1. It is method of biological classification based on the similarities and differences in structure of certain chemical compounds present among the organisms being classified.
2. Thus, it is a classification based on chemical constituents of organisms.
3. For e.g. Cell wall with peptidoglycan is present in Bacteria while it is absent in Archaea.
Among Eukarya, fungi have chitinous cell wall, while plants have cellulosic cell wall.