What caused scientists to divide the monera into the eubacteria and archaebacteria?

Kingdom Monera is divided into two groups, called Eubacteria and Archaebacteria. These two groups are both composed of tiny, ancient, single-celled organisms without organelles and generally with cell walls, but they differ greatly from each other in almost every other way. Scientists divided Archaebacteria and Eubacteria into these two groups mainly because of the environments they inhabit. Although Archaebacteriaâ??s name would suggest it is â??olderâ??, it is actually a younger group than Eubacteria, and very little is known about Archaebacteria because these species typically live in very hostile, extreme environments such as in acidic ocean thermal vents and miles below arctic ice sheets. Humans are much more familiar with Eubacteria, since we interact with these species every dayâ??most Eubacteria are completely harmless or beneficial, by way of fixing nitrogen for plant use in photosynthesis and other helpful functions. Archaebacteria differ from Eubacteria mainly in the chemical makeup of their cell walls, which scientists think hold the key to why Archaebacteria can live in such â??extremeâ?? conditions.