What Crossed the Atlantic Westward in the Columbian Exchange

The Columbian Exchange (post-1492) moved species, diseases, and cultures between hemispheres. Westward (Americas → Europe/Africa/Asia) went the New World's biological wealth:

Plants (Domesticated Crops)

• Staples: Maize (corn), potatoes, sweet potatoes, cassava (manioc), beans (common, lima), squash, pumpkins.
• Fruits: Tomatoes, peppers (chili, bell), pineapples, papaya, guava, passion fruit, cacao (chocolate).
• Others: Peanuts, sunflower, tobacco, rubber, quinine (cinchona), vanilla, avocado.

Animals (Few Domesticated)

• Turkey (Meleagris gallopavo) — only major domesticated animal from Americas.
• Muscovy duck, guinea pig, llama/alpaca (Andes) — regionally important.
• Note: Horses, cattle, pigs, sheep, goats, chickens went EASTWARD (Old World → Americas). The source list had this reversed.

Diseases (Westward? Minimal)

• Syphilis (Treponema pallidum) — debated origin; strongest evidence supports New World → Old World.
• Most catastrophic diseases (smallpox, measles, influenza, yellow fever, malaria) went EASTWARD, devastating Indigenous populations.

Eastward Flow (Old World → Americas) for Context

• Crops: Wheat, rice, barley, oats, sugarcane, coffee, bananas, citrus, onions, grapes.
• Livestock: Horses, cattle, pigs, sheep, goats, chickens, donkeys.
• Diseases: Smallpox, measles, flu, typhus, malaria, yellow fever.
• People: Europeans, enslaved Africans.

The westward transfer of calories (maize, potato, cassava) fueled global population growth; the eastward transfer of germs collapsed American civilizations.