The two-empire system (two-superkingdom system) was the top-level biological classification system in general use from the early 20th century until the establishment of the three-domain system (which itself is currently being challenged by the two-domain system). It classified cellular life into Prokaryota and Eukaryota as either "empires" or "superkingdoms". When the three-domain system was introduced, some biologists preferred the two-superkingdom system, claiming that the three-domain system overemphasized the division between Archaea and Bacteria. However, given the current state of knowledge and the rapid progress in biological scientific advancement, especially due to genetic analyses, that view has all but vanished.
Some prominent scientists, such as the late Thomas Cavalier-Smith, still hold and held to the two-empire system. The late Ernst Mayr, one of the 20th century's leading evolutionary biologists, wrote dismissively of the three-domain system, "I cannot see any merit at all in a three empire cladification." Additionally, the scientist argues for a return to the two-empire system, claiming that the primary division within prokaryotes should be among those surrounded by a single membrane (monoderm), including gram-positive bacteria and archaebacteria, and those with an inner and outer cell membrane (diderm), including gram-negative bacteria.
This system was preceded by Haeckel's three-kingdom system: Animalia, Plantae and Protista.
| Linnaeus 1735 | Haeckel 1866 | Chatton 1925 | Copeland 1938 | Whittaker 1969 | Woese et al. 1977 | Woese et al. 1990 | Cavalier-Smith 1993 | Cavalier-Smith 1998 | Ruggiero et al. 2015 |
|---|---|---|---|---|---|---|---|---|---|
| — | — | 2 empires | 2 empires | 2 empires | 2 empires | 3 domains | 3 superkingdoms | 2 empires | 2 superkingdoms |
| 2 kingdoms | 3 kingdoms | — | 4 kingdoms | 5 kingdoms | 6 kingdoms | — | 8 kingdoms | 6 kingdoms | 7 kingdoms |
| — | Protista | Prokaryota | Monera | Monera | Eubacteria | Bacteria | Eubacteria | Bacteria | Bacteria |
| Archaebacteria | Archaea | Archaebacteria | Archaea | ||||||
| Eukaryota | Protista | Protista | Protista | Eucarya | Archezoa | Protozoa | Protozoa | ||
| Protozoa | |||||||||
| Chromista | Chromista | Chromista | |||||||
| Vegetabilia | Plantae | Plantae | Plantae | Plantae | Plantae | Plantae | Plantae | ||
| Fungi | Fungi | Fungi | Fungi | Fungi | |||||
| Animalia | Animalia | Animalia | Animalia | Animalia | Animalia | Animalia | Animalia |
See also
References
- Cavalier-Smith, T (2002). "The neomuran origin of archaebacteria, the negibacterial root of the universal tree and bacterial megaclassification". International Journal of Systematic and Evolutionary Microbiology. 52 (1): 7–76. doi:10.1099/00207713-52-1-7. PMID 11837318.
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- Haeckel, E. (1866). Generelle Morphologie der Organismen. Reimer, Berlin.
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- Chatton, É. (1937). Titres et Travaux Scientifiques (1906–1937). E. Sottano, Sète, France.
- Copeland, H.F. (1938). "The kingdoms of organisms". Quarterly Review of Biology. 13 (4): 383–420. doi:10.1086/394568. S2CID 84634277.
- Copeland, H.F. (1956). The Classification of Lower Organisms. Palo Alto: Pacific Books. p. 6. doi:10.5962/bhl.title.4474.
- Whittaker, R.H. (January 1969). "New concepts of kingdoms of organisms". Science. 163 (3863): 150–160. Bibcode:1969Sci...163..150W. doi:10.1126/science.163.3863.150. PMID 5762760.
- Woese, C.R.; Balch, W.E.; Magrum, L.J.; Fox, G.E.; Wolfe, R.S. (August 1977). "An ancient divergence among the bacteria". Journal of Molecular Evolution. 9 (4): 305–311. Bibcode:1977JMolE...9..305B. doi:10.1007/BF01796092. PMID 408502. S2CID 27788891.
