Family (biology)

In biological classification, family (Latin: "familia", plural "familiae") is a taxonomic rank. Exact details of formal nomenclature depend on the Nomenclature Code which applies.:"Example": "Walnuts and Hickories belong to the Walnut family" is a brief way of saying: the Walnuts (genus "Juglans") and the Hickories (genus "Carya") belong to the Walnut family (family Juglandaceae). The classifications of taxonomy are life, domain, kingdom (biology), phylum, class (biology), order (biology), family (biology) genus, and species

History of the concept

Family, as a rank intermediate between order and genus, is a relatively recent invention.

The term "familial" was coined by French botanist Pierre Magnol in his "Prodromus historiae generalis plantarum, in quo familiae plantarum per tabulas disponuntur" (1689) where he called families ("familiae") the seventy-six groups of plants he recognised in his tables. The concept of rank at that time was still "in statu nascendi," and in the preface to the "Prodromus" Magnol spoke of uniting his families into larger "genera," which is far from how the term is used today.

Since the beginning of the 20th century, however, the term has been consistently used in its modern sense. Its usage and characteristic ending of the names belonging to this category are defined in the "Codes" of botanical and zoological nomenclature.

Almost all families are named for a type genus, and are formed by adding the ending "-idae" (animals) or "-aceae" (plants) to the stem of the genus name. Exceptions are:
*Caprifoliaceae, Aquifoliaceae, and Fabaceae, named for their type species "Lonicera caprifolium", "Ilex aquifolia", and "Vicia faba".
*Theaceae, named for "Thea", a synonym of "Camellia".
*Eight families of plants with alternate names. Fabaceae is also called Leguminosae, Poaceae Gramineae, etc.
*Elapidae. The type genus is "Homoroselaps", which was originally named "Elaps" but was temporarily moved to a different family and the name changed as a result.

ee also

* Systematics - the study of the diversity of life
* Cladistics - the classification of organisms by their order of branching in an evolutionary tree
* List of families - list of family names in the taxonomy of biology
* Phylogenetics - the study of evolutionary relatedness among various groups of organisms
* Taxonomy
* "Compare" Family
* Virus classification
*protein family
*gene family