Using the Schulze model for Monte Carlo simulations of language competition, we include a barrier between the top half and the bottom half of the lattice. We check under which conditions two different languages evolve as dominating in the two halves.

Ecology and evolution are inseparable. Motivated by some recent experiments, we have developed models of evolutionary ecology from the perspective of dynamic networks. In these models, in addition to the intra-node dynamics, which corresponds to an individual-based population dynamics of...

Monte Carlo simulations of a Sznajd model show that if a near-consensus is formed out of four initially equally widespread opinions, the one which at intermediate times is second in the number of adherents usually loses out against the third-placed opinion.

We here present a fixed agents version of an original model of the emergence of hierarchies among social agents first introduced by Bonabeau et al. Having interactions occurring on a social network rather than among “walkers” does not drastically alter the dynamics. But it makes social...

Very recently we developed a dynamic network model for eco-systems that achieved “unification” of “micro” and “macro”-evolution. We now propose an extension of our model so as to stabilize the eco-system and describe speciation in a more realistic manner.

Ising spins put onto a Barabási–Albert scale-free network show an effective phase transition from ferromagnetism to paramagnetism upon heating, with an effective critical temperature increasing as the logarithm of the system size. Starting with all spins up and upon equilibration pinning the...

After a brief review of our recent works on “unified” models of evolutionary ecology, we have generalized our “unified” model by taking into account spatial variations from one “patch” to another. We model the spatial extension of the ecosystem (i.e., the geography) by a square...

Using Monte Carlo simulations, we study the evolution of contingent cooperation and ethnocentrism in the one-shot game. Interactions and reproduction among computational agents are simulated on undirected and directed Barabási–Albert (BA) networks. We first replicate the Hammond–Axelrod...

We propose a generic model of eco-systems, with a hierarchical food web structure. In our computer simulations, we let the eco-system evolve continuously for so long that we can monitor extinctions as well as speciations over geological time scales. Speciation leads not only to horizontal...