  We argue that the stochastic dynamics of interacting agents which replicate,
mutate and die constitutes a non-equilibrium physical process akin to aging in
complex materials. Specifically, our study uses extensive computer simulations
of the Tangled Nature Model (TNM) of biological evolution to show that
punctuated equilibria successively generated by the model's dynamics have
increasing entropy and are separated by increasing entropic barriers. We
further show that these states are organized in a hierarchy and that limiting
the values of possible interactions to a finite interval leads to stationary
fluctuations within a component of the latter. A coarse-grained description
based on the temporal statistics of quakes, the events leading from one
component of the hierarchy to the next, accounts for the logarithmic growth of
the population and the decaying rate of change of macroscopic variables.
Finally, we question the role of fitness in large scale evolution models and
speculate on the possible evolutionary role of rejuvenation and memory effects.
