No, you don't. You can play Evolution Planet without using a Facebook account. You can even play without an internet connection. However, if you do decide to play using your Facebook account, there are certain advantages to it:
• Your progress in the game is being saved in the cloud, which means that you can continue with your ongoing matches regardless of whether you switch to another device.
• Playing with friends is so much more fun! You can compete with them, fight them for the highest score on each level and always know about their progress.
• Your friends can help you by sending you lives and map pieces which are used for unlocking new islands.
• Your gems and powers are being synchronised between all devices you have connected to your Facebook account.
• Evolution Planet will NOT publish anything on your wall without your permission.