By the Numbers
Estimated population of Europe in 1492: about 60 million
Estimated population of the Americas in 1492: 40-100 million
Estimated population of Europe in 1800: 150 million
Estimated population of the Americas in 1800: 25 million (the vast majority of whom were of European or African descent)
Major domesticated animals in the New World in 1492: dog, llama
Major domesticated animals in the Old World in 1492: horse, cow, pig, sheep, goat, chicken, camel, oxen, cat, dog
Major edible plants unique to the New World in 1492: maize (corn), potato, squash, cassava (manioc), tomato, bell pepper, chili pepper, avocado, squash, pumpkin, peanut, chocolate, vanilla, strawberry, blueberry, pineapple, tobacco
Major edible plants unique to the Old World in 1492: wheat, oats, barley, lettuce, onion, garlic, banana, orange, lemon, peach, sugarcane, coffee, tea
Estimated number of Incas killed by smallpox between 1525 and 1532, when Francisco Pizarro conquered the empire: More than 200,0001
Estimated proportion of the Aztec population of Tenochtitlan infected by smallpox in 1520, one year before Hernán Cortés conquered the empire: 50%2
Potatoes in all of Ireland in 1491: zero
Tomatoes in all of Italy in 1491: zero
Peppers in all of Spain in 1491: zero
Strawberries in all of England in 1491: zero
Cocoa beans in all of Switzerland in 1491: zero
Peanuts in all of West Africa in 1491: zero
Cassava roots in all of the Congo in 1491: zero
Ears of corn in all of Europe in 1491: zero
Horses on the Great Plains of North America in 1491: zero
Coffee plants in South America in 1491: zero
Cane sugar plants in the Caribbean in 1491: zero
Fields of bluegrass in Kentucky: zero
Wheat stalks in all of the Americas in 1491: zero
Major diseases transmitted from the Old World to the New World after 1492: smallpox, influenza, typhoid fever, cholera, scarlet fever, yellow fever, malaria, measles, tuberculosis, bubonic plague5
Major