What you stated is basically how I unserstand evolution, I was just amazed by the article's statement: We want to differentiate between the genetic capacity in each species genome that permits it to change with the environment as being different from changing to some other creature.
And was curious how they could define a "genetic capacity" when one of the things evolution could do is change the "genetic capacity", and what would regulate such "permission to change" if such permission is contained in DNA and thusly could itself be changed ...
It is the same mentality that would pictures the start of a marthon, the middle, and the end just see a bunch of steps and no journey.