In 1650, James Ussher, the archbishop of Ireland, came up with a detailed timeline for all of the events in the Bible, going all the way back to the creation of man and the universe.
Familial (or domestic) genealogies were primarily concerned with inheritance and privileges of firstborn sons.
Our modern conception of genealogies is very different from how genealogies were used and understood in biblical times.
Some background information on genealogies is helpful in order to properly understand and interpret them.
This interest in genealogical identification is also seen in the time of King David and again in the time of return from exile.
At these later times, genealogies often were given in terms of other key historical figures (Aaron, Moses, David, etc.) rather than going all the way back to the patriarchs.