How to read a biological classification

A name is not the same thing as a taxon record. An organism may have common names, earlier scientific names and different treatments in different catalogues. Catalogue of Life also searches synonyms and connects them to the name accepted in that source. A search result under an old name does not necessarily represent a second species. Check the name status and the record to which it points.

Read a classification branch from broader groups towards narrower ones. Moving from a species to its genus lets you explore other included species; moving to the family lets you explore other genera. Names visible beside a selection may be only part of a longer list. Before treating a missing group as excluded by the source, check the filters, collapsed branches and loading state.

When comparing records, save the source and version as well as the name. Catalogue of Life makes dated releases available. The composition of groups and accepted names can change between releases. A saved version records which treatment underlies your comparison.

Try the route

Try it. Open *Arabidopsis thaliana*, locate its genus and family, then return to the species. Record the selected taxon, rank and classification version. Compare this path with one of the spruce records. Identify a shared displayed group, without assigning it an age or an evolutionary branch length: those require additional evidence.

Check your interpretation

Check your understanding. Does a synonym leading to the same accepted name give you another species? Compare the identity and status of the records before deciding. Does equal rank imply equal evolutionary age? Rank alone cannot establish that.

A classification diagram

A teaching diagram of classification levels. The selected source record supplies the actual names and group membership.

Teaching example: a species S belongs to genus G, which belongs to family F. The completed three-row note records S/species, G/genus and F/family. A synonym pointing to S changes the name used to find the record, not the number of accepted species in this example. The branch gives membership; it supplies no age for S, G or F.