changed state recursively across generations. Thus, the origin of life means the emergence of heredity and evolvability rather than the origin of nucleic acids or proteins (Jablonka and Szathmáry, 1995; Tessera, 2011). …”

Marginal stability in chemical systems and its relevance in the origin of life

“…This notwithstanding, abiogenesis is still deeply enigmatic. The definition of life is not easy, but generally the feature distinguishing entities involved in abiogenesis is their ability to replicate and undergo Darwinian evolution [1]. The presence of this feature ensures that the entity has overcome a given complexity threshold, after which it can give rise to even increasingly complex offsprings, until the complexity of the forms of life that we observe today is reached.…”