The class ( English class , Latin classis ) is a hierarchical level of the hierarchical taxonomy according to Linnaeus . In it, the class is one rank above the order ( order or ordo ) and below the phylum ( stem or division ). In some cases, several classes are combined into a superclass. A class can also be divided into subclasses. This also applies in virology , the prescribed name endings are -viricetes for classes and -viricetidae for subclasses. In addition, sometimes in zoology addition, the term Infra class ( lat. Infra "including") or subclass used when a taxon between subclass and superordination is necessary; If necessary, the series is placed between the superclass and the class .
In the meantime, in the biological systematics, the phylogenetic systematics, or cladistics , have appeared alongside the classic, rank-based systematics . Cladistic methods are now the standard in the relevant disciplines. Different scientists draw different consequences for the system. According to the more radical view, the classification according to the Linnaeus system is out of date and should no longer be used. On the one hand, this is due to the fact that Linnaeus classified organisms according to their similarity and not according to their relationship, so that monophyletic units can not result; Today, however, these are generally no longer justified. According to the classical system, taxa designated as classes , even if they are monophyletic, but also do not necessarily have the same rank among each other. So they can have a different evolutionary age and include different numbers of sub-taxa such as species. According to the moderate view, the classic ranks can still be used if these restrictions are observed. The use of the rank level class, like the other ranks, does not say anything about which taxonomic method the scientist used.