It's not unusual for us to be struck by the amazing ways in which life on earth has adapted to its environment.
Common examples include the ability of flowers to follow the sun or vines to snake their way along trellises, but a more mundane example may surprise you even more. For example, did you know that potato roots can tell which way is down?
Leave a sprouting potato in a dish and wait until its roots are all reaching downward, then turn it on its side. Within only a few hours, those same roots will begin adjusting themselves to point downward again.
In fact, research has shown that as little as two minutes of being turned in a new direction will start roots reorienting themselves. How does this happen?
The answer seems to be found in tiny concentrations of starch inside the root itself. These heavy starch packets sink to the bottom of the cells in the root's tip. In that way, they always show which direction is down. Furthermore, the packets compress the end of the cell where they are resting, triggering a hormone in the root that slows growth only on that side.
Now, imagine a potato root lying sideways, with the top half of the root growing faster than the bottom half; the root will start to bend downward. Not bad for a spud.