On addition to the other answer posted, the Columbian exchange also traded slaves from Africa to Latin America as well as brought diseases to the natives, a large factor in the death of natives in the New World...which led to Africans being brought there. The Spaniards needed workers and the natives they enslaved were dying of disease and poor treatment, so they imported replacements. Guess I'm getting off topic.
The Columbian Exchange was when the old world (Europe) trade with the new world (America) items. for example: Old World had horses. So if Europe never came to America... we wouldn't have them. Or new world had tomatoes. If Europe didn't have tomatoes... We wouldn't have pizza or delicious Italian goods.
Madison favor giving the larger states representation according to population because he did not want the small states to wield disproportionate power.