Manioc is so prevalent in Africa that many Africans swear the plant is native to the continent, but it isn't. Nor are sweet potatoes, and while New World grains never replaced rice in Southeast or East Asia, the sweet potato is so common that it is known as the poor person's staple in China. Even in Japan, the tomb of the farmer who is reputed to have first brought them to the islands is known as the Temple of the Sweet Potato. And it's also worth noting that corn, while it may not feature prominently in European diets, has been the central source of food for animals in Europe for centuries. And in fact, that's still the case. In 2005, 58% of the corn grown in America went to animal feed, is the kind of thing you learn when you live in Indiana. Alright, so last but not least, the Columbian Exchange involved the transfer of lots of people.