A review is presented of the various alternative conceptual definitions for biological species as well as of the contending theoretical explanations for the origin of species. This critical review elucidates a set of criteria that any adequate species concept must satisfy and a related set that must be satisfied by any adequate explanation of the speciation process. The result of this analysis is an argument that species are the natural products of biological processes and not artificial, human-…
Read moreA review is presented of the various alternative conceptual definitions for biological species as well as of the contending theoretical explanations for the origin of species. This critical review elucidates a set of criteria that any adequate species concept must satisfy and a related set that must be satisfied by any adequate explanation of the speciation process. The result of this analysis is an argument that species are the natural products of biological processes and not artificial, human-constructed classes. Species are historical "individuals" with unique evolutionary pasts. These "individuals" consist of lineages of organisms related to one another in an ancestor-descendent relationship, and originating from a single "event" such as the acquisition of some reproductive isolation mechanism or an hybridization event between two local populations. These "individuals" are cladistically monophyletic. The study of the processes by which species originate and are maintained is the study of the biological forces that either keep a particular lineage together as an historical entity with an unique evolutionary identity, and/or that cause such lineages to dissolve and lose that unique identity. ;In addition, it is argued that a satisfactory understanding of the pattern of organization seen in the natural world , and of the processes by which this pattern evolves cannot be obtained independently of one another. Descriptions of dynamic patterns of organization, and explanations of the processes involved in creating and maintaining those patterns must constantly inform one another if a correct account of either is to be had. In order to avoid circularity in such investigations, independent experiments must be performed to verify our understanding of the patterns we are attempting to explain as well as our understanding of the processes hypothesized as explanations for those patterns