The Nonavian Reptiles : Origins and Evolution

摘要: Early in the history of systematic biology, scientists were interested in documenting the wonders of “the creation.” Specimens procured on expeditions were placed in collections, and spectacular hand-colored plates graced giant monographs, showpieces of discovery and exploration. Darwin’s work shifted interests to natural selection and the process of speciation. In addition to Darwin’s volumes on evolution, whose main tenets were predicated on observations of island speciation patterns, Alfred Wallace’s (1880) Island Life explained the great diversity of species on islands. Today, in an expanded concept islands remains the central focus for investigations of speciation and the mechanisms that drive change. Islands come in the form of Petri dish cultures of bacteria, bottles of Drosophila, mesic sky islands (mountaintop habitats isolated by intervening desert), and subaerial landmasses (surrounded by water). Evolution has remained the unifying principle of biology, and the concepts and methods associated with it have made their way into virtually all aspects of human culture. Several groups of islands have been instructional in the development of evolutionary theory. The Galapagos Islands clearly had the greatest impact. However, the islands in the Sea of Cortés have also significantly influenced our understanding of the speciation process. Within herpetology, studies have looked at the evolution of insular gigantism (Case 1978b; Petren and Case 1997), anatomical and genetic variability (Soulé et al. 1973), and species composition (Case 1975, 1983; Murphy 1983a). Others have addressed island biogeography in the manner of MacArthur and Wilson’s (1963, 1967) model of colonization and extinction (Case 1975, 1983; Wilcox 1978, 1980) versus historical constraints imposed by plate tectonics (Murphy 1983). Various ecological attributes of insular populations have been compared to those of the founding source (reviewed in Case 1983). Controversies over peninsular effects have been evaluated (Taylor and Regal 1978, 1980; Seib 1980; Murphy 1991), as have the phylogenetic relationships of taxa (reviewed below). These are but a few examples of the herpetological investigations. The intensity of study in the Sea of Cortés has not waned in recent years. To the contrary, it has intensified. Renewed interest in the evolution of the Baja California herpetofauna owes much to the nature of the peninsula and its associated islands.