Environmental conditions drive self-organization of reaction pathways in a prebiotic reaction network.

The evolution of life from the prebiotic environment required a gradual process of chemical evolution towards greater molecular complexity. Elaborate prebiotically relevant synthetic routes to the building blocks of life have been established. However, it is still unclear how functional chemical systems evolved with direction using only the interaction between inherent molecular chemical reactivity and the abiotic environment. Here we demonstrate how complex systems of chemical reactions exhibit well-defined self-organization in response to varying environmental conditions. This self-organization allows the compositional complexity of the reaction products to be controlled as a function of factors such as feedstock and catalyst availability. We observe how Breslow's cycle contributes to the reaction composition by feeding C2 building blocks into the network, alongside reaction pathways dominated by formaldehyde-driven chain growth. The emergence of organized systems of chemical reactions in response to changes in the environment offers a potential mechanism for a chemical evolution process that bridges the gap between prebiotic chemical building blocks and the origin of life.