Evolution and Biochemical Catalysis

Generally speaking, the chance to establish autocata-lytic cycles during chemical evolution (Orgel 2003) with or without external selecting influences is rather small. On the other hand, some (not all of the) similarities between product patterns of prebiotic simulation experiments and contemporary biochemistry suggest that the principal biochemical structures kept constant throughout the existence of life on Earth. Hence auto-catalytic feedback loops came into existence only later. 

Franzle, Chemical Elements in Plants and Soil Parameters Controlling Essentiality, Tasks for Vegetation Science, vol. 45, 153 

2 A Three-Step-Model for Uptake and Functionalization of Metal Ions Enforced by Chemical Evolution Itself (Bootstrap) 

As was shown before, it is an erroneous assumption that systems (chemical entities) which act as efficient catalysts on other species are given to work in the same manner if integrated into some autocatalytic system. Yet, with autocatalysis - at least as capability for reproduction - being a crucial part of any meaningful definition of life, the rule of three functions must have applied to the most early organisms already quite like it does control essentiality today, regardless of their exact chemical composition. 

This model of events is detailed into some three-step-scenario for better analysis and understanding. It is based on experiments and reasonings by Beck and Ling (1977) and Kobayashi and Ponnamperuma 

---