Chapter 22 Archaea

Abstract

For years, all prokaryotes were classified under one kingdom: Monera. By the late 1970s, scientists were starting to recognize that this classification system grossly simplified prokaryotic origins. It soon became clear that certain species of prokaryotes known as archaebacteria had characteristics that made them very distinct from common bacteria or eubacteria. These organisms seemed to inhabit extreme environments and contained unique cell membranes and walls that were not found in any other organisms. Additionally, 16S rRNA analysis clearly indicated that archaebacteria did not share a monophyletic common ancestor with other bacteria and that archaebacteria and eubacteria diverged before the evolution of eukaryotic cell [1].