Hi Lynn
Thanks for finding this family tree, but there is a good reason why unsourced family trees are considered not a reliable source, particularly for pre-1700 profiles, because it basically looks like someone has just thrown together all the Kerr profiles without anything to confirm they are connected.
For instance, Robert Kerr, 2nd Earl of Lothian didn't have a son David (see The Scots Peerage, vol. 5, p. 460) and even looking at later Kerr families of Earls of Lothian, I can't see a David (for instance in pages 473-475 are grandchildren of 2nd Earl of Lothian who are born about that time period).
Also in that family tree, David Kerr seems to be married to two different women on same day. Usually unsourced family trees can be good for hints, but I not even sure I would want to do that with that particular tree.