 A distinct pathway taken by appeals to group selection has focused on species and clade selection, particularly in work by paleobiologists and paleontologists (Grantham 1995; see also Doolittle 2017). Clades are monophyletic groups of organisms or species, groups defined by an ancestor and all and only its descendants. Steven Stanley and Stephen Jay Gould have been two of the most prominent defenders of the idea that there are large-scale patterns of evolutionary change that are due to species of clade selection, and both have done so in part by explicitly developing an extended analogy between individual organisms and species (e.g., Stanley 1979: 189; Gould 2002: 703–744). Amongst putative examples of clade selection are the evolution of planktotrophic mollusks in the late Cretaceous, being selected for greater geographic dispersal and so longevity (Jablonski 1986, 1987), the evolution of larger body size in males, selected via population density and geographic range (Brown &amp; Maurer 1987, 1989), and the evolution of flowering plants, selected via vector-mediated pollen dispersal (Stanley 1981: 90–91).