Just when I think I've gained some sophiostication of understanding on something and wrapped my head around at least some of the work that has gone on, I read an old thread like this and find myself awed by the depth of thought that has proceeded me on this project. It is truly phenominal.
I'm no biologist and this is probably half baked, but here's a point of view on the subject. One reason organisms may have evolved limited lifespans, even at the single cell level, may have been becuase it was advantageous to do so. Namely, in a changing environment, the biggest mistake for a genotype to make would be not to change, not to create variation and thus anticipatory adaptability to environmental changes at the species level. Not dying is not changing. Imperfect reproduction is the mechanism that has evolved for creating variation - Darwin called it "Descent with Modification" - thus successful organisms are by definition, ones who have offspring. Now, in any system, in any ecosystem, there is limited energy. The earth is not a closed system - energy comes in, energy leaves - but the sum of that energy is finite. It is bounded. There is an upper limit and thus organisms cannot have offspring at infinitum. Only so much sunlight falls on the pond. Energy must made made available to the next generation somehow - the next generation must get a chance to get their share, to get their turn or that's the end of that brach of the tree. Having offspring that don't get access to energy, that don't survive to reproduce is the same as not having offspring at all which is the same as not changing. Now, since there is phyiscal proximity between parent and offspring, at least for single cell asexually reproducing species, one way to free up energy for your offspring, once you have had enough offspring to have taken a number of steps in different directions in the fitness landscape from where you stand, is to die. Maybe one of those steps was an incremental improvement over yourself, a small step up mount improbable. Seems plausable to me.
So, I think what we may be missing is not a mechanism for simulating this evolved trait, but rather more programatic ways to provide a changing environment over time so as to encourage anticipatroy varaition and perhaps the evolution of such adaptaions as limited lifespans. A changing environment favors the prepared genome.
I've actually been thinking a little about this in a related way in that I've been thinking about ways to limit overpopulation through evironmental changes: perhaps having a set of configurable overpopulation rules that increase the nrg/cycle cost or decrease the number or energy of veggies once the population hits a high water mark (and vice versa). It's a raw idea needing more thought, but I do think that a (gradually) changing environment is key to providing selective pressures which favor variation. And at the risk of sounding like a broken record on the subject, this won't work very well IMHO until the primary mutation probability is encoded in the genome and is itself subject to selection so that the tendency towards greater or lesser variation in different areas of the genome can be selected for....
-E