How does Ralph change throughout Lord of the Flies?

At the start of the story, Ralph is optimistic, calm, and confident.  He seems to know what needs to be done to get rescued and he knows that leadership is required.  Since he does immediately state the obvious need for leadership, he is a natural choice to the boys to be the leader.  He lacks the ability to lead however.  He does not continue to command respect from the boys, he does not see that things get done and get done correctly; instead, he complains to the boys that they aren't doing things right.  Unfortunately, he does little more than complain.  By chapter 9, Ralph is beginning to sink into savagery like the other boys.  He actively participates in the circle of chanting and dancing boys who kill Simon, even if he doesn't actually lift a spear and stab at Simon himself.  He realizes later, the horror of what happened.  That attests to the idea that he still has some civility left in him.  By the last chapter, however, he is slinking through the brush and trees on the island, trying to think like a wild pig as he attempts to elude the boys who are hunting him in order to kill him.  He has had to become savage in order to survive.  At the end, when the boys are discovered by the naval officer, Ralph has just enough civilization left in him to cry for all the civilization he has lost.