
Its just variation within a thread.  The variation at times has been so great
that speciation has occurred.  So Albert Sabin is the common ancestor of
several threads, some of which have themselves speciated.  On a separate topic,
I subscribed to t.o. just recently.  Albert Sabin existed at that time, so I
have no clue as to its origins.  Maybe the abiogenesists have an answer.  I
might also point out that evolution is aimless.  Thus why Albert 
Sabin evolved into a religious discussion is probably unexplainable.