Jem is a character who's evolution is more obvious than Scout's. He often plays with Scout at the beginning. As he grows up, he starts an interest in football and puts all his energy in it. Jem kind of grows up like his father, Atticus the lawyer. You can the see the resemblance of their thoughts. Scout says she can kind of talk to Jem like she can talk to Atticus.

Over the course of the book, he becomes a man. It is noticable in his behavior. He grows up in a way more wanted by society.