According to the Gilder Lehrman Institute of American History, the Columbian Exchange was the exchange of plants, animals and diseases between the Americas on one side and Europe, Africa and Asia on the other. Many plants and animals now considered native to different countries actually were transplants and did not exist outside their region of origin before 1492.
Before 1500, potatoes and tomatoes were unknown outside of the Americas, while some plants, like bananas and oranges, did not exist on the American continent. What we now know as Colombian coffee was originally from the Middle East, while the rubber trees in Africa came from American stock. The two worlds also traded grains that became global staples, with the Americas providing corn and Europe introducing rice and wheat to the Americas. Much of the livestock exchange went in one direction, with explorers bringing horses, cows, sheep and chickens to the New World while introducing turkeys to Europe. The Gilder Lehrman Institute of American History states that diseases also found new victims to ravage through the Colombian Exchange, with smallpox in particular ravaging the Amerindian populations who had never before experienced the illness. On the other hand, there is some evidence to suggest syphilis originated in the New World, which proved to be a particularly difficult disease in Europe until the discovery of antibiotics.