Kingdom

The term kingdom is one of the seven major classification groups that biologists use to identify and categorize living things. These seven groups are hierarchical or range in order of size. The kingdom group is the first and largest group. The classification scheme for all living things is: kingdom, phylum, class, order, family, genus, and species.

As the broadest of all classification groups, kingdom is made up of phyla (singular, phylum). From the time of Greek philosopher and scientist Aristotle (384–322 b.c.) to the mid-twentieth century, only two kingdoms were recognized—Animalia (animal) and Plantae (plant). However, with increasingly modern and sophisticated techniques, biologists eventually came to recognize a five kingdom approach. These additional kingdoms were necessary in order to include other forms of life that did not belong in either the plant or animal kingdom. Today, the five kingdoms are monerans, protists, fungi, plants, and animals.

Monera, the smallest kingdom (with only about 4,000 species), includes the prokaryotic bacteria (single cells that do not have a nucleus) and certain types of algae. Bacteria play an important role as decomposers, and some monerans can make their own food through photosynthesis. Organisms in the kingdom Protista are eukaryotic (their cells contain a nucleus) but are both plantlike and animal-like. Some algae and protozoans are protists. The kingdom Fungi consists of molds, yeasts, and mushrooms. These are all multicelled organisms that live by absorbing food. Although these organisms look like plants, they do not make their own food. Members of the kingdom Plantae make their own food and often grow flowers and form seeds. The kingdom Animalia includes multicelled organisms that live by taking in food. Animalia is made up of vertebrates (animals with a backbone) and invertebrates (animals without a backbone). This is the largest kingdom, containing more than 2,000,000 species.

[See alsoClass; Classification; Family; Genus; Phylum; Species ]

king·dom / ˈkingdəm/ • n. 1. a country, state, or territory ruled by a king or queen: ∎  a realm associated with or regarded as being under the control of a particular person or thing: the kingdom of dreams. 2. the spiritual reign or authority of God. ∎  the rule of God or Christ in a future age. ∎  heaven as the abode of God and of the faithful after death. 3. each of the three traditional divisions (animal, vegetable, and mineral) in which natural objects have conventionally been classified. ∎  Biol. the highest category in taxonomic classification.

kingdom Topmost level (taxon) of the most widely adopted taxonomy for living organisms, the Five Kingdoms system. The Five Kingdoms are Animalia (animal), Plantae (plant), Fungi (fungus), Prokaryote, and Protoctist. Two subkingdoms are often recognized within Prokaryotae, Archaebacteria and Eubacteria, but the bacteria are so diverse that many taxonomists think they comprise more than one kingdom. Some believe that they merit the status of a new, even higher category, domains. See also eukaryote; plant classification

kingdom •jeroboam, Noam, Siloam •brougham •residuum, triduum •continuum • Brabham • album •sachem • Beecham • Mitchum •Adam, macadam, madam, Madame •avizandum, fandom, memorandum, nil desperandum, random, tandem •tarmacadam •shahdom, stardom, tsardom •beldam, seldom •addendum, corrigendum, referendum •heirdom • sheikhdom • Gaeldom •thanedom • saintdom •Edom, freedom, Needham •chiefdom, fiefdom •queendom • heathendom •crippledom • officialdom • Wyndham •Christendom • kingdom • princedom •wisdom • fogeydom • yuppiedom •rodham, Sodom •condom •boredom, whoredom •thraldom • Oldham • popedom •dukedom •Carborundum, corundum •poppadom • pauperdom • martyrdom •reductio ad absurdum • serfdom •earldom

kingdom In traditional classification systems, the highest category into which organisms are classified. The original two kingdoms, Plantae (see plant) and Animalia (see animal), have been supplemented by others, and most modern classification systems recognize five kingdoms: Bacteria (or Prokaryotae; see bacteria), Protoctista (including protozoa and algae), Fungi (see fungi), Plantae, and Animalia. However, the discovery of the archaebacteria (see Archaea) has led taxonomists to suggest a superordinate category in the taxonomic hierarchy – the domain.