In a critically self-organized model of punctuated equilibrium, boundaries determine peculiar scaling of the size distribution of evolutionary avalanches. This is derived by an inhomogeneous generalization of standard branching processes, extending previous mean field descriptions and yielding v = 1/2 together with T’ = 7/4, as distribution exponent of avalanches starting from species at the ends of a food chain. For the nearest neighbor chain one obtains numerically T’ = 1.25 ± 0.01, and Tfirst’ = 1.35 ± 0.01 for the first return times of activity, again distinct from bulk exponents© 1996 The American Physical Society.
Branching processes and evolution at the ends of a food chain
TEBALDI, CLAUDIO;
1996
Abstract
In a critically self-organized model of punctuated equilibrium, boundaries determine peculiar scaling of the size distribution of evolutionary avalanches. This is derived by an inhomogeneous generalization of standard branching processes, extending previous mean field descriptions and yielding v = 1/2 together with T’ = 7/4, as distribution exponent of avalanches starting from species at the ends of a food chain. For the nearest neighbor chain one obtains numerically T’ = 1.25 ± 0.01, and Tfirst’ = 1.35 ± 0.01 for the first return times of activity, again distinct from bulk exponents© 1996 The American Physical Society.
File in questo prodotto:
Non ci sono file associati a questo prodotto.
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
