Answer:
They were originally classified based on visual characteristics that could be seen on the outside of the organism, however with the advancement of technology and science scientists realized that other characteristics (molecular, structural, etc.) should be considered.
Explanation:
If today nature has an order in the eyes of man, this is due to the work of the Swedish naturalist Carl Lineu, who in the 18th century, when comparing reproductive organs and structures of animals and plants, formulated the system of binomial classification of species. That is, if we can now call ourselves homo sapiens, such nomenclature of genus and species, respectively, is the result of Lineu's work. His contributions did not stop there, since in addition to the species' names, the naturalist grouped them into a hierarchical classification system. Thus, Kingdoms, Philos, Classes, Orders and their subcategories were born.
However, Lineu's classification system was originally established based on visual characteristics that could be seen on the outside of the organism, however with the advance of technology and science scientists realized that other characteristics (molecular, structural, etc.) should be considered.
