What were aristotle's contribution to modern classification

Aristotle have been contributed many things in our society:
He was able to create the system of classification in which it can group animals. by type.
It became the best system for over 2000 years.
He was able to do this because he record all the information that he was able to experience.
He divided the type of animals into 2 groups.
the with blood animals and the without blood animals

An informal structure in a bureaucracy would be something like so-called "office politics". where there's a formal structure set up for the organization, but then an informal subculture as well that has a way of organizing the bureaucracy further. this can be positive because it sets up an added degree of organization, albeit informal, within the bureaucracy.