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|Linnaean Hierarchy||Local Cladogram|
Life `--LUCA |--Eubacteria `--Neomura |--Archaea `--Eukarya
(see Archaea phylogeny for more)
The Archaea (also called Archaebacteria) are a group of prokaryotes that became something of a cause celebre when rDNA analysis by Carl Woese and colleagues discovered a large genetic distance between them and the other prokaryotes. This lead to their promotion as a 'third domain' of life, in addition to the Eubacteria and eukaryotes (Woese, Kandler & Wheelis, 1990). In a number of features, they are more similar to eukaryotes than Eubacteria, as well as having an assortment of unique features of their own.
The name "Archaea" should not be confused with the geologic time period Archean (also spelt Archaean). However Archaea most likely evolved 3.6 Bya during the Archean, and with Eubacteria were the only form of life at that time, which may or may not add to the confusion.
The fact that Archaea seem to be closer to Eukarya than to Eubacteria, means it is not unlikely that the group is paraphyletic, with ancestral "urkaryotes" and/or eukaryotes evolving from archaean ancestors.
For more on Archaea, see the following pages:
|Fossil record | Phylogeny | Characteristics | Ecology | Links | References|
Credits CKT060920, modified MAK060628