Archaea

The Archaea are a group of single-celled microorganisms. A single individual or species from this domain is called an archaeon (sometimes spelled "archeon"). They have no cell nucleus or any other organelles within their cells. In the past they were viewed as an unusual group of bacteria and named archaebacteria but since the Archaea have an independent evolutionary history and show many differences in their biochemistry from other forms of life, they are now classified as a separate domain in the three-domain system. In this system, introduced by Carl Woese, the three main branches of evolutionary descent are the Archaea, Eukarya and Bacteria. Archaea are further divided into four recognized phyla, but many more phyla may exist. Of these groups the Crenarchaeota and the Euryarchaeota are most intensively studied.

Klappentext

The Archaea are a group of single-celledmicroorganisms. A single individual or species from this domain iscalled an archaeon (sometimes spelled "archeon"). They have nocell nucleus or any other organelles within their cells.In the past they were viewed as an unusual group of bacteriaand named archaebacteria but since the Archaea have an independent evolutionary history and show manydifferences in their biochemistry from other forms of life, they are now classified as a separate domain in the three-domain system. In this system, introduced by Carl Woese, thethree main branches of evolutionary descent are the Archaea, Eukarya and Bacteria. Archaea are further dividedinto four recognized phyla, but many more phyla may exist. Ofthese groups the Crenarchaeota and the Euryarchaeota are most intensively studied.