Atmospheric density defines the mean inertia, more energy is required to create a wind effect an said wind effect has more energy..but equally at every moment requires more energy to maintain itself against the inertia of standing bodies of air.
Wind is largely the result of different localized average air pressures, or in other words.. the average density alone neither increases nor decreases wind speed nor wind effect.
Atmospheric density is not any different to working with any other density.
Imagine you're in a swimming pool and, with your arms submerged do a "shinku hadoken" maneuver.. water is propelled forward..but it doesn't maintain it's force indefinitely because of the liquid's resistance & the dispersal of energy.
Talking about adaptation, I can't see any land dwelling organism evolved in terran conditions operating under such conditions.
Lungs would need to use [more than] 12 times as much force to expel air from a filled lung in the cycling process. Lungs would be filled, in turn, with air being motivated by that (considerable) difference in force created by the 12* air pressure, which would quickly damage human lungs, for instance.
Organisms would require significant increases in malleability/density or some other mechanism or structural property that diminishes the destructive effects of external pressure. Diving whales are good examples of approaches to this, the replacement of bone with cartilige, using fluids at high density to balance pressure loads etc
Insect approaches to 'breathing'(more like fish respiration than mammalian) would become the norm, I'd imagine, though we could imagine other approaches made viable, large & cavernous lungs probably never would be unless fitted with significantly superior valves to land-base terran life.
Eyes just wouldn't work, or at least.. those formed under terran conditions would degrade quickly, pressure deformations could be adapted to of course, potentially, tho a species transplanted would likely just go permanently blind as it had no use for it's eyes, babies would lose the use of them before they learned to talk.
If we think about heat-exchangers in terran organisms we have more issues, I don't think humans would be able to sweat, for instance and would heat up and die, adaptations would include ..being cold-blooded and restricting the amount of heat generated under normal operating conditions. more efficient heat-exchange mechanisms, or at least those that can operate efficiently at high pressures.
For creatures evolving under such conditions, the emergence of intelligence is massively [even more] unlikely.
I'd go with: The dominant lifeform would be dinosaurs, amphibious and retain piscine eyes.
In fact, wasn't the atmospheric density of earth supposed to be much higher than the modern era due to higher mean temperatures and thus more water in the air? So, are we describing ancient earth? :)
//reply to comment.
Well, I think that's true, because actually you never need to empty the lungs, your 1/12th 'normal breathing effort' is potentially enough to exchange the same number of actual molecules. That is to say..not having to empty your lungs is a factor I was managing to totally overlook.
But we have other problems.
Firstly that if we assume the same effort to each breath, it seems reasonable to assume we're exchanging just over 1% of the lung capacity in any given breath.
Whilst we might be getting the effective oxygen/moisture/general goodness content exchange of a normal breath, the proportion of 'stale' air in the lungs will be considerably higher. Then we get to diffusion in the lung membranes and etc, wherein the pressure difference between the interior of the lung (that is to say it's capacity) and the exterior (that is to say the body proper/exchange mechanisms between the lungs and rest of the body is significantly increased.
Whilst I'd suggest that this might increase the rate of uptake, I'd assume this to be 'across the board' and not just goodness..an result in poisoning, if nothing else.
Hearing is another thing of course, naturally sound waves act differently in different densities of matter, they' still work, but what we heard would be different.
I didn't finish high school, so take all that with several pinches of salt.