The “Columbian exchange” is a phrase coined by Alfred Crosby through his 1972 book of the same title. It refers to the process by which living organisms—including people, animals, plants and their products, and microbes—moved between the Old and New World after Columbus arrived in the Caribbean. The positive and negative effects have often been considered to balance each other, and a given effect can be perceived as positive or negative depending on the perspective of those initiating it or affected by it.
The exchange of peoples was initiated from 1492 onward. Europeans, Africans, and Asians serving on the crews of the European ships all soon arrived in the New World; almost all of them were men. Sexual relationships with indigenous women began the process of “racial mixing.” Captives and slaves from New World peoples were taken to Europe on the early return voyages. Although the large-scale enslavement of African did not begin right away, the idea that additional labor was needed in the New World did take hold and provided much of the justification for slave systems. After the Pacific was crossed, the direct movement of Asian people to the New World from the East was greatly facilitated.
Most often, however, “Columbian exchange” is used in reference to diseases, crops, and domesticated animals. Crosby was initially stimulated to conduct the research by his interest in smallpox. The negative effect of this particular disease was part of a larger array of communicable diseases, including venereal disease, that wreaked havoc on New World peoples who had no immunity. The depopulation of the Americas through disease was rapid and severe.
Crops, in general, created positive effects. From the New World, maize (corn) and potatoes, the two most important subsistence crops, made their way to the Old World. In the other direction, wheat, barley, rye and related grains, as well as rice, were particularly important. Europeans also took varieties of grapes to make wine, as well as olives. Spices, which yielded a good price for very low weight, were traded in both directions.
In terms of animals, large draft animals were virtually nonexistent in the New World: No horses, no oxen or cattle. The Europeans took horses on their earliest expeditions, and the horse both transformed warfare and peacetime. Cows, sheep, and goats yielded meat and, to some extent, milk—especially important as cheese, which could be more readily stored and transported. The large New World animals, bison and camelids (alpacas, llamas, and others) were not suitable for draft animals, and the llama had no advantage over its Old World cousin, the camel, as a beast of burden, so these animals made little impact on the Old World.
In terms of small animals, domesticated fowl existed in the New World, but they were largely replaced by Old World varieties, especially chickens. One of the negative consequences was the extinction of some native species as raising and breeding them declined.
The overall context of the exchange, however, is its single most important positive effect. Soon after 1492, the world would be understood as a globe. Initially, although Columbus brought or sent back products and people to Europe, it was not immediately accepted that the world was not flat and that it was much larger than previously believed. Many people believed that Columbus had arrived in Asia or that it was only a short distance from Hispaniola. The impetus to exploration and trade, resulting in the 1522 completion of Magellan’s expedition’s circumnavigation, opened the entire world to continued interaction much as we know it today.