Living things are organized into more general groups, each of which shares some particular group of characteristics.
This can then be used to develop taxonomic schemes for the classification of organisms.
In 1970, Robert Whittaker developed a five-kingdom system of classification based on ecology, evolution and structure.
In 1980, Carl Woese proposed a new system based on
ribosomal RNA (rRNA) analysis of many different types of cells. Living
things could be classified in three superkingdoms or Domains:
Archea, Eubacteria and Eukarya based on each group's specific rRNA and
other biochemical differences.