Biological classification bases have to keep on changing depending on our understanding of life forms.
The initial very basic methods of classification gradually have been replaced by more advanced and complex ideas. For example:
1. The two kingdom classification proposed by Aristotle based only on the habitat was replaced by three kingdom classification suggested by Haeckel.
2. Even the most accepted classification suggested by Whittaker which is the five kingdom classification was modified by whose based upon his understanding of bacteria dividing the Monera into archaebacteria and eubacteria.
