Hereof, what was one important effect of the Columbian Exchange?
Perhaps the most important impact of the Columbian Exchange was felt by the natives of the Americas. Large percentages of the native population died due to the Columbian Exchange. This came about largely because of the fact that the Europeans brought germs to the New World.
Likewise, what was the most negative consequence of the Columbian Exchange? Diseases were a huge negative impact. Diseases such as small pox and syphyllis were brought to the Americas by the Europeans and wiped out a large amount of the New World's population. While slavery had a bit of a positive light, it was mostly a negative thing.
Keeping this in view, why was the exchange of plants and animals between the old world and the new world called the Columbian Exchange?
As Europeans traversed the Atlantic, they brought with them plants, animals, and diseases that changed lives and landscapes on both sides of the ocean. These two-way exchanges between the Americas and Europe/Africa are known collectively as the Columbian Exchange.
Who benefited from the Columbian Exchange the most?
TL;DR: For reasons beyond human control, rooted deep in the divergent evolutionary histories of the continents, the Columbian Exchange massively benefited the people of Europe and its colonies while bringing catastrophic crumminess to Native Americans.