Artificial systems are ways of grouping organisms by similar features, but not in a way that necessarily reflects evolutionary, or phylogenetic, relationships. Artificial systems are useful for identifying organisms, but they may obscure important evolutionary relationships. We are in a period of profound change in our understanding of taxonomic relationships because of important advances in biology, notably cladistics , molecular biology and paleobotany . These developments are causing a reevaluation of every level of the taxonomic heirarchy, and allowing scientists to develop phylogenetic classifications. Far from being a stuffy, arcane discipline, taxonomy is an exciting science at the frontiers of biology.
Phylogenetic relationships are difficult to analyze.
Living tree species may closely resemble one another even if they are not closely related. Many tree species hybridize easily. Any phylogenetic scheme for the classification of trees is subject to change as we learn more about molecular relationships and the fossil record. For most purposes, the family, genus and species level are the most useful. Higher taxa , especially orders, are subject to considerable change as we learn more.