Taxonomic names reflect what we know about an organism's evolutionary relationships. The more closely related two species, the more taxa they share. Taxonomic designations are based on similarities between species, including visible characteristics, behavior, microscopic features, and sequences of genes and proteins.
Computers assist taxonomists by rapidly supplying information.
Field work and museums are still important parts of taxonomy. Taxonomy has changed as technology enabled biologists to discern more intricate details of cellular and molecular structure, anatomy and physiology, and behavior. Archaea are usually considered to be a part of Monera or a sixth kingdom. A system proposing three domains divides life into Archaea, Bacteria, and Eukarya. The domain system contradicts the five-kingdom system because it includes a separate grouping for the archaea.