When Carl Woese first published his three-domain system, it was believed that the domains Bacteria, Archaea, and Eukaryota were equally old and equally related on the tree of life.
Cando Carl Woese publicou o seu sistema de tres dominios, críase que os dominios Bacteria, Archaea, e Eukarya eran igual de antigos e estaban relacionados dun modo igual na árbore da vida.