Avida

The computer program avida is an auto-adaptive genetic system designed
primarily for use as a platform in Digital or Artificial Life research. The
avida system is based on concepts similar to those employed by the tierra
program developed by Tom Ray. It is a population of self-reproducing strings
with a Turing-complete genetic basis subjected to Poisson-random mutations.
The population adapts to the combination of an intrinsic fitness landscape
(self-reproduction) and an externally imposed (extrinsic) fitness function
provided by the researcher. By studying this system, one can examine
evolutionary adaptation, general traits of living systems (such as
self-organization), and other issues pertaining to theoretical or
evolutionary biology and dynamic systems.