<P> The term "domain" was proposed by Woese et al. (1990) in his three - domain system . This term represents a synonym for the category of dominion (Lat . dominium), introduced by Moore in 1974 . However, only Stefan Luketa uses the term "dominion". He placed Prion and Virus under two "dominions" separately . </P> <P> Each of these three domains contains unique rRNA . This forms the basis of the three - domain system . While the presence of a nuclear membrane differentiates the Eukarya from the Archaea and Bacteria, both of which lack a nuclear membrane, distinct biochemical and RNA markers differentiate the Archaea and Bacteria from each other . </P> <P> Archaea are prokaryotic cells, typically characterized by membrane lipids that are branched hydrocarbon chains attached to glycerol by ether linkages . The presence of these ether linkages in Archaea adds to their ability to withstand extreme temperatures and highly acidic conditions, but many archea live in mild environments . Halophiles, organisms that thrive in highly salty environments, and hyperthermophiles, organisms that thrive in extremely hot environments, are examples of Archaea . Archaea evolved many cell sizes, but all are relatively small . Their size ranges from 0.1 μm to 15 μm diameter and up to 200 μm long . They are about the size of bacteria or similar to the size of a mitochondrion in a eukaryotic cell . Members of the genus Thermoplasma are the smallest of the archaea . </P> <P> Even though bacteria are prokaryotic cells just like Archaea, their membranes are made of unbranched fatty acid chains attached to glycerol by ester linkages . Cyanobacteria and mycoplasmas are two examples of bacteria . They characteristically do not have ether linkages like Archaea, and they are grouped into a different category--and hence a different domain . There is a great deal of diversity in this domain, and between that and horizontal gene transfer, it is next to impossible to determine how many species of bacteria exist on the planet . </P>

Make a chart on major domains of the earth