Large Plastic Plates??? Novice Question

First of all I would just like to say that I know nothing about cars, so this is probably going to be a really simple question.

Underneath my '02 Camry directly beneath the engine there are two large overlapping plastic plates. The corner of the bottom one tore loose and is dragging on the ground. Do these plates actually do anything? Do I need to replace it, or can I just take the one off and not worry about it?

I would cut off the piece that is dragging on the ground and then replace the engine cover when you can. It keeps road crap from getting into your engine compartment.

I don't have the tools to cut through that thick plastic, so I just took it off and I'll have to order the new one as soon as possible. Anyone know a good place to buy them? Or specifically what they are called?

Not sure, but I bet it is an engine cover.