The two-empire system (two-superkingdom system) was the top-level biological classification system in general use before the establishment of the three-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 Radhey Gupta 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 |
This article uses material from the Wikipedia English article Two-empire system, which is released under the Creative Commons Attribution-ShareAlike 3.0 license ("CC BY-SA 3.0"); additional terms may apply (view authors). Content is available under CC BY-SA 4.0 unless otherwise noted. Images, videos and audio are available under their respective licenses.
®Wikipedia is a registered trademark of the Wiki Foundation, Inc. Wiki English (DUHOCTRUNGQUOC.VN) is an independent company and has no affiliation with Wiki Foundation.