Kingdom is the highest rank, after the domain, which is normally used in the biological taxonomy of all organisms. Each kingdom is split into phyla.
There are 5 to 7 kingdoms in taxonomy. Every living thing comes under one of these kingdoms and some symbionts, such as lichen, come under two. There are at least:
Linnaeus 1735[1] |
Haeckel 1866[2] |
Chatton 1925[3][4] |
Copeland 1938[5][6] |
Whittaker 1969[7] |
Woese et al. 1977[8][9] |
Woese et al. 1990[10] |
Cavalier-Smith 1993[11][12][13] |
Cavalier-Smith 1998[14][15][16] |
---|---|---|---|---|---|---|---|---|
2 kingdoms | 3 kingdoms | 2 empires | 4 kingdoms | 5 kingdoms | 6 kingdoms | 3 domains | 8 kingdoms | 6 kingdoms |
(not treated) | Protista | Prokaryota | Monera | Monera | Eubacteria | Bacteria | Eubacteria | Bacteria |
Archaebacteria | Archaea | Archaebacteria | ||||||
Eukaryota | Protoctista | Protista | Protista | Eucarya | Archezoa | Protozoa | ||
Protozoa | ||||||||
Chromista | Chromista | |||||||
Vegetabilia | Plantae | Plantae | Plantae | Plantae | Plantae | Plantae | ||
Fungi | Fungi | Fungi | Fungi | |||||
Animalia | Animalia | Animalia | Animalia | Animalia | Animalia | Animalia |
The kingdom-level classification of life is still widely employed as a useful way of grouping organisms. Sometimes entries in the table, which are next to each other, do not match perfectly. For example, Haeckel placed the red algae (Haeckel's Florideae; modern Rhodophyta) and blue-green algae (Haeckel's Archephyta; modern Cyanobacteria) in his Plantae, but in modern classifications they are considered protists and bacteria respectively. However, despite these differences, the table gives a useful summary.