In one paragraph describe the positive and negative effects of the Columbian Exchange.

The term "Columbian exchange" was coined by historian
Alfred Crosby nearly 500 years after Christopher Columbus' first voyage to the New
World. The term refers to the exchange of items and ideas between the Old World and New
World following Columbus' journeys. The exchange included animals, plants and cultural
diversities that helped to launch an "ecological revolution" beginning in the early 16th
century. Virtually every group of people in the world was eventually affected--in mostly
positive, but also in negative, ways. New ideas concerning agriculture and the infusion
of new crops and plant species helped to feed the people of the globe and increase the
population. New items such as corn, potatoes, peanuts and tomatoes became staple crops
around the world. Europeans introduced many new species to the New World, including the
horse, sugar cane, oranges and coffee. But the diseases brought to the New World by the
Europeans drastically reduced the population of many cultures, who had no immunity. The
appearance of the disease-carrying brown rats were unknown in the New World until their
arrival on European ships, and many forms of unwanted plant life, such as Kudzu and
Dutch Elm Disease, found their way to new lands.