THE COLUMBIAN EXCHANGE
Most modern plant and animal species evolved on one continent or another, only occasionally occupying more than one at any time. Human beings also evolved. After migrations across land and ice bridges, modern human civilizations developed in distinct ways on different continents.
The traded items that comprise the Columbian Exchange are traditionally broken down into four categories that include domesticated animals, domesticated plants, infectious diseases, and culture/technology. It was never an even exchange. Either the Eurasians or the native populations of the Americas would benefit more.
The final two categories were, without a doubt, detrimental to Native American peoples. While syphilis moved to Eurasia, the following infectious diseases decimated New World populations who had no natural immunities: chicken pox, cholera, influenza, leprosy, measles, scarlet fever, smallpox, typhoid, typhus, yellow fever, the plague, malaria, and even the common cold.
Whether the Columbian Exchange was beneficial or not, it was certainly unavoidable. Discovery, exploitation, subjugation, and transformation of the strong over the weak are distinctly human phenomena.