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Science 4 June 1999:
Vol. 284. no. 5420, p. 1585
DOI: 10.1126/science.284.5420.1585j
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Quarter-power scaling relations link body mass M with any number of biological variables; for example, the diameters of the tree trunks and aortas scale as M 3/8, cellular metabolism as M -1/4, and the blood circulation time and life-span as M1/4. West et al. (p. 1677; see the news story by Mackenzie) present a generalized explanation for this phenomenon based on the proposal that organisms are sustained by hierarchical fractal-like structures that terminate in size-invariant functional units, and that the surface area for acquisition of resources is maximized while the energy dissipated in the distribution mechanism is minimized. The authors liken the fractal network to a fourth spatial dimension of life.




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