Well, if you look at it purely from a functional design standpoint, more intelligence and problem solving ability than is required to obtain food, avoid predators, and to breed successfully is a waste of resources. Seeing the beauty in a sunrise doesn't put potatoes in your stomach.
I meant "superior" in a moral or larger sense of having more of a rightful entitlement to dominion.
In the line of thought you have taken, the life form that is most able to dominate over an ecosystem would be described as the superior one whereas it is only superior in the sense of propagating its DNA most efficiently in the biosphere and achieving the status as the top of the food chain.
The alien life forms presented in the original remake of "The Thing" (with Kurt Russell) or in the "Alien" series of films represent what happens when DNA develops to the point that the creatures it manifests in the biosphere are the ultimate Alpha Predators.
There is no moral component to DNA. DNA will readily condemn a creature to a life of agony or ecstasy without regard for anything except manifesting the characteristics which confer upon it the best chance of reproducing as the dominant species. DNA does not care how it accomplishes that task.
There are more species of wasps than any other insect (thousands), and that is because they have one of the most efficient methods of reproduction - they have the utterly disgusting proclivity to lay their eggs in the living bodies of hosts, and the larvae then feed on the host while it is still alive. Very efficient and completely barbaric. In fact the wasp was one of the animals upon which the xenomorph in the Alien movies was based.
There is a great old Outer Limits (Original Series) episode titled the "Keepers of Purple Twilight". The story is about a brilliant physicist who is offered an answer to a problem he is stuck on if he will simply allow an insect-like alien life form to "borrow" his emotions. The theme of the ultimate purpose of life and the question of what constitutes a "superior life form" is explored very nicely in that short episode. It may be viewed on YouTube or Hulu for free, I believe.