Hierarchy Where Art Thou

Rank me, tops of course
Save me, the undergraduate force
Remaining aloof
Unless the ladder is threatened
Conspicuously resume
Taking places
Flags and buttons
Pins and shirts
Show them up
Or you'll go down
And that's the key
Carved from teeth
That never runs
Out of speech
Saying: "Yes,
this is mine;
don't look sideways
at mighty frowns."