What is the icon on lower right?

What is the icon on the lower right with profiles of pokemon (profiles colored in for one's I've caught). And what happens when I select one of the profiles?

Edit the icon on the home screen (while walking around). It shows three pokemon profiles, and if you click it it says "nearby" on top

This bar shows the three Pokemon closest to you. If you tap it, you will see up to 9 (sorted by distance), and if you tap one of the Pokemon in that list it will "focus" on it -- then only that Pokemon will show in the bar, along with it's footprints (distance).

Note that the Nearby list (when you tap the bar) is sorted from closest to furthest left-to-right, top-to-bottom, but the bar itself appears to be sorted in reverse, so the rightmost Pokemon visible is the closest Pokemon.

You can here sort your Pokémon by:

• Most recent catches
• Favorites first
• Number (Bulbasaur = 1, et cetera)
• Max HP
• Name
• Combat Power