Where did the iPhoto 10 iCloud Photostream come from and how do I get rid of it?

I just updated my MacBook Air to mavericks. I have an iPad and iphone as well just updated to ios7. My Mac updated iPhoto as well. Now when I opened iPhoto I got my flickr and Facebook integrated folders in the left pane plus an iCloud photostream.

I didn't have that before and it has 287 pictures pulled from many devices but I didn't set that up. I only had/have a private photostream with a particular name and about 10 pics in it. this new one is just called iCloud photostream and it has 287 pics of which some I know I took with my iPad and others with my iphone. I of course sync both devices with my Mac so this pics are in my iPhoto library as well.

Where did the iPhoto 10 iCloud Photostream come from and how do I get rid of it?