DarwinTunes started with randomly generated sounds from a computer and then allows short loops to be chosen by anyone who participates. This 'hive mind,' internet-based method of musical selection has proven to mirror organic evolutionary processes. From the abstract of their PNAS paper:
Music evolves as composers, performers, and consumers favor some musical variants over others. To investigate the role of consumer selection, we constructed a Darwinian music engine consisting of a population of short audio loops that sexually reproduce and mutate. This population evolved for 2,513 generations under the selective influence of 6,931 consumers who rated the loops’ aesthetic qualities. We found that the loops quickly evolved into music attributable, in part, to the evolution of aesthetically pleasing chords and rhythms.
Here is a short explanation with examples of the process unfolding interspersed:
It's really pretty cool. I went to the game and played for a bit, creating some 'children.' Here are my three favorites I parented:
And of course I had to make a short mix of all three:
Check it out.