Aristotle invented ancient taxonomy, which is the old way people used to classify plants and animals. Now we use the modern day classification system, which was influenced by Aristotle in many ways.
What Did Aristotle Invented?
I'm not sure if he really invented anything but he did develop a thing to classify plants and animals, especally sea creatures he wanted to identify, that is according to what I have read about him. He also founded most sciences that are here today, and some mathimatical terms.