Based on the readings assigned in class (McCant, Gerges) and lecture notes, what are the differences between ISIS and Al-Qaeda?

References:

2. William McCants, The Believer: How Abu-Bakr al-Baghdadi Became Leader of the Islamic State, Brookings paper, 2015

http://csweb.brookings.edu/content/research/essays/2015/thebeliever.html