The Mesozoic marine revolution

The modern oceans teem with animals which kill others to live, from killer whales that form pods of several individuals in co-ordinated attacks on their quarry (Pitman et al., 2001) to the drilling activities of tiny predatory foraminifers (Hallock et al., 1998). Most authors believe that predator-prey interactions, in tandem with competition, are key factorsS in controlling structure in modern communities. Classic work by Connell (1970) and Paine (1974) showed how predation in rocky shore communities prevented domination by major space occupiers and thus promoted overall diversity. In such situations taxa with antipredatory adaptations will be at an advantage and, if predation has been similarly important over geological time, we should anticipate that it has been an important agent of natural selection. Indeed, it is often suggested that the first appearance of shelled organisms in the “Cambrian explosion” might be due, in part, to the rise of predators (Conway Morris, 2001).