Taxonomic family
= Taxonomic family
A <taxonomic family> is a <taxonomic rank> above a <genus (biology)> and below a <taxonomic order>. A particular family is a named group of organisms placed at that rank; the rank itself is a position in the classification hierarchy.<Biology 2e by Mary Ann Clark and others>[section 20.1, Classification Levels and Figures 20.5–20.6]{ref}
For example, the cat family <Felidae> includes the genera <Felis> and <Panthera>. The family groups several genera, while each genus groups species. Scientific classifications draw on morphological, molecular and other evidence when deciding which organisms belong together.<Classification of living cat species by the IUCN SSC Cat Specialist Group>[Cat Classification Task Force account and evidence underlying the 2017 revision]{ref}
A constructed counting example separates hierarchy from abundance. If a hypothetical family contains two genera with three and five recognized species respectively, it contains eight species, provided those lists are disjoint and complete. It need not contain eight individual animals: the same eight species could be represented by millions of organisms.
The rank does not prescribe a fixed number of genera or species. Nor is a family label itself a measurement of evolutionary time. A <phylogenetic tree> represents hypotheses about ancestry and branching; ranked names organize those organisms at selected hierarchical levels. Changes in evidence can lead to revised membership without changing what the rank word means.<Biology 2e by Mary Ann Clark and others>[section 20.1, phylogenetic hypotheses and classification revisions]{ref}