Bedau, Mark A., Emile Snyder, C. Titus Brown, and Norman H. Packard. “A comparison of evolutionary activity in artificial evolving systems and in the biosphere.” In Proceedings of the fourth European Conference on Artificial life , pp. 125-134. Cambridge, MA: MIT Press, 1997.
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Bedau and Packard [7] devised an approach to quantifying the adaptive phenomena in articial systems. We use this approach to dene two statistics: cumulative evolutionary activity and mean cumulative evolutionary activity. Then we measure the dynamics of cumulative evolutionary activity, mean cumulative evolutionary activity and diversity, on an evolutionary time scale, in two articial systems and in the biosphere as re-acted in the fossil record. We also measure these statistics in selectively-neutral analogues of the articial models. Comparing these data prompts us to draw three conclusions: (i) evolutionary activity statistics do measure continual adaptive success, (ii) evolutionary activity statistics can be compared in articial systems and in the biosphere, and (iii) there is an arrow of increasing cumulative evolutionary activity in the biosphere but not in the articial models of evolution. The third conclusion is quantitative evidence that the articial evolving systems are qualitatively dierent from the biosphere.