 These processes all involve restrictions on the ability of the lower-level entities to function as interactors and replicators, and the emergence of upper-level collectives as both interactors and replicators. The degree to which lower-level entities are thus restricted can vary. For example, somatic cells are still capable of bearing individual fitness, of outcompeting neighboring cells, and of producing more progeny. Thus, they are not yet “post-populational”; they “retain crucial Darwinian features in their own right” (Godfrey-Smith 2009: 126). However, they are dependent on the germ-line cells for the propagation of new collectives, and thus their ability to act as replicators is necessarily curtailed. Thus, in order to prevent subversion and encourage cooperation, such a transition requires both the “generation of benefit” and the “alignment of reproductive interests” (Godfrey-Smith 2009: 124, with terminology from Calcott 2008; see Booth’s 2014 analysis of heterokaryotic Fungi using Godfrey-Smith’s approach). For example, in the case of multicellularity, the latter can be accomplished by “close kinship within the collective” (Godfrey-Smith 2009: 124).