Hold on! I agree that the term natural selection is confusing and misleading here.
But there certainly are selection pressures for events other than biological ones. Here's one: There is significant pressure for a trickle of water to follow depressions in the ground rather than small hillocks. Another: There is pressure for a planetoid to end up in certain orbits around its sun. How about: There is pressure for mountains to appear where tectonic plates are compressing.
In all the cases I cited above, certain objects disappear if they do not happen to "follow the pressure."
~~ Paul
I think you might be misapprehending pressure in this context. Living organisms do not conform by being beaten down, as in water in a graviational field or pebbles being rounded.
Living organisms persist only if they can continue to accrue energy. The original competition was in who could actually reproduce, and at that time the only energy was in other organic molecules. The original was chemical evolution by sustained reaction. The more molecules that accrued, the more chance of persisting; rather the antithesis of rocks being beaten down. It would be as if rough rocks had a better chance of washing downstream; you would end up with more rough rocks than not in a given environment. The rounding is not a selection pressure; the differential is.
Now, this is not to say sedimentation is evolution; it represents a selection pressure. A sieve in sand is similar in this regard, as there are some grains that get past while some do not. But this is only part of the equation; it is selection pressure, it is
not evolution. Evolution comes about when there is more than one molecule vying for available energy as a means of survival. The larger ones persist, then the ones that can fold so they are harder to break apart, then the ones of those that can more efficiently fold and unfold with temperature changes to both guard and assemble more energy. Eventually, some have folding sequences that curve and actually cover other sequences during vulnerable times, or that form a ribozyme that clips at other sequences (the first predator).
From there it is steps along the way, with selection pressure being the gate, but mutation and reproduction being the driving force to create a new generation. Without change, a new selection pressure could cause an end to this process. Without reproduction, the process stops.