Ralph plays a dominant role that is inevitably crucial to the development of the plot.
He is the first among the boys to emerge from the creepers. When he finds the conch and is taught how to use it by Piggy, he blows it and its sound attracts and draws the other boys to where he and Piggy are. There and then he beings to exercise some form of authority over the boys by assuring that it is only he who has the conch that has permission to speak.
Next he initiates the democratic process of electing the leader and is thus elected when he squarely beats Jack in the leadership contest. As a practical expression of his leadership, he leads the delegation that explores the island and reveals that they are probably the only inhabitants on the island.
As a leader who takes action, he beings to work out the strategy for their survival on the island and their eventual rescue in eranest. This he does by wisely relying on Piggy's exceptional intelligence. And so he assures the other boys that his father, a naval officer, will come to the rescue as soon as possible, ... "he's commander of the navy. When he gets leave, he'll come and rescue us", he says. In this regard, he suggests that they make a fire that will raise somke to attract rescuers.
In spite of Jack's antagonism to his leadership!, Ralph remains cool-headed and does all he can to run an inclusive administration by conceding the choir boys' leadership to Jack so that he can come on board. Rather than use brute force like Jack, he pursues the peaceful option and places the unity of all the boys over and above all other considerations.
As a caring leader, he courageously defends Piggy as much as he can against the unwarranted brutality of Jack. He grieves deeply when Simon's life is abruptly cut short and painfully mourns when Piggy's life is untimely terminated. As a good leader, he never wavers even when he is virtually deserted by all the boys. And when he is constrained to fight for dear life, he does so bravely and tenaciously thwarts the sinister attempts put together by Jack to kill him. As the hero in the novel, Ralph's fighting spirit eventually pays off. As the author's embodiment of civilization and acceptable leadership, he lives on while Jack, the antagonist, is consumed by the uncontrollable inferno he wickedly raises. He is thus able to respond proudly and loudly, "I am" to the rescuing naval officer's question: "Who's the boss here?"