The fossil record of life has been shown to provide evidence for scaling laws in both time series and in some statistical features. This evidence was suggested to be linked with a self-organized critical phenomenon by several authors. In this paper we review some of these models and their...

Complex, fractal structures are widespread in ecological systems and in some characteristic features of evolutionary processes. The origin of such patterns in terms of their dynamics is a challenging problem. A theory for these phenomena might have important implications in issues like the...

Recent studies on the fossil record time series has shown that there is consistent evidence for self-similarity i.e., long-range correlations with power-law behavior. The existence of such fractal structures means that, when looking at a given time frame, some basic properties remain the same if...

Recent experiments involving competition of clonal populations of RNA viruses have shown that competition among virus strains of approximately equal relative fitness can result in the eventual competitive exclusion of one of the species. As competition proceeds in time, both the winers and the...

Rainforests are legendary because of their extreme species richness. In the richest rain forests every second tree on a hectare is a different species. As a consequence, most species are rare. Using field data from studies in different parts of the world, we show that species-rich plots often...

In this paper we introduce a new approach to optimization problems based on a previous theoretical work on extinction patterns in macroevolution. We name them Macroevolutionary Algorithms (MA). Unlike population-level evolution, which is employed in standard genetic algorithms, evolution at the...

Urban centers present all over the world striking similarities which translate into universal laws describing their growth and morphology. In this paper, we study a simple 2-dimensional cellular automata model containing what we identfiy as essential ingredients in the dimographic change. the...

In recent studies, new measures of complexity for nonlinear systems have been proposed based on probabilistic grounds, as the LMC measure (Phys. Lett. A 209 (1995) 321). All these measures share an intuitive consideration: complexity seems to emerge in nature close to instability points, as for...

Some authors have hypothesized that the observed self-synchronized activity in ant colonies provides some adaptive advantages, and, in particular, it has been suggested that task realization may benefit from this ordered temporal pattern of behavior (Robinson, 1992; Hatcher et al., 1992). In this...

The dynamics of extinction and diversification of life is not a simple stochastic process, driven by random inputs. Biotic interactions are known to play a very important role in the population response to physical factors. In spite of this fact, it is not clear how the ecological scale is...