Thanks. That makes sense, and goes along with the whole idea of having dominion over the earth ... But seriously: has "cut[ting] a chunk of meat out of a living cow and 'save[ing] the rest for later'" ever been a problem anywhere? On the one hand, I've heard of some really wierd culinary practices, particularly in the Far East (but never that). On the other hand, Biblical prohibitions tend to have a discernible basis in somebody's documented misbehaviour.
There was probably a lot of that going on during Noah's time, before the Flood. ;)