What if the Columbian Exchange had gone differently?

Crops, animals and pathogens move between hemispheres, remaking diets and populations.

If it had gone differently: No potatoes or maize in the Old World; European populations stay smaller and hungrier.

1. 1600The potato takes hold in Europe, Northern Europe stays one bad grain harvest from famine; its population never surges.
2. 1740Europe's population boom, Without a surplus of hands and mouths, there is no cheap urban workforce waiting for the factories.