Coevolution
Coevolution, the reciprocal evolutionary change of ecologically interacting species, is a central process shaping the structure of biological communities and affects almost all organisms on earth. Its power as an evolutionary force arises from the often intense selection imposed by interactions between species, and from the fact that other species themselves evolve, thereby necessitating continual and sometimes rapid evolutionary change. The pattern and process of coevolution can be observed both at the microevolutionary (e.g., evolution of traits among populations) and macroevolutionary scales (e.g., generation of new species). From a microevolutionary perspective, coevolution can give rise to rapid evolutionary dynamics that may affect ecological processes; moreover, coevolution leads to the evolution of adaptations (and counter-adaptations) in interacting species and thereby may give rise to coadaptation of traits between species. Coevolution can drive divergent microevolutionary trajectories both within and between populations potentially leading to diversification and ultimately speciation. Thus, coevolution is a process linking microevolution and macroevolution. From a macroevolutionary perspective, tightly coevolving species may cospeciate such that the phylogenies of interacting clades appear congruent. This bibliography begins with a historical perspective, before considering conceptual issues surrounding coevolution and the debates that have shaped the field. The key publications exploring the pattern and process of coevolution at both microevolutionary and macroevolutionary scales are outlined.