Family (biology)

In biological classification, family () is a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the prefix sub-: subfamily (Latin: ). a taxonomic unit, a taxon, in that rank. In that case the plural is families (Latin ) ::Example: Walnuts and hickories belong to the Juglandaceae, or walnut family.

What does and does not belong to each family is determined by a taxonomist. Similarly for the question if a particular family should be recognized at all. Often there is no exact agreement, with different taxonomists each taking a different position. There are no hard rules that a taxonomist needs to follow in describing or recognizing a family. Some taxa are accepted almost universally, while others are recognised only rarely.

History of the concept

Carolus Linnaeus used the word in his (1751) to denote major groups of plants: trees, herbs, ferns, palms, and so on. He used this term only in the morphological section of the book, discussing the vegetative and generative organs of plants. Subsequently, in French botanical publications, from Michel Adanson's (1763) and until the end of the 19th century, the word was used as a French equivalent of the Latin (or ). In nineteenth century works such as the of Augustin Pyramus de Candolle and the of George Bentham and Joseph Dalton Hooker this word was used for what now is given the rank of family.

In zoology, the family as a rank intermediate between order and genus was introduced by Pierre André Latreille in his (1796). He used families (some of them not named) in some but not in all his orders of "insects" (which then included all arthropods).

Uses

See also

References

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