Book Description
In the first chapter, we argue that an individual organism ought not to be defined in terms of genetic homogeneity, but rather by the evolutionary criteria of the alignment of fitness interests, the export of fitness due to interdependence for survival and reproduction, and adaptive functional organization. We consider how these concepts apply to various putative individual organisms, review the costs and benefits of intraorganismal genetic heterogeneity, and demonstrate that high relatedness is neither necessary nor sufficient for individuality. In the second chapter, we model the benefits and costs of genetic mosaicism for a long-lived tree in coevolution with a short-lived pest. We demonstrate benefits of mosaicism for trees at both the individual and population levels when somatic mutation introduces new defenses. In the third chapter, we develop a game theoretic model of the decision to reject or fuse with a potential partner in a colonial ascidian, based on weighing costs and benefits of fusion. We find that once fused, the interactions between cell lineages are cooperative in the soma, but competitive in the germline.
