Tensions reach a high point in chapter 7 when it becomes clear that Jack is challenging Ralph's leadership. Jack is starting to do whatever he wants.

From the beginning, Jack has resented that Ralph was elected leader. Ralph is naturally good-looking, athletic, sensible, caring, and charismatic, making him the natural choice, but Jack has a will to power, and as head of the choir boys, he wants to be put in charge. A clash has been inevitable and now is coming to a head.

Ralph realizes for the first time how much Jack hates him. Jack asserts his own authority by saying that he is going to go up the mountain to look for the beast:

“I’m going up the mountain.” The words came from Jack viciously, as though they were a curse.

Ralph realizes that it is foolish to make such a trek, but when Jack sneers at him with the word "Coming?" Ralph knows he has to go along to maintain power.

Ralph is highly frustrated with Jack's behavior. Ralph, a good leader, behaves rationally and looks out for the interests of all the boys. He is willing and able to defer present pleasure for later rewards. Jack, on the other hand, has grown impatient with this form of leadership. He wants power at all costs and doesn't care who gets hurt or what gets destroyed as long as he gets it.

Tensions between Ralph and Jack have been bubbling along for most of the previous six chapters. But in chapter 7, they come to a boil, with Jack openly showing his hostility towards Ralph and his authority.

Jack thinks that he should be in charge, and so for him, it's nothing short of humiliating to have to take orders from Ralph, especially when they're out hunting on the mountain, which Jack regards as his specialty. To that end, he insists on leading the group to the top of the mountain. As well as usurping Ralph's authority, this will make Ralph look weak in front of the other boys. Under the circumstances, Ralph has no choice but to continue on to the top of the mountain; otherwise, he will lose face.

Ralph wants to know why Jack hates him. But the reason behind Jack's animosity really isn't all that hard to spot: Ralph's the leader, a position Jack thinks is rightfully his. Jack's hatred is borne of resentment. And so he takes every possible opportunity to undermine Ralph's leadership, so that when the time comes, he'll be able to step into the breach and exercise absolute power over the other boys on the island.

Animosity between Jack and Ralph is evident in chapter 7 as the boys are hunting for the beast. Ralph is clearly tired of Jack's lack of civility and antagonistic nature, while Jack has lost all respect for Ralph as their leader. As night falls on the island, Ralph suggests that the boys stop searching for the beast and resume in the morning. He also suggests...