Ralph begins as a rather naive boy. When they first land on the island, he cares about no one but himself. Power changes him, but not in negative ways.
He is elected leader only because he blows the conch, Which Piggy pointed out could be done. However, once leader, he takes the responsibility seriously. He institutes rules and order, trying to get the boys to build shelters, keep a fire going, and take turns speaking.
"[I]f we have a signal going, they'll come and take us off. And another thing. we ought to have more rules. Where the conch is, that's a meeting. The same up here as down here" (42).
Ralph also has to contend with threats to his power from Jack. This causes him to grow up fast. Jack is a harsher, more savage version of himself. He is a natural leader with a built-in base because of the hunters. Later, he will tear the tribe apart with his appealingly savage ways.
When the tribe breaks, Ralph tries to bring it back together. Unfortunately, he never had solid leadership skills even if he did develop some compassion. He tries to convince Jack that he is still in charge, when Jack and the hunters give them meat. It proves disastrous.
When Piggy is killed and Ralph runs, he sees an adult for the first time. He cries, knowing what they have become. He knows he could not prevent it.
The changes Ralph undergoes, from self-centered to group-centered, do not reflect the island as a whole. He is never able to convince the other boys to be responsible. They are all too happy to abandon the trappings of society. If they had had a stronger leader (not Ralph the incompetent or Jack the savage), they might not have had a schism, a forest fire, or two murders.