Ralph and Jack as a leader cause a majority of downhill for the boys. Ralph lost control over the group. Maybe Golding wishes to say that those who are different die first. Along with Ralph, there are a group of choir boys, a group of younger boys who they start to call "littluns", and an intelligent, civilized young boy named Piggy.
In Lord of the Flies, the shell signifies society and order. Jack used to do this with pigs, too. While Jack considers the boys inferior to himself, Ralph treats the boys as equals.
They soon learn of each other's existence when one of the older boys, Ralph, blows a conch shell and holds the first of many meetings. They would put the head on a spear and put it in the ground. But Jack and his group of hunters would not hunt for pigs, they would hunt for Jack.
Lord of the flies by William Golding is a great example of this