Simplify the following text for a Grade 11 native English-speaking person.
Original: Jake Shields ( born January 9 , 1979 in Mountain Ranch , California ) is a American mixed martial artist that currently fights for the UFC in the welterweight division .
Simplified: Jake Shields ( born January 9 , 1979 ) is an American mixed martial artist who is currently fighting in the welterweight division of the UFC .