Scaling Laws

Geoffrey B. West and James H. Brown discovered that allometric 
'''scaling laws''', including the 3/4 power law for metabolic rates, 
are characteristic of all organisms.
One factor which increases biological diversity is body size,
which varies over 21 orders of magnitude in biological organisms.
Yet some universal rates and regular relationships stay constant.
The metabolic rate of biological life-forms scales approximately as 
the 3/4-power of mass from complex molecules up to the largest 
multicellular organisms.

Similarly, time-scales (such as lifespans and growth-rates) and 
sizes (such as genome lengths, RNA densities, and tree heights) 
scale as power laws with exponents which are typically simple 
multiples of 1/4.
West and Brown have shown that these 1/4 power scaling laws
follow from underlying principles embedded in the dynamical 
and geometrical structure of space-filling, fractal-like, 
hierarchical branching networks.

These scaling laws can be applied to artificial structures as
well. Like biological systems, counties and cities have evolved 
branching networks that transport a variety of resources.

== Links ==

* Wikipedia Entry for [http://en.wikipedia.org/wiki/Power_law Power Law]

== Papers ==

* Geoffrey B. West, James H. Brown, and Brian J. Enquist [http://biology.unm.edu/jhbrown/Documents/Publications/WestBrown&Enquist1997S.pdf A General Model for the Origin of Allometric Scaling Laws in Biology], Science Vol 276 April (1997) 122-126

* Geoffrey B. West and James H. Brown, [http://biology.unm.edu/jhbrown/Documents/Publications/West&Brown2004PT.pdf Life's Universal Scaling Laws], Physics Today, September (2004) 36-42

[[Category:Basic Principles]]