Wikipedia is not accepted as a valid source, and worse, copy and pasting is considered plagiarism. If a teacher searches a line from your paper and finds the Wikipedia page, you will be in a lot of trouble.
Dude, I would've been expelled if I tried that crap o.O Some school's even check if the paper resembles anything that's been published, or previous student essays, and whether it's just a coincidence or intended. Not to sound preachy, but don't do that anymore, or you'll eventually get into serious trouble.
What those guys said. Also, one of my friends once got accused of plagarism 3 times because some lines in her essay vaugely looked like a previous student's work. The line was something like "The main themes of the book are love, hate, death and sparkleberries." (Okay, I have no idea what she wrote and the word "sparkleberries" definitely wasn't in there...), basically what any student could have wrote. The most basic sentences can be used to get you accused of plagarism. It's weird.
