A taxonomic kingdom is a major taxonomic rank conventionally below a domain and above a taxonomic phylum. A kingdom is a particular taxon at that rank, while the rank word identifies its place in a classification. In a familiar classification of eukaryotes, animals and plants belong to different kingdoms within the same domain.[ref]
Nested membership permits several descriptions of one organism. An individual animal can belong to the eukaryotic domain, the animal kingdom and a particular phylum simultaneously. The levels select different scales of grouping, rather than offering competing identifications.
A constructed classification database illustrates the information supplied by parent relationships. Suppose kingdom A contains phyla P and Q, with 8 and 12 recorded species, while kingdom B contains phylum R with 20 recorded species. Both kingdom totals are twenty, but A's records are divided between two phyla and B's are not. A query grouped only by kingdom loses that distribution. The counts describe the stipulated records, not a census of complete biological diversity.
The kingdom rank does not prescribe a fixed number of phyla or a particular evolutionary age. Nor does sharing that rank establish equal evolutionary distance between any two groups. A phylogenetic tree represents hypotheses about ancestry and branching; a ranked classification assigns names to selected groupings.[ref] Keeping the rank, the membership and the supporting evidence separate makes comparisons across classifications more interpretable.
Articles by others on the same topic
There are currently no matching articles.