Are Biological Systems Poised at Criticality?
Abstract
Many of life's most fascinating phenomena emerge from interactions among many elements—many amino acids determine the structure of a single protein, many genes determine the fate of a cell, many neurons are involved in shaping our thoughts and memories. Physicists have long hoped that these collective behaviors could be described using the ideas and methods of statistical mechanics. In the past few years, new, larger scale experiments have made it possible to construct statistical mechanics models of biological systems directly from real data. We review the surprising successes of this "inverse" approach, using examples from families of proteins, networks of neurons, and flocks of birds. Remarkably, in all these cases the models that emerge from the data are poised near a very special point in their parameter space—a critical point. This suggests there may be some deeper theoretical principle behind the behavior of these diverse systems.
 Publication:

Journal of Statistical Physics
 Pub Date:
 July 2011
 DOI:
 10.1007/s1095501102294
 arXiv:
 arXiv:1012.2242
 Bibcode:
 2011JSP...144..268M
 Keywords:

 Critical point;
 Maximum entropy model;
 Biological networks;
 Proteins;
 Collective behavior;
 Quantitative Biology  Quantitative Methods;
 Condensed Matter  Disordered Systems and Neural Networks;
 Condensed Matter  Statistical Mechanics;
 Nonlinear Sciences  Adaptation and SelfOrganizing Systems;
 Physics  Biological Physics
 EPrint:
 21 pages