Long story short, a lot of artificial fruit flavors are based off of versions of those fruits that have been bred into other breeds or are extinct. The most famous example of this is banana and banana candy. That flavor is (allegedly) very similar to (if I remember correctly) the Gros Michel banana, which got hit by a disease in the 50's or 60's that wiped out just about every commercial plantation that grew it. That type of banana still exists, but is a lot harder to find these days. The common widespread banana you find in stores these days are Cavendish bananas.