How is Gene dynamic (how does he change from the beginning of the book to the end of the book)?

Gene's relationship with Finny changes frequently through
the story, as Gene analyzes and reacts to situations, comments, and actions he observes.
Gene considers himself and Finny to be best friends and comrades in all that is good and
positive (including stirring up trouble and finding ways to get out of punishment) when
the story starts.

As time goes by, Gene's feelings change
and he becomes jealous of the ease with which Finny accomplishes so many of the feats
that are important in a boys school. Gene is determined to become the top student to
place himself on equal footing with Finny, the unquestioned best athlete in the school,
and is even more threatened when he realizes Finny doesn't see any competition or threat
in Gene's academic accomplishment. Gene's impulsive reaction to this realization is to
retaliate by causing Finny to fall out of the tree. In the aftermath, Gene finally comes
to understand that there was only the competition that he imagined in his own mind,
"that wars were made...by something ignorant in the human
heart."