A COMPUTER SIMULATED EXAMPLE OF EXTINCTION WITH
A TYPICAL POWER LAW SIGNATURE:

Ecologist Tom Ray suggested that co-evolving systems create ecosystems which attain the poised edge of chaos. Ray began studying model ecosystems in which the organisms are self-reproducing computer programs that live and spawnwithin the confined world of a computer's memory core.

He named his artificial simulated world, Tierra. Each program was capable of copying it's self onto an adajent lcation in the core.The programs are also able to mutate, thus forming a community with
one another. Many lively things occurred in the computerized ecosystem. Organisms emerged acting as parasites, borrowing the instructions of their hosts to replicate themselves and hosts respond by forming boundaries to ward off the parasites.

In time however, Ray's organisms expired. A plot of the size distribution of extinction events in Tierra was performed to look for a typical power law signature, indicative of complex systems.

Complexity index