shift+up received as <select>, breaking Emacs 24 "shift select" (like pc-select)

[Brett Hoerner]

If I start Emacs 24 with emacs -nw -Q in any (default configured) terminal 
editor like gnome-terminal or Terminal.app, shift+up is received as "<select>".

In other words,

C-h k <shift>+<right> = right-char
C-h k <up> = previous-line
C-h k <shift>+<up> = <select> is undefined

The problem is that shift+left,right,down all select/mark text in that 
direction in Emacs 24, but shift+up does nothing. Now, I'm further confused by 
how "shift" comes into play, since those are all bound to things like 
"right-char" not something like "mark-right-char". So when I go ahead and make 
a binding like,

(define-key global-map (kbd "<select>") 'previous-line)

It makes <shift>+<up> work as previous-line, but it doesn't select/mark the 
text like <shift>+left,right,down magically seem to.

I think I have two separate issues (or confusions) here. Any help is greatly 
appreciated.