(Note: This is Part 12 of Dr. Wadhawan’s series on Complexity. All previous parts of the series can be accessed through the Related Posts list at the bottom of this article.)

According to one model of the origins of life, it is likely that life originated twice, with two separate kinds of organisms, one capable of metabolism without exact replication, and the other capable of replication without metabolism; at some stage the two features came together. Another model is that life originated with the emergence of RNA molecules which could act as both enzymes and self-replicators. In either case, the emergence of self-replicators also marked the first step towards the evolution of consciousness.

12.1 Freeman Dyson’s Dual-Origin Model for Life

Freeman John Dyson is a theoretical physicist and mathematician, well known for his work in quantum field theory, solid-state physics, and nuclear engineering. In 1949 he demonstrated the equivalence of the two formulations of quantum electrodynamics, one by Richard Feynman and the other by Julian Schwinger and Sin-Itiro Tomonaga. In 1985 he wrote a little book Origins of Life, in which he argued that metabolic reproduction and replication are logically separable propositions, and that natural selection does not require replication, at least for simple creatures. In higher-level life as seen today, reproduction of cells and replication of molecules occur together. But there is no reason to presume that this was always the case. According to Dyson, it is more likely that life originated twice, with two separate kinds of organisms, one capable of metabolism without exact replication, and the other capable of replication without metabolism. At some stage the two features came together. When replication and metabolism occurred in the same creature, natural selection as an agent for novelty became more vigorous. Read the full story

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Note: For previous parts to Dr. Wadhawan’s series on complexity check out the ‘Related Posts’ found at the bottom of this article.

How could the blind forces of Nature create large and highly information-laden molecules like DNA and proteins just by random processes? DNA carries information for the synthesis of proteins, but it requires the prior availability of certain protein molecules for performing its genetic duties. Such proteins help the double-helix DNA molecule to uncoil itself and split into two strands for replication purposes. Therefore, DNA and certain proteins must have emerged independently, by some efficient (and therefore reasonably likely) chemical processes. But how? The answer has to do with the chemical evolution of autocatalytic sets of molecules, which could consume energy-rich molecules and other precursors (’food’) to ‘reproduce’. These molecules were the predecessors of proteins and DNA etc., and thence of life.

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