Taxonomy is the study of scientific classification, in particular the classification of living organisms according to their natural relationships. Taxonomy's first father was the philosopher Aristotle (384-322 BC), sometimes called the "father of science." It was Aristotle who first introduced the two key concepts of taxonomy as we practice it today: classification of oranisms by type and binomial definition.
Early classification systems probably grouped organisms as to whether they were beneficial or harmful. Another ancient classification system recognized 5 animal groups - domestic animals, wild animals, creeping animals, flying animals, and sea animals.