BluRay played in a standard DVD play?

I messed up at Walmart a few minutes ago in thinking the cheaper 19.95 disk was the standard format. I think I know the answer all ready (ie: get my butt back there and exchanmge it for the right one tomorrow).
But I gotta ask the dumb question: Is there a codex for playing the aforementioned BluRay disk on a standard DVD player. HD isn't an issue. I know the players will upgrade a non bluray. can it work in reverse. It would be nice to learn how to train my dragon, even in standard format without the run and save the disk for the next jump into the new tech.