GPW wants to thank the following persons for many discussions on the subject of the paper and some for reading an earlier versions of this paper: Martin Baatz, Homayoun Bagheri, Maria Blanco, Reinhard Bürger, Leo Buss, Walter Fontana, Jim Crutchfield, Terry Jones, Junhyong Kim, Stuart Kauffman, Manfred Laubichler, Bernhard Misof, Christian P‡zm‡ndi, Peter Stadler, Andreas Wagner. LA is grateful to the Hawaii Institute of Geophysics and Planetology, the Maui High Performance Computing Center, and the Santa Fe Institute for facility support, and thanks Dan McShea, Brian Goodwin, and Stuart Kauffman for insightful discussions on the manuscript. The financial support by NSF grant BIR 9400642 and the Yale Institute of Biospheric Studies to GPW is gratefully acknowledged. This is contribution #27 of the Center of Computational Ecology.