is describe the evolution of a song

I am not musical but I am always interested in where songs come from.  When I heard K'naan's version of Bob Dylans "With God On Our Side" I was fascinated by how he had not just covered the Dylan song but had taken the theme and the melody and turned it into an entirely different song much like Dylan did with a song called The Patriot's Game.  In fact K'naan's song is less of a copy of Dylan than Dylan's is a copy of Patriot's Game.

Here's The Patriot's Game a song about an IRA rebel.  (You don't have to listen to the whole song to get the idea.)

Now the Dylan version which asks whose side god is on in various conflicts.

and K'Naan's version. Unfortunately I can't find the entire song but this is a short sample.  When you link to the site you have to click on play sample.


http://www.amazon.com/With-God-On-Our-Side/dp/B006W5JPSU