Let its referent or meaning be another frequency. Neither frequency is a concept, just a natural pattern. The system associated with MacKay information is any living organism. Since no conceptual interpretation is imposed on structural information, it and its associated system can be considered as much more generalized than the rival types of information. This generalization is key to quantifying Aquinas' two level existence.
Evolution involves lower life forms, starting with single-celled organisms.
The only type of information that these organisms can use is MacKay information. This conclusion elucidates the argument for Darwinian evolution over creationism.