Well, some scientists propose that smell uses quantum physics:

http://www.ted.com/talks/luca_turin_on_the_science_of_scent....

(as I understand, Luca Turin's explanation isn't complete either - again it's a mix of different systems)

There's also the theory that birds detect magnetic fields through quantum effects:

http://www.newscientist.com/article/mg19826544.000-do-birds-...

Actually, I wonder if it's a coincidence that both of these are sensors.

I can't think of any other examples at the moment, but why would't life evolve to exploit quantum effects where it can?