Why are the classification systems changing every now and then?

Explanation

All early systems of classification of organisms were artificial, i.e., based on few superficial similarities. As the advancement in technologies occurs the system of classification also starts changing. Classification system development has been started at about the time of Aristotle. During the 18th centuary new system of classification was laid down, i.e., Natural System of classification. Further advancement in technologies leads to formulation of still more advanced systems of classification. Due to the recent branches of taxonomy i.e., cytotaxonomy, chemotaxonomy, numerical taxonomy (phenetics), experimental taxonomy, karyotaxonomy etc., new system of classification comes into existance. So the system of classification is changing every now and then.