The time-lapse video made by Harvard Medical School shows a "mega petri dish" plated in black ink. The huge 2' x 4' petri dish (dubbed Kishony's 2-by-4, from Professor Roy Kishony, whose lab was used in the experiment) is divided into 9 vertical bands. Each band was given successively higher doses of an antibiotic, starting from 0 in the outermost bands, gradually increasing to 10 times, 100 times, up 1000 times in the middle band.
Starting from the outermost bands, a white bacterial (E.coli) colony begins to move. The colony slowly creeps towards the middle, from both sides of the petri dish — an eerie white stampede across a field of black. As it reaches each band with increased levels of antibiotics, the bacteria momentarily stops, until a mutated, immune bacteria picks up the pace and begins creeping again. This continues until the center of the petri dish, with 1000 times the amount of antibiotics, the last line of defense, turns completely white.
The regular bacteria has evolved into a superbug right before your eyes, creating one of the clearest visualizations of evolution.
It's a reminder, literally in black and white, of how bacteria can mutate be immune to even the strongest doses of antibiotics.