Class (biology)
The class (English class, Latin classis) is a special hierarchical level of the hierarchical taxonomy according to Linné. In it, the class is one rank above the order (ordo) and below the phylum (phylum or division). In some cases, several classes are combined to form a superclass. A class can also be divided into subclasses. This is equally true in virology, where the prescribed name endings are -viricetes for classes and -viricetidae for subclasses. Furthermore, sometimes in zoology the term infraclass (lat. infra "underneath") or subclass is additionally used when a taxon between subclass and superclass is necessary; between the superclass and the class the series is still placed if necessary.
Other rank designations in class rank have been proposed, but are not in general use; their use has remained limited to isolated cases. James Farris of the American Museum of Natural History, for example, proposed a system by which arbitrary rank designations for intermediate ranks could be generated by standardized prefixes such as mega-, sub-, infra-, and combinations thereof. The intermediate ranks legion and cohort (between subclass and order) proposed by Malcolm McKenna have also been applied only sporadically.
In the meantime, phylogenetic systematics, or cladistics, has joined classical, rank-based systematics in biological systematics. Today, cladistic methods are the standard of the corresponding disciplines. For systematics, different scientists draw different consequences from this. According to the more radical view, the classification according to Linnaean system is obsolete and should no longer be used. On the one hand, this is due to the fact that Linné classified organisms according to their similarity and not according to their relationship, so that non-monophyletic units can result; however, these are now generally considered to be no longer justified. Taxa designated as classes according to classical systematics, even if monophyletic, also do not necessarily have equal rank among themselves. Thus, they may have different evolutionary ages and comprise different numbers of subtaxa such as species. According to the moderate view, the classical ranks can still be used if these constraints are respected. Thus, the use of the rank class, like the other ranks, says nothing about what taxonomic method the using scientist has used.
The four traditionally distinguished classes of the terrestrial vertebrate series are the amphibians, reptiles, mammals and birds. To the tribe of arthropods is assigned the class of insects.
