Caption: A schematic diagram illustrating the increase in antibiotic resistance in a sub-population of microorganism by natural selection---i.e., evolution in action.

Credit/Permission: User:Wykis, 2007 / Public domain.
Image link: Wikimedia Commons: File:Antibiotic resistance.svg.
Local file: local link: evolution_microbes.html.
File: Biology file: evolution_microbes.html.