Why some invaded

Big domesticated animals
Europe had a lot, but the New World had llamas.

Agriculture

• Low protein corn
• Hand planting
• Hand tiling
• No animal aide for irrigation or milling
• Lack of manure for fertilizer

Germs

• Diseases took 95% of the native population
• Germs are a byproduct of animal husbandry
• Agriculture societies - high density, live near waste, rampant plagues

Technology

• Ships and Navigation (idea diffusion)
• Steel
• Weapons - advanced in the crucible of Eurasia
• Water and wind power
• Wheels & animal transport
• Writing

Organization

• Central political structure
• Allowed for large, risky endeavors.
• Central religion could galvanize diverse groups