Systematics and diversity (original) (raw)

Systematics and Diversity This chapter provides a short introduction to systematics: the branch of biological science responsible for recognising, comparing, classifying and naming the millions of different sorts of organisms that exist. As such, systematics provides the basic framework for the whole of biology, and is the fundamental discipline of biodiversity. The work can be divided into a number of activities, including classification, identification and nomenclature. These are often grouped as taxonomy, broadly defined as the classification and naming of organisms. This chapter gives the background for Chapter 3, which discusses some key theoretical and practical problems arising from the concept of the species. BIOLOGICAL CLASSIFICATION The ultimate task of systematics is to document and understand the extent and significance of biological diversity. Within this framework, taxonomy performs four basic functions: differentiation (recognition of taxa), identification (universal diagnosis of taxa), symbolisation (application of universal names), and comparison (relative relationships of taxa). Vernacular or folk taxonomies provide limited local systems for the first three but have little to tell us about the last. Individuals and characters are the most basic units of biological classification. On the basis of features held in common (attributes or characters), individuals can be grouped together into a large number of different classes. These classes are of two kinds (often regarded as sharply distinct, although in reality they form a continuum). On the one hand, individual organisms can be divided into such groups as freshwater, marine, terrestrial, planktonic, nocturnal, pollinators, etc. Alternatively, they can be placed into taxonomic categories of species, genera, families,