A subdivided rock may actually be sand. Or were it silver ore, some of the subdivided rock is silver and some slag.
Sure, Doc, it might be. The point about the rock and the type of system in nature that it represents is that it is divisible into fairly uniform units of itself (chemically speaking) of whatever size; yet there is little variety, if any, from unit to unit, so to speak. If the units get small enough, we can start to speak of "sand." The point is the chemical composition alone is what makes a rock what it is, or its sand if it's ground up fine enough.
But the rock is a different system in nature from a living organism. Living systems are not divisible into uniform components. Indeed, living systems are composed of an enormous number and variety of other living systems -- cells, tissues, organs, etc. -- that all must "work together" in order to express that particular living system. This "work together" business strong suggests the existence of some kind of "global governance," which I imagine must be information-based.
If one reduces a rock down unto sand, I don't think much changes, thermodynamically speaking. But if you start to cut up a living system, the matter of which it is formed instantly begins to try for the shortest possible route to thermodynamic equilibrium. If it loses its information source, then it returns to the "captivity" of the least action principle; in other words, it is returned to the governance of the physical laws alone.
In short, the loss of information is what sets up the "heat death."