How does Piggy enhance the theme of savagery and civilisation?

Piggy is distinguished only by his fat, asthma and myopia. Initially Ralph is a boy filled with wonder about being stranded on an island. Piggy has been conditioned to be a victim in the old world. He desperately seeks attention and reinforcement from those he finds are safe. Unfortunately Piggy's intelligence and physicality are taken as weakness by most of the other boys. Piggy taps into the boys' pack-like mentality to further isolate and exploit the weak of the group.