Lord Of The Flies Chapters 2&3

At the beginning of chapter two the boys were starting to get more organized especially with the conch shell, and then the idea of the fire. Towards the end of the chapter the order turns into chaos with the fire and the boys are getting very disorganized and frustrated. I don't understand what the word "beastie" means. I'm not sure if the little boy was talking about an animal or maybe like a tree or something that he saw the shadow of. Also in chapter 3 it was kind of a given that Jack and Ralph are going to have arguments here and there because they are against each other. Ralph wanted to build the huts for the little boys, but Jack didn't want to help because he wanted to go catch some meat. I'm wondering what is going to happen to their civilization?