Taxonomies

Taxonomy is the science of naming, describing, and classifying organisms. It also refers to the broader practice of organizing information into classifications or categories. In biology, taxonomy seeks to arrange living things into a hierarchical framework that reflects evolutionary relationships. The standard Linnaean system assigns ranks such as domain, kingdom, phylum, class, order, family, genus, and species, and uses binomial nomenclature (for example, Homo sapiens) to provide unique names for species. Modern taxonomy is closely linked with systematics, the study of evolutionary relationships, and many taxonomic groups have been revised to reflect phylogenetic knowledge, with clades replacing or supplementing traditional ranks.

Biology faces challenges: the species concept varies; cryptic species may be difficult to distinguish; polyphyletic groups require redefinition; and names, synonyms, and homonyms can complicate communication. Molecular data have reshaped classifications, sometimes contradicting morphology-based groupings, leading to ongoing revisions.

In information science, taxonomy describes a structured scheme for organizing concepts, terms, or content. It supports information retrieval, data integration, and metadata tagging. Taxonomies are commonly hierarchical, but may also be polyhierarchical or facet-based. They are distinct from ontologies, though related, and from thesauri used for synonym mapping. Construction methods include top-down expert design, bottom-up term collection, or hybrid approaches, and may combine manual curation with automated text mining.

Taxonomies underpin biodiversity inventories, conservation planning, libraries, and digital knowledge management. Widely used taxonomic resources include the Catalogue of Life, ITIS, and specialized genome and biodiversity databases, as well as organizational taxonomies in content management systems.