Models for the evolution of life try to clarify the long term dynamics of an evolving system of species. A recent model accounts for species' interactions with various degrees of symmetry, connectivity, and species abundance. This is an improvement on previous, simpler models, which apply random fitness levels to species. The findings demonstrate that the resulting replicator ecosystems do not appear to be a self-organized critical model, unlike the so-called Bak Sneppen model.

Source: Refined biological evolution model proposed