Order

From Palaeos

Order

Linnaean hierarchy

In the Linnaean hierarchy (and taxonomic systems based on it), the Order is a taxonomic category between Class and Family. An order is group of organisms, e.g. Lepidoptera, Squamata, Primates, etc that although differing quite a bit among themselves still have a large degree of characteristics in common (e.g. all Lepidoptera (butterflies and moths) have minute scales on their wings, a soft-bodied herbivorous larval form (caterpillar), mouthparts in the adult specialized for feeding on nectar, etc). As with all the groupings whether a group of organisms ranks as an order or not is a subjective decision, although usually based on the traditional status of that group in earlier literature. There is also a tendency towards taxonomic inflation, especially among tetrapods but also certain groups of invertebrates, with sub- or infra-orders (and even families) being promoted to ordinal status. Also, invertebrate orders tend to differ among themselves much more than vertebrate orders (e.g. an invertebrate order e.g. Coleoptera (beetles) might correspond in diversity to a suborder or cohort or infraclass of Vertebrates). Cladism avoids this arbitrariness by doing away with the Linnean system altogether.

Some intermediate rankings:

Superorder

Grandorder

Order

Suborder

Infraorder

Parvorder