AF-S lens on Nikon DSLR bodies with AF motor

Hi all,

I would like to check that when a AF-S lens is mounted on Nikon DSLR bodies with AF motor (ie, D50/70/80/90..), will the auto-focusing be driven by the AF motor on the lens or driven by the DSLR body?

If its driven by the AF motor on the lens, how would mounting the AF-S lens on a D90 be different from a D300/D700?

Just wondering and hope someone can enlighten me.

Thank you.