Why does Ralph call an assembly? How do the boys react?Is the bond of friendship between ralph and jack is disappearing? Why?

Ralph calls an assembly to set things straight.  While
Jack and the hunters have been victorious in killing their first pig, Ralph and Piggy
have suffered a major disappointment when a ship passed by, and there was no signal
fire.  Ralph, probably for the first time, realizes how much he wanted to be rescued.
 So, we have two groups emerging:  Jack's group that wants to hunt and have fun,
thinking only of the here and now; and Ralph's group that is concerned with shelters and
rescue.

Ralph's meeting is an attempt to establish rules
and procedures for survival and rescue. And Ralph cares very much about this meeting. He
plans out what he is going to say beforehand.  He even knows how he will make his
announcements.  In other words, Ralph assumes a true leadership role, acting as a leader
who is very much concerned about the welfare of the group.  Jack, of course, resents
Ralph's authority.  He does not care for Ralph's rule, and wants only to do what he
wants when he wants.  He still is interested in having fun on the island.  As Ralph
begins to respect Piggy's input more because he and Ralph have the same goals, Ralph
moves further away from Jack.

The boys listen to Ralph
initially.  But the meeting breaks up when Ralph allows them to discuss the beastie.  It
is the boys' fear that Ralph cannot control or allay.  Instead of quelling the boys'
fears, the discussion of the beastie only heightens them.  Jack's power on the island is
increased as the fear of the unknown increases.