Answer:
Ralph stands for civilization and democracy. This is the main way he contributes to the theme.
The general theme of 'Lord of the Flies' is the tension between the human impulse towards savagery and the rules of civilization which are designed to contain and minimize it. Ralph uses his authority to establish rules, protect the good in people, and to enforce the moral and ethical codes of the English society the boys were raised in. He defines half of the storyline. Ralph does not have the power hungry attitude Jack does.