... ofspecies we see on an island, and how does thisnumber depend on the size and isolation of theisland? Gilbert White’s question of populationabundance was revisited and expanded beyondthe sterile ... (Nowak and May, 1992; Herz, 1994; Killingback and Doebeli, 1996; Mitteldorf and Wilson, 2000; Hauertet al., 2002; Le Galliard et al., 2003; Hauert and Doebeli, 2004; Szabo´ and Vukov, 2004) and ... (Nowak and Sigmund, 1998a).In a world of binary moral judgements (Nowak and Sigmund, 1998b; Leimar and Hammerstein,HOW POPULATIONS COHERE 112001; Fishman, 2003; Panchanathan and Boyd,2003; Brandt...