How has the environment of the island changed Piggy's character in Lord of the Flies?

I don't think that Piggy's character does change over the course of the book. I think that Piggy is a constant against whom the changes in the other charcaters can he more easily viewed. Piggy's appearance, other than one lens of his spectacles getting broken, doesn't alter much either. He is mentioned as being the only boy on the island whose hair doesn't appear to grow. He talks like an adult from the start and does exactly the same immediately before his death, when he delivers his speech to Jack's tibe on the causeway. Piggy is set in his ways and reluctant to alter his views about anything