Complexity Explorer Santa Fe Institute


Scaling Laws In Biology And Other Complex Systems

"Life is very likely the most complex phenomenon in the Universe manifesting an extraordinary diversity of form and function over an enormous range. Yet, many of its most fundamental and complex attributes scale with size in a surprisingly simple fashion. For example, metabolic rate (the power required to sustain the system) scales as approximately the 3/4-power of mass over 27 orders of magnitude from molecular levels up to the largest multicellular organisms. Similarly, time-scales, such as lifespans and growth-rates, increase with exponents which are typically simple powers of 1/4. It will be shown how these universal quarter-power scaling laws follow from fundamental generic principles embedded in the dynamics and geometry of underlying networks, leading to a general quantitative theory that captures essential features of many diverse biological systems. Examples will include animal and plant vascular systems, growth, cancer, aging and mortality, sleep, DNA nucleotide substitution rates. These ideas will be extended to discuss social organisations such as cities and firms: to what extent, if at all, can we think of these as very large organisms and therefore as an extension of biology? Analogues to metabolic rate and behavioral times in cities scale counter to their behaviour in biology. Driven by innovation and the creation of wealth this has dramatic implications for their growth, development, sustainability and pace of life which, left unchecked, potentially sow the seeds for their collapse. Geoffrey West is a theoretical physicist whose primary interests have been in fundamental questions in physics, especially those concerning the elementary particles, their interactions and cosmological implications. Prior to joining the Santa Fe Institute as a Distinguished Professor in 2003, he was the leader, and founder, of the high energy physics group at Los Alamos National Laboratory, where he is one of only approximately ten Senior Fellows."

Google Tech Talk
West, G.
complex systems; complexity of cities; 3/4 power law; scalability; metabolic growth;

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