Conclusion

Domesticated plants feed most of the earth’s population today. Methodological advances in archaeology and increased interest in the origins of domestication and agriculture have led to a degree of consensus on the ‘what’, ‘where’, and ‘when’ of these processes. There are three thresholds of domestication and agriculture within the primary centers. First, in the Early Holocene there were frequent and dispersed plant domestications; some were advantageous and left traces in the archaeological record. First domesticates included food plants - mostly annuals grown for their nutritious seeds and starch-rich roots, tubers, or stems propagated by cuttings - as well as useful species like gourd (floats, containers). Long-lived fruit and nut trees were managed, but slower to undergo genetic change. In two centers, Eastern North America (United States) and sub-Saharan Africa, this first threshold dates to the mid-Holocene.

Second, early domesticates spread, sometimes widely, through social interactions among forager/ horticulturists. Cultivation was small-scale in well-watered settings, use of wild and managed species continued, and local species were sometimes domesticated. These developments initially had little effect on societies.

Third, increasingly productive crops fueled population growth within communities, which led to the spread of societies dependent on agriculture into new habitats, and creation of built environments for farming. Interactions between expanding farming populations and local foragers were likely complex, and remain poorly understood. The third threshold is the most visible of the process, having left its mark on the landscape in the form of irrigation and drainage canals, planting terraces and mounds, or plowing scars; in sedimentary records in the form of evidence for deforestation and erosion; and in sheer numbers of Neolithic/Formative archaeological sites. There is considerable variation in the time lapse between first domestications and dependence on agriculture -1000-6000 years - for reasons likely rooted in historical circumstances and differences in environments and crops.

There is less consensus on the ‘why’ of domestication and agriculture, except for a fundamental understanding that these are separate phenomena, best understood as processes, not revolutions. Many would agree that domestication grew out of normal foraging behaviors in the changing conditions of the early Holocene: behaviors that were mutually beneficial to foragers and plants, or that optimized caloric return for energy expended by foragers. Some would argue that an external ‘push’ was required to start the process: deteriorating climate or increasing populations. Others emphasize the role of social factors and individual decision-making in the emergence of agriculture: gaining prestige by producing surplus food for feasting. The future holds great potential for testing these and other ideas about why humans domesticated plants and became agriculturalists, and for filling in gaps in our knowledge of understudied crops and regions.

See also: Africa, Central: Foragers, Farmers, and Metallurgists; Africa, North: Sahara, Eastern; Agricultural Fields, Identification and Study; Agriculture:

Biological Impact on Populations; Social Consequences; Americas, Caribbean: The Greater Antilles and Bahamas; The Lesser Antilles; Americas, Central: Early Cultures of Middle America; Lower Central America; Americas, North: Eastern Woodlands; Plains; Americas, South: Amazon Basin; Early Cultures of the Central Andes; Northern South America; Southern Cone; Animal Domestication; Asia, East: China, Neolithic Cultures; Japanese Archipelago, Paleolithic Cultures; Japanese Archipelago, Prehistoric Hunter-Fisher-Gatherers; Asia, South: Ganges Valley; Indus Civilization; Neolithic Cultures; Chemical Analysis Techniques; Coprolite Analysis; DNA: Ancient; Modern, and Archaeology; Europe: Neolithic; Europe, Northern and Western: Early Neolithic Cultures; Mesolithic Cultures; Health, Healing, and Disease; Interdisciplinary Research; Migrations: Pacific; Oceania: New Guinea and Melanesia; Paleoenvironmental Reconstruction in the Lowland Neotropics; Paleoethnobotany; Phytolith Analysis; Pollen Analysis; Starch Grain Analysis; Trace Element Analysis.