Metabolism First

Arun, writing in the comments to an earlier post, brought my attention to Robert Shapiro's Scientific American cover story on a metabolism first approach to the origin of life. (Subscription only, but a longer, earlier, free version, minus nifty graphics and some other features is here. )

The magic without magic of small molecule cycles is heredity without heredity - actually, a distributed type of heredity. Such a system takes energy from the environment, uses it to drive a chemical cycle which includes producing more of the molecules that participate in the cycle. In effect, such systems create a local negative entropy gradient by exploiting some naturally occuring negative entropy gradient (energy from the Sun, volcanos, lightning, whatever).

Hurricanes perform an analogous feat. Once organized, their ferocious winds very efficiently extract heat from the ocean and use it to drive those same winds. The entropy gradient they exploit is that between the warm ocean below and the cold of the upper atmosphere and cosmos above. One of the biggest enemies of a hurricane is disruption of its organization, for example due to wind shear.

Chemical cycles need to be able to preserve their organization as well, and Shapiro suggests that that requires some sort of compartmentalization. I recommend his article, in the magazine form if you have access, but read the freebee on line if you don't.