Carrots are mutants.
Well, orange carrots at least. Originally, purple carrots were the norm, but there were some offshoots. Yellow and white ones appeared in the wild. Over time, 17th-century Dutch carrot growers managed to cultivate these yellow and white ones carrots into the orange ones we're familiar with today.
The purple ones still do exist, but they're by far the minority in the world of carrot colors. Want to try some? Beware — there may be a good reason why purple carrots are now the uncommon breed: the orange ones taste better. In fact, orange carrots may be a superfood of sorts when it comes to taste. A 2010 study showed that children said foods tasted better if favored cartoon character appeared on a box, with one food excepted: carrots.
See Also: Where Do Baby Carrots Come From?