The Evolution of Complexity - Abstracts.

The Gaia theory: Role of microorganisms in planetary information network

By Anton Markos

Abstract:

The central point of the Gaia theory lies in the realization that it is life that has maintained the planetary thermostat and chemostat over 3.5 eons of evolution. The whole globe can be viewed as a self-evolving entity. Bacteria play a principal role in this formative process. This line of thinking should answer several principal questions: Is the biosphere simply a set of essential- selfish individuals, each testing its fitness? Is memory in the biosphere confined to genes? Is the composition of ecosystems and their behavior only kind of dynamic equilibrium? Or is there a huge amount of epigenetic information that enables organisms to interpret properly their situation and behave accordingly? I state that the information flow, rather than pure thermodynamics plus natural selection, enables living beings not only to "read" their environment, interpret their situation and behave accordingly to this understanding, but also to establish geophysiology, to become part of Gaia. This flow comprises genes as well as signals, both diffusible as well as permanent. From an analogy with the situation in the multicellular organism I suggest three types of information mediators inside the body of Gaia:

1. Ultrastructure. The existence of tissues in a multicellular body is, dependent on the cells themselves as well as on the intricate 3D dynamical network of extracellular matrix, comprising thousands of organic macromolecules and/or minerals, that provides cells with spatial and temporal cues. The structural complexity of microbial communities has also been recognized, but so far has not attracted much attention.
2. Diffusible signals. A plethora of signalling molecules has been described in bacteria. Almost nothing is, however, known about interspecies communication by this means. Structural similarity of signalling molecules derived from different species suggests, however, that such communication indeed takesplace.
3. Gene flux. In frames of neoderwinian paradigm cells in a multicellular body cooperate because they share the same genes, and by mutual action ensure their transfer to the progeny. In contrast to this, each individual and species behave "selfishly" in the sense that they do not care how successfully other individua or species transfer their own genes to the progeny. Bacteria, however, can readilly pick up foreign and thus share a common, global gene pool.

With a shared gene pool, intricate ultrastructure and quickly diffusible signals it is, on my opinion, legitimate to consider Gaia as a superorganism with an "ontogeny" that is identical to its evolution.