Geoffrey B. West
Santa Fe Institute, Santa Fe, USA
Universal Scaling Laws in Biology From Genomes to Ecosystems.
Towards a Quantitative Unifying Theory of Biological Structure and Organization
Despite its extraordinary diversity and complexity, many of life's most fundamental and complex phenomena scale with size in a surprisingly simple fashion. For example, basal metabolic rate scales approximately as the 3/4-power of mass over 27 orders of magnitude from molecular and intra-cellular levels up to the largest multicellular organisms. Similarly, time-scales (such as lifespans and growth-rates) and sizes (such as bacterial genome lengths, RNA densities, and tree heights) scale as simple power laws with exponents which are typically simple multiples of 1/4.
The universality and simplicity of these relationships suggest that fundamental constraints underly much of the coarse-grained generic structure and organisation of living systems. It will be shown how these scaling relationships follow from underlying principles embedded in the dynamical and geometrical structure of space-filling, fractal-like, hierarchical branching networks, presumed optimised by natural selection.
These ideas lead to a general quantitative, predictive theory that potentially captures the essential features of many diverse biological systems. Examples will include animal and plant vascular systems, growth, cancer, aging and mortality, sleep, cell size, genome lengths, DNA nucleotide substitution rates and the concept of a universal molecular clock. Considerations of temperature and the role of invariants will be discussed.
- Date/Time: Wednesday, 7 May 2008, 14:00 – 16:00 h
- Place: ETH Zürich, HG G 60
Size matters! Growth, Innovation and the Pace of Life: is it Sustainable?
A general framework that has been successfully developed for understanding "universal" scaling laws across an extraordinarily wide spectrum of biological phenomena from cells to ecosystems will be extended to social organisations in an attempt to reveal general principles of organization, structure and dynamics. Almost all physiological traits, including fundamental quantities such as metabolic rates, lifespans, growth and evolutionary rates, scale as simple power laws whose exponents are typically simple multiples of 1/4. These have their origin in generic physical and geometric properties of the networks that sustain life, leading to a general quantitative, predictive theory that captures the essential features of many diverse biological systems.
We shall show that analogous scaling laws are manifested in social organisations, suggesting that there are general principles of organization, structure and dynamics common, for example, to all cities reflecting a "universal" underlying social network structure.
We shall address questions such as: are social organisations "just" an extension of biology, and to what extent is a city, for example, a very large organism?
These scaling laws have dramatic implications for growth, the pace of life, development and sustainability: innovation and wealth creation that fuel social systems, if left unchecked, potentially sow the seeds for their inevitable collapse.
- Date/Time: Tuesday, 6 May 2008, 13:00 – 13:45 h
- Place: ETH Zürich, RZ F 21, Clausiusstrasse 59