At the start of this chapter in 1990, there were 12 original members in the Alpha pledge class. The family trees below shows their descendants. The people who are marked in red color do not have any little brothers, thus leaving that part of the tree dead.
If it is hard to read names, “Right Click” the picture and open the image in a new tab or save the image. If on mobile, you can save the image or pinch-zoom.