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- Woese, C.; Kandler, O.; Wheelis, M. (1990). "Towards a natural system of organisms: proposal for the domains Archaea, Bacteria, and Eucarya". Proceedings of the National Academy of Sciences of the United States of America. 87 (12): 4576–4579. Bibcode:1990PNAS...87.4576W. doi:10.1073/pnas.87.12.4576. PMC 54159. PMID 2112744.
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- Cavalier-Smith, T. (1992). "Origins of secondary metabolism". Ciba Foundation Symposium. Novartis Foundation Symposia. 171: 64–80, discussion 80–7. doi:10.1002/9780470514344.ch5. ISBN 9780470514344. PMID 1302186.
- Cavalier-Smith, T. (1993). "Kingdom protozoa and its 18 phyla". Microbiological Reviews. 57 (4): 953–994. doi:10.1128/mmbr.57.4.953-994.1993. PMC 372943. PMID 8302218.
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- Ruggiero, Michael A.; Gordon, Dennis P.; Orrell, Thomas M.; Bailly, Nicolas; Bourgoin, Thierry; Brusca, Richard C.; Cavalier-Smith, Thomas; Guiry, Michael D.; Kirk, Paul M.; Thuesen, Erik V. (2015). "A higher level classification of all living organisms". PLOS ONE. 10 (4): e0119248. Bibcode:2015PLoSO..1019248R. doi:10.1371/journal.pone.0119248. PMC 4418965. PMID 25923521.
The two empire system two superkingdom system was the top level biological classification system in general use from the early 20th century until the establishment of the three domain system which itself is currently being challenged by the two domain system It classified cellular life into Prokaryota and Eukaryota as either empires or superkingdoms When the three domain system was introduced some biologists preferred the two superkingdom system claiming that the three domain system overemphasized the division between Archaea and Bacteria However given the current state of knowledge and the rapid progress in biological scientific advancement especially due to genetic analyses that view has all but vanished Phylogenetic and symbiogenetic tree of living organisms showing the origins of eukaryotes and prokaryotes Some prominent scientists such as the late Thomas Cavalier Smith still hold and held to the two empire system The late Ernst Mayr one of the 20th century s leading evolutionary biologists wrote dismissively of the three domain system I cannot see any merit at all in a three empire cladification Additionally the scientist argues for a return to the two empire system claiming that the primary division within prokaryotes should be among those surrounded by a single membrane monoderm including gram positive bacteria and archaebacteria and those with an inner and outer cell membrane diderm including gram negative bacteria This system was preceded by Haeckel s three kingdom system Animalia Plantae and Protista Linnaeus 1735 Haeckel 1866 Chatton 1925 Copeland 1938 Whittaker 1969 Woese et al 1977 Woese et al 1990 Cavalier Smith 1993 Cavalier Smith 1998 Ruggiero et al 2015 2 empires 2 empires 2 empires 2 empires 3 domains 3 superkingdoms 2 empires 2 superkingdoms2 kingdoms 3 kingdoms 4 kingdoms 5 kingdoms 6 kingdoms 8 kingdoms 6 kingdoms 7 kingdoms Protista Prokaryota Monera Monera Eubacteria Bacteria Eubacteria Bacteria BacteriaArchaebacteria Archaea Archaebacteria ArchaeaEukaryota Protista Protista Protista Eucarya Archezoa Protozoa ProtozoaProtozoaChromista Chromista ChromistaVegetabilia Plantae Plantae Plantae Plantae Plantae Plantae PlantaeFungi Fungi Fungi Fungi FungiAnimalia Animalia Animalia Animalia Animalia Animalia Animalia AnimaliaSee alsoDomain biology Kingdom biology Three domain