"The College Food Chain" joke

I found this on a wall at Iowa State University.
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THE DEAN
Leaps tall buildings in a single bound
Is more powerful than a locomotive
Is faster than a speeding bullet
Walks on water
Gives policy to God
THE DEPARTMENT HEAD
Leaps short buildings in a single bound
Is more powerful than a switch engine
Is just as fast as a speeding bullet
Talks with God
PROFESSOR
Leaps short buildings with a running start and favorable winds
Is almost as powerful a switch engine
Is faster than a speeding BB
Walks on water in an indoor swimming pool
Talks with God if a special request is honored
ASSOCIATE PROFESSOR
Barely clears a quonset hut
Loses tug of war with a locomotive
Can fire a speeding bullet
Swims well
Is occasionally addressed by God
ASSISTANT PROFESSOR
Makes high marks on the walls when trying to leap tall buildings
Is run over by locomotives
Can sometimes handle a gun without inflicting self-injury
Treads water
Talks to animals
INSTRUCTOR
Climbs walls continually
Rides the rails
Plays russian roulette
Walks on thin ice
Prays a lot
GRADUATE STUDENT
Runs into buildings
Recognizes locomotives two out of three times
Is not issued ammunition
Can stay afloat with a life jacket
Talks to walls
UNDERGRADUATE STUDENT
Falls over doorstep when trying to enter buildings
Says "Look at the choo-choo"
Wets himself with a water pistol
Plays in mud puddles
Mumbles to himself