By DR. VINOD K. WADHAWAN - NIRMUKTA
Added: Sat, 26 Dec 2009 00:00:00 UTC

http://nirmukta.com/2009/12/25/complexity-explained-12-the-likely-origins-of-life/

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.
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http://nirmukta.com/2009/12/25/complexity-explained-12-the-likely-origins-of-life/

TAGGED: BIOLOGY, EVOLUTION, SCIENCE