Origin of life

It seems reasonable that in order to discuss, much less discover, the Origin of life one must first answer the question, "What is Life?" Yet, as discussed in the article, Life, we should pose that question more coherently by asking, "What processes give rise to the activity of living?" In searching for the origin of life, we need to search for the beginnings of the physico-chemical processes that we know underpin the activity of living and how those led to the first cells, the basic building blocks and working units of all living things. Indeed we must search for the characteristics of the cell — the last universal common ancestor cell — from which all current living things descended, remembering that that cell may have descended with modification from an earlier cell of different characteristics. Because we must work backward to a time nearly four billion years ago, we will find little in the way of remains to examine. We can hypothesize, and submit those hypotheses to existing knowledge of earth's early conditions and to experiments attempting to reproduce those conditions. We can narrow our hypotheses and search-paths by dissecting out the most basic and essential physico-chemical process common to all known living things — the universal biophysics and biochemistry of living things — because as conserved core processes they have the greatest probability of embryonic status. We search for the origin of a system we recognize as living in virtue that it has the informational content and information-processing ability to remain in a near steady-state as a self-organized system of hierarchical robust modular biochemical networks, where the networks work autonomously in their own behalf, to offset responses to perturbations, and facilitate the system's reproducing itself. We search for the origin of a system enabled by influx of energy and matter and by a more than compensatory efflux of waste (disorder), thereby sustaining and exploiting a state far from the equilibrium state of randomness. Finally, we search for the origin of a system capable, through its self-reproductive ability, of participating in the evolutionary processes that enable transgenerational evolution of the species to which it belongs in adapting to changing environments.

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Pre-replicator chemical evolution

Pre-biotic pre-replicator chemical evolution as prelude to origin of living systems. See, for example:

• Dyson 1982
• Post 1990
• Galimov 2004 --Anthony.Sebastian (Talk) 12:16, 8 April 2007 (CDT)

Also:

• Danchin 2007

• Sayer 2006

• Deamer 2006

• Szathmary 2006

• Davies 2000 --Anthony.Sebastian (Talk) 12:16, 8 April 2007 (CDT)

References

External links

• Geological timescale.

• Origins of the Eukarya.

• Hadean Eon

Further reading

• Vetsigian, K et al. (2006) Collective evolution and the genetic code Proc Natl Acad Sci USA 103:10696–1070. PMID 1681888

• Goldenfeld N Woese C (2007) Essays: Connections. Biology's next revolution The emerging picture of microbes as gene–swapping collectives demands a revision of such concepts as organism, species and evolution itself. Nature 445:369 (25 January 2007) doi:10.1038/445369a

• Forterre P (2006) Three RNA cells for ribosomal lineages and three DNA viruses to replicate their genomes: A hypothesis for the origin of cellular domain PNAS 103:3669-3674

• Davies P. (2000) The Fifth Miracle: Search for the Origin and Meaning of Life. Simon & Schuster ISBN 978-0684863092
  

• From The New York Times Book Review, by Lee Smolin: "If you are going to read only one book on the origin of life, seriously consider this one. From Scientific American: "His thesis is that 'the first terrestrial organisms lived deep underground, entombed within geothermally heated rocks in pressure-cooker conditions.' Davies also looks at the theories that life began by chemical assembly in a watery medium and that it came to the earth from space in the form of already viable microbes--the panspermia hypothesis.

See also

• Life