Wikipedia
Avida
Avida is an artificial life software platform to study the evolutionary biology of self-replicating and evolving computer programs ( digital organisms). Avida is under active development by Charles Ofria's Digital Evolution Lab at Michigan State University; the first version of Avida was designed in 1993 by Ofria, Chris Adami and C. Titus Brown at Caltech, and has been fully rengineered by Ofria on multiple occasions since then. The software was originally inspired by the Tierra system.