One-Dimensional Systematist: Perils in a Time of Steady Progress

This commentary offers a critical assessment of the molecular age of biological systematics and deals with certain basic tendencies that seem to indicate a new phase of the discipline. These tendencies have engen dered a prevalent one-dimensional thought that un dermines the very foundation of systematics. This new phase has produced an advanced state of conformity with its consequent stifling of criticism, restricting the legitimization of problems and methods, research pri orities, and last but not least, job opportunities and modes of organization of institutions. Biological systematics is a multidimensional scien tific discipline that describes, names, classifies, and de termines relationships among the Earth's biota. It ac complishes these deeply interdependent tasks through surveys, inventories, collections, description of species, phylogenetic reconstruction, hierarchical classifica tions, monographing, and application of rules of no menclature. All these activities, except phylogenetic re construction, are encompassed by the sub-discipline named taxonomy (Wilson 2003). Systematics provides a reference system for the whole of biology and therefore can be seen as both the most basic and the most wide-ranging area of biology. It is the most basic because organisms cannot be dis cussed or treated in a scientific way until some clas sification has been achieved to recognize them and give them names. It is the most wide-ranging because it gathers together and summarizes everything that is known about the characteristics of organisms, whether geographical, morphological, physiological, genetic, ecological, or molecular. Beneath the fundamental scientific importance of systematics for biology, lies a growing urgency. The roughly 1.7 million species known to science to date probably represent at best fewer than 15% of the actual number. Of the named species, it is estimated that less than 1% have been studied beyond the essentials of geographic location, habitat preference, and diagnostic morphology. At the same time, thousands of species (known and unknown) are threatened by imminent ex tinction (Raven 2002). Were we required to characterize the current age of systematics by any single epithet, we should be tempt ed to call it "the molecular age. " Molecular data have provided a new class of features that allow not only phybgenetic reconstruction of closely related taxa, but also broad scale comparisons across all organisms from bacteria to mammals and plants. Unquestionably, we are witnessing an extraordinary time when molec ular systematics is generating an unprecedented rev olution within the discipline (Daly et al. 2001). Despite the tremendous advances, there are pro found perils in the molecular age of systematics: 1. An unbalanced emphasis favoring phylogenetic recon struction based on molecular data at the expense of taxonomy; 2. A narrow research program that ignores many aspects of organismal biology and fragments systematics; 3. An unbalanced education of the new generation of systematists; 4. A depreciation of natural science collections as part of a broader trend away from organismal biology; 5. A slowdown of taxonomic work that will affect the conservation of biodiversity; and 6. An intellectual climate that marginalizes those with different views. I will briefly elaborate on these perils and their consequences. An Unbalanced Emphasis. Taxonomy was once the proud flagship of the natural sciences. Charles Darwin, the founder of the theory of natural selection, working in Cirripedia (barnacles) in the 19th century and Willi Hennig, the founder of modern phylogenetic recon struction, working in Diptera (flies) in the 20th century, were both practicing taxonomists. However, in the last 30 years taxonomy has seen a gradual loss of credibil ity among fellow scientists. This image problem is based on misconceptions of how taxonomy works. The view that taxonomy is a purely descriptive branch of knowledge that consists only of observations (Anony mous 2004) is a clear example of these misconceptions. In fact, taxonomy is a scientific discipline that requires description, but also theoretical, empirical and episte mological rigor, a hypothesis-driven approach, and field and lab expertise (Stuessy 1990; Carvalho et al. 2005). Furthermore, classification systems are hypotheses. A taxon, the basic unit of taxonomy, is a classification system and as such is a scientific hypothesis about or der in nature (Thiele and Yeates 2002). Like every sci entific hypothesis, a taxon goes beyond the evidence (observations) for which it purports to account. That is, a taxon has greater scientific content (e.g., predictive capability and explanatory power) than the empirical 217