Natural conventions

We conclude that, during postchemical evolution, what was taking place was not only a development of metabolic structures, but also an evolution of coding rules, of natural conventions. The true mechanism of postchemical evolution, in other words, was not genetic drift alone, but a combination of drift and natural conventions. To the classical concepts of evolution by genetic drift and by natural selection, we must add therefore the concept of evolution by natural conventions. 

It is important to notice that this is very different from the mechanism of chemical evolution. Kauffman and Dyson, it will be remembered, have shown that the probability of a spontaneous transition from chaos to order increases with the complexity of the system, but in this case the order (or antichaos) is not a result of natural conventions and has nothing to do with organic codes. 

This tells us that chemical evolution was really different from postchemical evolution. In the course of chemical evolution, the jump of primitive metabolic systems from chaos to order was only a question of statistical probability and energy conditions. During postchemical evolution, instead, a new type of antichaos appeared, an order that was based on conventional rules of correspondence between two independent molecular worlds, and it was from these first natural conventions that the genetic code finally emerged. 

We conclude that dynamic instability is a means of creating an endless stream of cell types with only one common structure and with the choice of a few anchoring molecules. But this is possible only because there is no necessary relationship between the common structure of the cytoskeleton and the cellular structures that the cytoskeleton is working on. The anchoring molecules (or accessory proteins) are true adaptors that perform two independent recognition processes microtubules on one side and different cellular structures on the other side. The resulting correspondence is based therefore on arbitrary rules, on true natural conventions that we can refer to as the cytoskeleton codes. 

The crucial point is that there is no necessary correspondence between protein signals and geographic destinations. The export-to-the-nucleus signals, for example, could have been used for other compartments, or could have been totally different, just as the names which are given to cities, to airports and to holiday resorts. The existence of eukaryotic compartments, in conclusion, is based on natural conventions, and to these rules of correspondence we can legitimately give the name of compartment codes. 

The origin and the evolution of life took place by natural selection and by natural conventions. The great events of macroevolution have always been associated with the appearance of new organic codes. ... 

But they haven t looked deep enough, and above all they have looked for biological features in cultures, not for cultural (conventional) features in biology. Indeed, if life evolved not only by natural selection but also by natural conventions, then at the deepest level of all, at the very heart of fundamental change, there would be codes in life as there are codes in culture. Which would mean, among other things, that cultures are indeed supraorganismal wholes as species are. 

Barbieri s most ambitious claim is that life evolves through natural conventions as well as natural selection. The importance of such conventions as major evolutionary innovations becomes increasingly... 

Heinz-Giinther Wittmann and Elmar Zeitler allowed me to perform the experimental research which led me first to the concept of ribotype and then to the idea of evolution by natural conventions. 

In order to use in practice this definition, it must also be decided which one of the nested sums will be considered the innermost. That is the first index of vector k which is to be incremented in a first place. Here, in the present paper is followed the natural convention, this will be supposed to hold for the n-th sum symbol or same to say for the k vector n-th index. Therefore, being the first vector index associated to the outermost nested sum, then it will be connected to the last index to suffer increment. 

Natural convection - L Secondary transients Natural convention - L Loss of electric sources Battery power - R Total loss of heat sink Passive DHR to the air and ground - S Station blackout Not critical ... 

In accidents, heat removal is accomplished through natural convention of all media in all systems. The residual heat is removed to the surrounding air by the RHRS. 

Dilution ventilation utilises natural convention through open doors, windows, roof ventilators etc. or assisted ventilation by roof fans or blowers which draw or blow in fresh air to dilute the contaminant. With both of these systems the problem of providing make-up air at the proper temperature, especially during the winter months, has to be considered. 

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