New Criticals

If we combine these last two ideas, that catalysis is the basis for non-equilibrium distributions of matter and that cycles are a necessary condition for dissipation in a closed system, we arrive at the idea the idea that the abiotic progenitors of living organisms were catalytic cycles. This is widely accepted in the origins literature but that doesn't mean that everyone agrees on why some type of catalytic cycle must have emerged before proper organisms or the emergence of a genetic code. In a future post we will contrast Eigen and Schuster's quasi-species theory with Jeffrey Wicken's proposed minimal autocatalytic cycle. Much of the debate hinges on whether one identifies energy processing or replication as the defining rationale of living organization. I'm sure you know which side I'm on, but before we can properly attack the gene-machine conception of organisms we need some more chemical details.

The raw material of molecular complexity produced through entropic randomization becomes information once a structure plays a catalytic role in a dissipative cycle. This is because henceforth, the molecule exists not because of its own thermodynamic stability or due to the randomizing tendencies of a system to produce new configurations, instead it exists because the cycle produces more entropy than the activity of the parts alone ever could. It is now part of a new thermodynamic whole which gains its identity by participation in a pattern of entropy production. Entropy production is thus the rationale which selects cycles over randomly distributed chemical transformations. Those cycles which produce the most entropy by definition also pull the most energy flux into themselves along with the most material resources.

Based on these considerations, we see that the thermodynamic view of evolution sees selection as operating well before the emergence of replication or the genetic code. Later on we will see that it also operates above the level of genes as well. This is because the second law operates at every level of the organic hierarchy, from the formation of atoms to flows of capital. Next time we will continue our discussion of catalytic cycles by introducing some simple concepts from information theory and discussing cycle selection in the context of pre-biotic evolution.

Thumbnail image is from here.