AP® Human Geography · Unit 5 · Topic 5.3
Agricultural Hearths and Domestication
Agricultural hearths are the separate regions where people independently domesticated wild plants and animals, turning them into crops and livestock through generations of unintentional selection.
Farming did not spread from one lucky village to the rest of the world. It started up on its own in several places, because people in different regions faced the same pressure: wild food was unreliable, and certain local plants kept showing traits worth saving. No contact was needed, because the raw material for domestication was sitting in each region's own wild landscape. Each hearth domesticated whatever wild species grew nearby, which is why the resulting crops look so different from place to place.
Domestication itself is not a single invention but a slow drift. Wild wheat shatters, dropping its seeds to the ground before a harvester arrives. A rare few plants held their seed heads together longer. Harvesters could only gather and replant the grain still on the stalk, so every planting cycle quietly filtered out the shattering plants and kept the non-shattering ones. Nobody was breeding wheat on purpose. Over centuries this unintentional selection produced a plant that looked, behaved, and yielded differently from its wild ancestor, with bigger seeds, easier harvesting, and less ability to survive without human help.
Map the hearths and you see this process repeated with different crops: wheat and barley in the Fertile Crescent, rice in Southeast and East Asia, millet in parts of Africa, maize and squash in Central America, potatoes in the Andes. From each hearth, farming then moved outward into new territory as expansion diffusion, carried by migrating farmers and borrowed by neighboring groups, which is how a handful of origin points eventually covered most of the inhabited world.
Key terms
- Agricultural hearth
- A region where people independently domesticated local plants or animals and began farming for the first time.
- Domestication
- The genetic change of a wild species over many generations, shaped by human harvesting, planting, or breeding.
- Selective harvesting
- Gathering and replanting only the plants with certain traits, which unintentionally shifts the traits of the next generation.
- Expansion diffusion
- The spread of an idea or practice outward from its origin into new areas while it remains strong in the original location.
- Shattering
- The trait of a wild grain's seed head breaking apart and dropping seeds before harvest, lost in domesticated crops.
Watch it explained
- How it worksHow does domestication turn a wild plant into a crop over generations of selection?
- Worked exampleShow me the Fertile Crescent, the Indus Valley, Southeast Asia, and Central America as hearths.
- Going furtherWhat happens to a wild species after thousands of years of human selection?
- Ties togetherHow does agricultural diffusion out of these hearths look as expansion diffusion on a map?
Check yourself
End of topic.