The ability to peer into living things and inspect the evolutionary scorecard encoded in their genes has transformed the whole of biology, but few fields have had their core assumptions challenged as deeply as taxonomy. From the time of Carl Linnaeus, born 300 years ago this May, taxonomy has relied on the observation and comparison of physical forms. Now it is supplemented by access to what would once have been seen not as form, but as essence.
Linnaeus himself sought a universal classification of all creation, animal, vegetable and mineral. His categorizations were not uniformly valuable, but his systematic spirit, his stress on the concept of species, and the formal but adaptable conventions of nomenclature he introduced have endured. Nature is glad to celebrate his legacy in this special issue.
DNA sequencing is a gift that Linnaeus would surely have made great use of, but it brings its own problems. It is not always easily reconciled with the careful description, annotation and curation that have been the duty and delight of the taxonomists who carried the linnaean programme forward. The classical world in which Linnaeus worked may seem, at first glance, to contrast with our present age of change. Linnaeus believed in fixed species of knowable number created by God and observable by men, in a world more like the lawns and flowerbeds of a formal garden than Darwin’s dynamic “tangled bank”.