No - he is not singing the book, but Chris Smither is indeed talking about origin of species (tip from a Simple Prop). A nice mixture of science & religion in a little over three minutes (see lyrics here). Actually this song is played quite a bit on our local (fantastic) radio station, 93.9 - The River (If you are not familiar with the station, check it out. You may find an interesting mix of music here).
Here is Chris Smither:
Well...we can all find support for his version of Intelligent Design. By the way, this song was included among the 100 best songs of 2006 by Rolling Stone.