systemReferencesCavalier Smith T 2002 The neomuran origin of archaebacteria the negibacterial root of the universal tree and bacterial megaclassification International Journal of Systematic and Evolutionary Microbiology 52 1 7 76 doi 10 1099 00207713 52 1 7 PMID 11837318 Mayr E 1998 Two empires or three Proceedings of the National Academy of Sciences 95 17 9720 9723 Bibcode 1998PNAS 95 9720M doi 10 1073 pnas 95 17 9720 PMC 33883 PMID 9707542 Gupta Radhey S 1998 Life s Third Domain Archaea An Established Fact or an Endangered Paradigm Theoretical Population Biology 54 2 91 104 doi 10 1006 tpbi 1998 1376 PMID 9733652 Linnaeus C 1735 Systemae Naturae sive regna tria naturae systematics proposita per classes ordines genera amp species Haeckel E 1866 Generelle Morphologie der Organismen Reimer Berlin Chatton E 1925 Pansporella perplexa Reflexions sur la biologie et la phylogenie des protozoaires Annales des Sciences Naturelles Zoologie et Biologie Animale 10 VIII 5 84 Chatton E 1937 Titres et Travaux Scientifiques 1906 1937 E Sottano Sete France Copeland H F 1938 The kingdoms of organisms Quarterly Review of Biology 13 4 383 420 doi 10 1086 394568 S2CID 84634277 Copeland H F 1956 The Classification of Lower Organisms Palo Alto Pacific Books p 6 doi 10 5962 bhl title 4474 Whittaker R H January 1969 New concepts of kingdoms of organisms Science 163 3863 150 160 Bibcode 1969Sci 163 150W doi 10 1126 science 163 3863 150 PMID 5762760 Woese C R Balch W E Magrum L J Fox G E Wolfe R S August 1977 An ancient divergence among the bacteria Journal of Molecular Evolution 9 4 305 311 Bibcode 1977JMolE 9 305B doi 10 1007 BF01796092 PMID 408502 S2CID 27788891 Woese C R Fox G E November 1977 Phylogenetic structure of the prokaryotic domain the primary kingdoms Proceedings of the National Academy of Sciences of the United States of America 74 11 5088 5090 Bibcode 1977PNAS 74 5088W doi 10 1073 pnas 74 11 5088 PMC 432104 PMID 270744 Woese C Kandler O Wheelis M 1990 Towards a natural system of organisms proposal for the domains Archaea Bacteria and Eucarya Proceedings of the National Academy of Sciences of the United States of America 87 12 4576 4579 Bibcode 1990PNAS 87 4576W doi 10 1073 pnas 87 12 4576 PMC 54159 PMID 2112744 Cavalier Smith T 1981 Eukaryote kingdoms Seven or nine Bio Systems 14 3 4 461 481 doi 10 1016 0303 2647 81 90050 2 PMID 7337818 Cavalier Smith T 1992 Origins of secondary metabolism Ciba Foundation Symposium Novartis Foundation Symposia 171 64 80 discussion 80 7 doi 10 1002 9780470514344 ch5 ISBN 9780470514344 PMID 1302186 Cavalier Smith T 1993 Kingdom protozoa and its 18 phyla Microbiological Reviews 57 4 953 994 doi 10 1128 mmbr 57 4 953 994 1993 PMC 372943 PMID 8302218 Cavalier Smith T 1998 A revised six kingdom system of life Biological Reviews 73 3 203 266 doi 10 1111 j 1469 185X 1998 tb00030 x PMID 9809012 S2CID 6557779 Cavalier Smith T 2004 Only six kingdoms of life PDF Proceedings of the Royal Society B Biological Sciences 271 1545 1251 1262 doi 10 1098 rspb 2004 2705 PMC 1691724 PMID 15306349 Retrieved 2010 04 29 Cavalier Smith T June 2010 Kingdoms Protozoa and Chromista and the eozoan root of the eukaryotic tree Biol Lett 6 3 342 345 doi 10 1098 rsbl 2009 0948 PMC 2880060 PMID 20031978 Ruggiero Michael A Gordon Dennis P Orrell Thomas M Bailly Nicolas Bourgoin Thierry Brusca Richard C Cavalier Smith Thomas Guiry Michael D Kirk Paul M Thuesen Erik V 2015 A higher level classification of all living organisms PLOS ONE 10 4 e0119248 Bibcode 2015PLoSO 1019248R doi 10 1371 journal pone 0119248 PMC 4418965 PMID 25923521
