Archaea

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Archaea

Evolutionary biology
One of the three domains of living organisms: Archaea, Bacteria and Eukaryota. While Archaea are single-celled, they are unlike bacteria given their independent evolutionary history. Archaea differ from Eukaryota in their ribosomal structure and the presence—in some—of introns in the genome, as well as other features (e.g., different membrane composition).
 
Molecular biology
Archaea are of interest in biotechnology as they have unique biochemical features (e.g., enzymes of theromophiles, such as Taq polymerase, the “workhorse” enzyme of PCR) and are extremely stable at high temperatures. Archaea include metabolic oddities (e.g., extreme halophiles, which live in extremely salty environments), methanogens (which produce methane) and sulphur-dependant extreme thermophiles (which can live in extremely hot environments).

Archaea phyla
• Crenarchaeota
• Euryarchaeota
• Korarchaeota
• Nanoarchaeota
• Thaumarchaeota (recently proposed)

Archaea

( formerly
References in periodicals archive ?
Convective flow is characteristic of low-viscosity, phenocrysts-poor, magmas like those parental to Archaean megacrystic and layered intrusive anorthosite.
At last, the editors of Science magazine held a press conference in August 1996 to declare the new archaean domain.
Recent -- Red Lateritic soil and Black Clayey / Sandy soil Tertiary -- Laterites as caps Upper Cretaceous to Eocene -- Deccan traps with intertrappean beds UNCONFORMITY Archaean -- Granites and Gneisses
1991; Petersell & Levchenkov 1994) suggested that the South Estonian granulites were more likely early Proterozoic than Archaean in age.
13]C [greater than or equal to] -60%o), is found in late Archaean and early Proterozoic kerogens, 2.
1999) postulated that the geology of the wheatbelt could be resolved into 4 hydrogeologically significant themes: major faults, minor faults, mafic dykes, and Tertiary sediments, set against the background of a fifth, the Archaean granite and granitic gneiss country rock, which affect the development of dryland salinity through [K.
The different types of bacterial interactions in the Ciso pool give rise to an anaerobic microbial ecosystem, a reminder of what aquatic ecosystems must have been like in the Archaean Age (between 3,800 and 2,500 million years ago), when the earth's atmosphere contained no free oxygen and the only organisms were prokaryotic bacteria.
Darwinistic thought holds that life began spontaneously sometime during the Archaean period and that organic evolutionary changes are due to contingent mutations, the survival of which is determined by natural selection.
This is the first time the entire gene set of an archaean organism has been deciphered.
1978) The evolution of Archaean greenstone terrains, Eastern Goldfields Province, Western Australia.
A wide range of geological environments are encountered in the country, with nearly half of the country covered by younger sedimentary successions, which cover extensive Precambrian terrains, some of which is Archaean in age.
This area is historically referred to as the Kilo-Moto region, a semi-continuous Archaean Kabalian greenstone belt hosting a number of active gold projects.