AP Human Geography College Board

Agricultural Origins and Diffusions

Agricultural Origins and Diffusions

Introduction to Agriculture

• Agriculture refers to the planned cultivation of plants and rearing of animals for sustenance or economic gain.
• It revolutionised human existence, allowing permanent settlements (sedentism) and population growth.
• The origins of agriculture are found within the Neolithic Revolution, which took place around 10,000 years ago.

Theories of Agricultural Origins

• Carl Sauer proposed that agriculture originated in areas where plants and animals were naturally abundant - the oasis theory.
• The Demic Diffusion theory posits that agriculture spread via migration of farming communities.
• The Cultural Diffusion theory suggests that the knowledge and tools of farming spread among cultures without large-scale migration.

Primary Agricultural Hearths

• Key hearths of agricultural origin include the Fertile Crescent, Sub-Saharan Africa, China, and the Americas.
• The Fertile Crescent (including parts of present-day Iraq, Syria, Lebanon, Israel, Jordan) was a primary hearth, with agricultural activities like wheat and barley farming, and goat and sheep herding.
• Mesoamerica was a key hearth for maize, beans, and squash (the Three Sisters).

Diffusion of Agriculture

• Agriculture diffused outwards from these hearths by various methods: relocation diffusion (through migration) and expansion diffusion (through the spread of ideas).
• Expansion diffusion includes both hierarchical diffusion (from larger to smaller groups) and contagious diffusion (among neighbours).

Impact of Agricultural Diffusion

• The diffusion of agricultural practices transformed societies, landscapes, economic structures, and global ecosystems.
• The Columbian Exchange was a significant event in agricultural diffusion, involving the global transfer of plants, animals, diseases, and human populations between the New World and the Old World.
• New agricultural practices can act as a double-edged sword, causing a rise in food production but also leading to deforestation, loss of biodiversity, and environmental degradation.