I am coming to this "copying" discussion a bit late. I thought I would add
my two cents as well.
I teach observational drawing "draw what you see, not what you know" as my
mantra. I tell them if they copy they are stealing someone else's aesthetic
sensibilities as the original artist or photographer made aesthetic
decisions that are solely theirs. That said, on some work we do
'frankenstein' drawings. Which is to say if a student wanted to add an
elephant to their work, ideally I would say go to the zoo and do some
drawings and bring them back to work from. However that is not always
practical. So I tell them to bring reference material, which essentially
means 3-5 photographs of elephants. They are then charged to make
"frankelephant", or an elephant that is a composite of all of their
reference materials. In that way they are making the decisions as they draw
the elephant using reference materials.