The Transition from Abiotic Chemistry to Cellular Life

Slowly step by step science is finding out how life got started. This paper about the metabolism of early organisms caught my eye, especially that bit.

The earliest form of carbon fixation identified by scientists achieved a special kind of built-in robustness -- not seen in modern cells -- by layering multiple carbon-fixing mechanisms. This redundancy allowed early life to compensate for a lack of refined control over its internal chemistry, and formed a template for the later splits that created the earliest major branches in the tree of life.

So I take it, basically these early organisms had two metabolic pathways – let's call them "1" and "2". Pathway 1 took precursor molecule A and converted it (with the help of energy) into something useful for the organism – and pathway 2 did that the same with precursor molecule B. Now, as the "refined control" was missing in that early stage of life, the organism had to take what was available. Precursor molecule A is available? Use pathway 1! Precursor molecule B is available? Use pathway 2!