title: Complex Autocatalysis in Simple Chemistries.
abstract: Life on Earth must originally have arisen from abiotic chemistry. Since the details of this chemistry are unknown, we wish to understand, in general, which types of chemistry can lead to complex, lifelike behavior. Here we show that even very simple chemistries in the thermodynamically reversible regime can self-organize to form complex autocatalytic cycles, with the catalytic effects emerging from the network structure. We demonstrate this with a very simple but thermodynamically reasonable artificial chemistry model. By suppressing the direct reaction from reactants to products, we obtain the simplest kind of autocatalytic cycle, resulting in exponential growth. When these simple first-order cycles are prevented from forming, the system achieves superexponential growth through more complex, higher-order autocatalytic cycles. This leads to nonlinear phenomena such as oscillations and bistability, the latter of which is of particular interest regarding the origins of life.
authors.affiliation: University of Tokyo and Tokyo Institute of Technology.
authors.forename: Nathaniel
authors.initials: N
authors.lastname: Virgo
authors.affiliation: University of Tokyo.
authors.forename: Takashi
authors.initials: T
authors.lastname: Ikegami
authors.affiliation: University of Sussex.
authors.forename: Simon
authors.initials: S
authors.lastname: McGregor
mesh_terms: D002384:Catalysis; D018534:Earth, Planet; D007700:Kinetics; D008954:Models, Biological; D000069497:Origin of Life; D013816:Thermodynamics
keywords: Autocatalysis; chemical kinetics; origin of life; self-organization; thermodynamics