Russ, You say: "I'm trying a slightly different tack with Tierra, of artificially inducing mass extinctions every now and then. I have also tried reducing parsimony pressure from time to time (I'm not sure what would be the biological world equivalent of this - possibly variation in background radioactivity or cosmic rays)..."
If your 'organisms' in Tierra were organized around feedback loops that developed by exploring their environments, might you experiment with have them be variably exploratory? Phil > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On > Behalf Of Russell Standish > Sent: Friday, October 10, 2008 1:16 AM > To: [EMAIL PROTECTED]; The Friday Morning Applied Complexity > Coffee Group > Subject: Re: [FRIAM] Relaxed Selection, a b-level posting > > One should not confuse economics with biological selection. It would > seem plausible that good economic times might lead to rapid evolution > of economies, such as during the recent Internet bubble for instance, > but not that it would have any influence on us at the genetic level. > > The sort of idea that David Green was proposing was that ecosystems > (aka foodwebs) would cycle between a chaotic and a stable phase. My > take on this is that immediately after a mass extinction, just about > any foodweb is stable, because there are not enough connections to > make it chaotic. Selection under such circumstances would be fairly > relaxed. As evolution proceeds, the foodweb becomes more > complex until such a time as chaotic behaviour sets in. Extinction > becomes increasingly likely, and corresponding selection becomes > "fierce". > > Cycles of mass extinction followed by species radiation _may_ be a > driving cause of ecosystem complexity. > > I'm trying a slightly different tack with Tierra, of artificially > inducing mass extinctions every now and then. I have also tried > reducing parsimony pressure from time to time (I'm not sure what would > be the biological world equivalent of this - possibly variation in > background radioactivity or cosmic rays). But currently my simulation > code is broken, so I haven't got too far with this to date :( > > Cheers > ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org
