Our word, mimic, is rooted in the ancient Greek term mimesis, which has also entered the English language. From Wikipedia: Mimesis, the imitation of life or nature in the techniques and subject matter of art and literature
Aristotle demonstrated that mimesis is the characteristic that distinguishes art from craft--the fine arts from all other productive technologies. Mimesis is the skill the artist employs to produce a work of art, the representation of specific slices of reality--slices chosen and carefully selected by the artist. Aristotle develops this view of mimesis throughout the Poetics, and in typical fashion explores just about every aspect of its use in producing art.
Plato was probably the first to lead Aristotle down the path of esthetics--the study of art. As was often the case, Aristotle grasped the theme that his teacher introduced and explored it more thoroughly and beyond the scope of anything dreamt of by anyone at the Academy, many times in direct opposition to Platonic philosophy.
This is the general view--that Aristotle learned much of what he was to later develop from Plato and the philosophical talk at the Academy, a view that I accept only to a certain degree. There's little evidence that this was always the case, and in his study of art as well as biology there are other factors that probably influenced Aristotle. He was the son of the physician and--according to tradition--friend to King Amyntus of Macedon (Father to Philip, grandfather to Alexander the Great). Aristotle certainly had read and listened to performances of Homer and others long before leaving the North. From early childhood, Aristotle may have spent time at the Macedonian court in Pella, and it's known that Euripides was welcomed there generations before. With this connection and the possibility of a library of Euripidean works--and maybe some esthetic studies going on at Pella--one can at least speculate that Aristotle learned quite a bit about Greek drama prior to going to Athens.