A Hardware View of Biological Organization

Abstract

This chapter focuses on the nature of the physical ordering principles that presumably were operative in the prebiotic world and played a role in structuring the chemistry of the evolving planet. In looking at biological organization, we must first understand the hardware before we can move to the software. Examining the physics underlying prebiotic chemistry, we see a number of examples of high organization: vesicle formation, electron and proton coupling between chemical reactions, Pauli’s exclusion principle applied to reacting electrons, and the principle of detailed material balances in a stable, recycling system.

Because of the specific strength of earth’s gravity, hydrogen slowly escaped from our atmosphere, thus leading from a reducing to an oxidizing environment. Because of the spectrum of solar radiation, electronic transitions are readily excited. Without external planning, a particular set of reaction networks are naturally selected within such an environment: those involving primarily carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur (CHNOPS). The initially reducing environment favors production of a “primordial oil slick” on the earth’s oceans. This slick is likely to generate amphiphilic molecules that form into bilayer vesicles whose inner aqueous contents can easily differ from its outer aqueous surround. A plausible system for driving synthesis of pyrophosphate in such vesicles is illustrated. In conclusion, it seems that a simple hierarchy of physical organizing features underlies the spontaneous formation of the complex global biosphere, and these physical conditions are now reasonably well understood. —The Editor