<i><b>The Evolution of Bacteria on a “Mega-Plate” Petri Dish:</b></i> 
Bacteria (white) grow on a large petri dish with increasing concentrations of antibiotic (<a href="https://en.wikipedia.org/wiki/trimethoprim" class="extiw" title="w:trimethoprim">trimethoprim</a>) in bands towards the center. Evolution of antibiotic resistance can be seen as mutants with higher antibiotic resistance are able to colonise the more central regions. By the 11th day of evolution, variants with 1000x higher antibiotic resistance have colonised the central band. Film played at 18000x speed (covering 11.7 days total).
<a href="//commons.wikimedia.org/wiki/User:Rkishony" title="User:Rkishony">Rkishony</a> - <a rel="nofollow" class="external text" href="http://kishony.med.harvard.edu/">Kishony Lab</a>, Harvard Medical school &amp;  Technion, Israel Institute of Technology
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<span class="int-own-work" lang="en">Own work</span>