Santa Fe Institute. July 21, 2005 3:04p.m. Ch12-Martinez-rev page 287 Network Evolution: Exploring the Change and Adaptation of Complex Ecological Systems Over Deep Time Neo D. Martinez 1 INTRODUCTION One of the most exciting new directions in research on food webs and ecological networks is network evolution or, in other words, the development of the struc- ture and function of ecological networks over time scales long enough for node selection and speciation to occur (Caldarelli et al. 1998; Drossel and McKane 2002; Worden 2003; Yoshida 2003; Cattin et al. 2004; Rossberg 2004; Anderson and Jensen 2005). Most food-web studies focus on shorter-term snapshots of network structure and time series of network dynamics. The difference between long-term evolution over “deep time” and short-term structure and dynamics is a familiar one. Hutchinson distinguished the two by suggesting that we “view the natural world as the ecological theater, serving as a stage for the evolutionary play” (Hutchinson 1965). Following this suggestion, research on network evolu- tion goes well beyond contemporary topology, theatrical population booms and busts, and more staid equilibria. That is, network evolution encompasses a broad Ecological Networks: Linking Structure to Dynamics in Food Webs, edited by Mercedes Pascual and Jennifer A. Dunne, Oxford University Press. 287