 The lungfish and the coelacanth appear key to understanding the origins of the tetrapods, which has remained a major question in the reconstruction of evolutionary history since Darwin. But this is just one example among many. Bowler (1996) surveys the development of phylogenetics over this time period and examines a number of these debates in more detail such as whether the arthropods form a monophyletic group, and the question of the origin of birds, and, in particular, how they are related to the extinct dinosaurs.