Neo7: Since Linux distributions are open-source, everyone can modify or use a part of it. So do Apple. But I'm not sure if it has legal restrictions or not. Anyway, you're right. Apple is not that much creative (but I'm not against apple. I write these things now using my iPad )
BSD and equivalent licenses requires that derivatives must also also conform to the BSD (or others) license (which is not something that Apple does when it can avoid doing so).
There are so many features in Mac OS X that Apple has ripped off from Linux Distributions (KDE desktop application implementations are their favorite) and Apple advertises as "new and innovative from Apple" that it isn't even funny.
Hell if KHTML was not under QPL and GPL licenses, Apple would have killed it by making WebKit proprietary (and Google Chrome would not exist as it is today).