When Ralph blew into the conch the first time, the boys gathered. There was no order to gather; they just did it seemingly automatically. The conch, like the overriding voice of a teacher or a parent, had a commanding presence that the boys responded to. They were accustomed to such authority. Once the boys gather for the first time, it isn't long before Ralph is elected to be the leader primarily because he is the one holding the shell and the one who blew into it causing the boys to gather. Even as Ralph suggests that they ought to have a leader, he raises the shell that is still in his hands. The shell gave Ralph the same commanding presence that the shell itself had. In the second chapter, at their next gathering, Ralph again is holding the conch shell. He says that the boys need rules and one of the rules will be that whoever is holding the conch shell may speak. Thus the shell is given the power to determine who speaks at the gatherings. As the story progresses and the society of the boys falls apart bit by bit, the shell becomes less and less of a symbol of authority and power and civilization. By the time Piggy is killed in chapter 11, the shell has lost all its power and the civilization is gone from the island as well.