I am reading a fascinating paper, "Scale-free networks in cell biology", by Reka Albert at Penn State, and thought some might be interested in it.
Scale-free networks are a sub-type of "small world" networks, which show up in all kinds of biological and social systems, among other places. As it turns out, the metabolic network in a cell is a scale-free small world network (as are movie actors – see Kevin Bacon Number)
What makes this interesting (aside from being an intriguing glimpse into the details of what goes on in a cell) is that networks that have these characteristics tend to be ’emergent’, that is, they develop naturally out of certain types of processes. Such processes tend to have very simple local rules that somehow generate complex global behaviors. And, one of the biggest open questions in the search for the origin of life is how something ascomplex as a metabolic network could have formed, for it seems that too many pieces would have to be in place all at once. So there may be a clue to that puzzle here.
There is also the question of why life, which tends to work against the second law of thermodynamics in a local fashion, climbing high up the entropy hill, as it were, came about as non-living systems tend to fall apart, not get more organized. Some of the reading I’ve been doing indicates that that certain types of networks self-organize around an energy flow in such a way as to use the complexity to dissipate energy more efficiently. A more efficient energy dissapation mechanism would increase entropy faster, and thus this strong pull down the entropy hill could be what provided the drive for living systems to get organized.
These self-organizing networks exhibit dynamic ‘signatures’ that may resemble those emerging from these small world networks. This paper caught my eye as one that might provide some clues about this possible connection.
Boy, I sure do wish I could figure out a way to get paid to
do this …