Lion brought with it many iOS like advancements; enhancements to Multi-Touch Gestures, Full Screen apps, Launchpad, Resume/Auto Save/Versions, an iPad like Mail interface, iCal and Address Book highly styled like the iOS counterparts, auto termination of applications again borrowed from iOS, reversed scrolling to better match up with touch screen devices, and many more things that all spell out one thing; OS X is borrowing heavily from the design of iOS.

Source: Mac Appstorm