144 Information Storage and Neural Control 



the imperative of Shannon's Theorem 10, and since stabihty is a 

 function of compositional complexity, it follows that a natural 

 tendency of ecological communities should be to develop to maxi- 

 mum proportions within the limitations imposed by particular 

 environments. This conclusion is consistent with empirical ob- 

 servations. 



One measure of the extent to which a given community has 

 expanded to fill a physical space is the total quantity of organic 

 matter contained in that space. This variable will be referred to 

 here as the community's biomass. Because community ontogeny 

 (ecological succession) proceeds by means of niche (17) prolifera- 

 tion (more species make more species possible), a reasonable way 

 to assess, in a quantitative sense, the extent of organization of a 

 community might be to oxidize a suitable sample in a calorimeter 

 and to equate heat evolution with intrinsic complexity. Though 

 admittedly crude, such an approach would not be entirely without 

 basis since all information, even that which is abstract, is under- 

 stood to be physically based and is therefore referable to thermo- 

 dynamic negative entropy (18, 19). This broaches the problem of 

 the relationship between information and energy — the reason why 

 information theory is of interest to energy ecologists. 



ENERGY AS CURRENCY 



The connection between energy and information has been 

 well established in the context of macroscopic thermodynamics 

 (19) where adiabatically accessible system states are generally 

 regarded as informationally equivalent, while those attainable 

 only non-adiabatically are not (20). In the usual Boltzmann- 

 Gibbs treatments, the role of matter in determining a system's 

 entropy is obscure; however, the recently introduced formalism 

 of Jaynes (21) and Tribus (22) offers considerable clarification, 

 as follows. 



Consider a system of /?«, rib, ■ ■ ■ particles of matter of kinds 

 a, b, . . . in a phase space with coordinates Xi, X2, .... When the 

 coordinates are prescribed and the number of particles known, 

 the system consists of a finite number of discrete quantum states, 

 J, with energies e^.- 



