Which came first, the chicken or the egg? As philosophical questions go, this one is pretty lame as it is straightforward to answer. Paleontologists are always hip to answer this question. But since I don’t know any hip paleontologists, I’ll answer myself.
The answer is clearly egg. The chicken gene evolved about 70 – 90 million years ago (according to a 1989 paper by Cracraft and Mindell, which I’m too lazy to actually find and read but found a recapitulation by Vandergon and Reitman).
In contrast, we (and by we I mean not me) have found fossilized amniote eggs (which are similar in nature to a chicken egg) that are dated to be about 140 million years old, and amniote eggs are recognized to exist at least 340 million years ago. Other types of eggs date back even further, but that’s not really the same thing (in the same sense that omelets and caviar are not the same thing).
So, egg clearly first.
Still, one might argue that “chicken or egg” clearly implies a chicken egg, not any type of egg. So if we assume we really meant “Which came first, the chicken or the chicken egg?” then the question gets a little more tricky. There is no clear delineation between the first chicken and the not-quite-a-chicken parent. The argument at this point usually spirals into whether the definition of a chicken egg is an egg containing a chicken or an egg that comes out of a chicken. Regardless, the first thing we would classify as a chicken was undoubtedly hatched from an egg, so therefore the egg must have come first.
Unless, of course, you don’t believe in all that evolution crap. In this case you get a different, although equally simple and definitive, answer.