This is the bottom line:
the issue is that you need to evolve many many complicated things all of which work together (if engineered just so) but which are useless by themselves.
I have no clue what the explanation is, nor do I need to. I only know that Darwinian evolution, as best I understand, can't really explain things like this which include the hearing mechanism, the visual system (from an anatomic point of view), and many other aspects from e.g. a physiological point of view. So I'm left saying I don't know what caused this, but planning by whatever (god, aliens, skynet, Hal from 2001) seems more likely. I'm open to other possibilities, but unless this is addressed, there is a whopping hole in evolution as an answer.
NB: I totally understand that evolution could certainly be true for everything and the answer to this solved at some later date and that this does not disprove evolution. IT is just that for now, one can't say it answers al the questions either.
Benko, I like that last part because the earlier paragraph sounds like "I don't get it, therefore the explanation is not complete." I certainly don't understand every detail of evolution, though not for lack of trying. Science is of course an ongoing explanation, and I think we've only begun to crack the code. Significantly, though, I have seen enough evidence to be convinced.
There is the old argument that begins, "What good is five percent of an eye?" (Answer: better than zero percent!) And with hearing bones and other specialized parts, it is tempting to say they are designed by a sentient being rather than simple physical laws acting on biology (biophysics) over millions of years. Just as you leave it open that evolution could
be the answer, I have to concede that there could be an alien designer. But then who designed the designer?
Speaking of simple physical laws, I love the opening to one of Richard Dawkins' books that talks about how the tide can arrange stones on a beach. He suggests that a primitive tribesman might look at the orderliness of it and draw the conclusion that a god made it happen, while we will smile smugly and explain how a completely natural process brought about that order. We may know a lot more than those primitive tribesmen but with hearing bones we might not totally grasp the "tide" that made them. But someone out there might.
Furthermore, the reason I chose hearing bones as a example is because while they may look like they were specifically designed for hearing, we can see that some of them were in fact jaw bones. Nature is not efficient in this way, but it loves redundancy and multipurposeness. That's why we swallow and breath with the same throat, whereas a designer could have circumvented the possibility of choking on tater tots.
Whether we were designed or evolved, it gives me a sense of wonder to think about how we came here from Nothingness.