The following video was made by Dr. Martin Ackermann, SNF Professor for Microbial Evolution, Theoretical Biology Department, at ETH Zürich, Switzwerland.

The video was made as part of a study of aging in bacteria. It was believed that bacteria never "grow old", but keep dividing forever. If
you watch this video very carefully, however, you can see that some of these bacteria divide 5 or 6 times, but then stop dividing.

See the Exponential and Logarithmic Functions interactive.