Monday, June 2, 2008

Ocean floor origin of life

A while back I was wondering how dynamic the Precambrian global genome might have been. I since read a discussion at Pandas Thumb (reveiwing a new Origin of Life site, link on left) where it is suggested that the global genome may have evolved fairly sluggishly until metazoans started having sex. The Precambrian bugs supposedly reproduced very slowly and concentrated their energies on DNA repair. Hmmm, that sounds a lot like those primitive archaea found living deep below the surface last week. So is a deep ocean origin of life gaining currency? Well this latest report seems to bolster the concept further. From the article: “We scratched our heads about what was supporting this high level of growth when the organic carbon content is pretty darn low," Edwards said. Perhaps, the researchers figured, chemical reactions with the rocks themselves might offer fuel for life. Lab tests confirmed the idea.”
This article doesn’t mention the nature of these reactions but we already know of bacteria that can live off the energy released by breaking down various minerals.
I suspect we will find more evidence to support the deep ocean origin of life. In the early earth the bottom of the ocean would have been the most hospitable environment available and electromagnetic radiation too intense to be used as a source of energy as it is now. The complex chemical reactions that underpin photosynthesis have their origin in the simpler chemistry utilised by the bottom dwellers.
My view is that life began as a sort of skein of rich ooze covering vast areas of the Archean sea floor where simple reactions and flow of resources slowly changed and became more complex until at some point Dawkins’ replicators appeared, not just in one spot but simultaneously at many points. Life is flow, of information, energy and resources and it has always been a network. It still is, and the ancient roots of it live on, and are only now being brought to the surface.

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