A friend of mine wrote to me as follows:
I was told about the following question, raised by Rabbi Yaakov Feit, who was in a museum containing the remains of Lucy, a famous proto-human. He wanted to know whether a kohen could enter the museum, or, equivalently, whether Lucy's bones are halachically considered to have come from a human corpse (in which case they are metamei be'ohel).
I thought this question could be broken down into several interesting components.
1. Are these bones actually the remains of an organism? Adherents of Gosse theory might say that bones carbon dated as millions of years old were simply placed in the earth, as bones, by God at Creation, and never belonged to a living being. My friend and I assumed that bones that are not remains of a living being are not metamei, though we weren't sure how to prove it.
2. Is carbon dating halachically recognized? (Not sure why it shouldn't be, but....)
3. If Lucy lived (and died), was she human, or at least human enough to be metamei? This gets into the whole adnei hasadeh business, etc. Note that apparently there is an opinion (Chasam Sofer?) that the remains of gentiles who lived before Matan Torah are metamei be'ohel mideoraisa, even though the remains of gentiles who lived after Matan Torah are not. So this might be a nafka minah mideoraisa.
I thought this was a really interesting question, because it shows that these topics have practical--and not contrived at all--nafka minahs lema'aseh. It shows that even among those who read Genesis literally and assume the earth to be mere thousands of years old, there are still nafka minahs lema'aseh deoraisa between the various approaches. It makes a big difference whether ancient bones were planted in the earth by God, or whether they were, for example, made to look much older by the Flood (in which case they could still be assumed to be actual remains of once-living organisms). There are probably lots of museums affected by this consideration. It shows that belief in an ancient earth can have practical ramifications. And it shows the importance of paleontology in psak halacha: you can't pasken whether Lucy is metamei now that she's dead until you figure out what she was when she was alive!