What is the difference between pilates and yoga?!

What is the difference between pilates and yoga?

I just wanted to know and I was wondering what the difference was. I was thinking of taking a class and I want to know which is better for a 13 year old girl that is slightly overweight?

Yoga, is aimed to unite the mind, the body, and the spirit. Yogis view that the mind and the body are one, and that if it is given the right tools and taken to the right environment, it can find harmony and heal itself. Yoga therefore is considered therapeutic. It helps you become more aware of your body's posture, alignment and patterns of movement.
Pilates seek to reach much the same goals, also via a series of controlled movements. The major difference is that the Pilates technique not only has a full complement of matwork, but it incorporates work on the Pilates machines. The emphasis of the exercises is to strengthen the abdominals, improve posture, stabilize and lengthen the spine, improve balance and overall strength. Pilates gives you a longer, leaner, dancer-like line.

The question is, will they help u to loose some weight?
In order for Yoga or Pilates, or any other form of exercise, to assist with weight loss, it has to be accompanied by a well-balanced, carefully monitored diet. For the body to lose weight, it must burn more calories than it consumes. While this seems a simple enough concept, many people mistakenly believe that any form of exercise will initiate weight loss regardless of what they eat. The truth is, you have to be participating in an activity that actually burns off more calories than you are consuming each day, making a healthy diet equally as important as the form of exercise you choose.

Good luck.