Breakthroughs to Agriculture

The Agricultural Revolution, or Neolithic Revolution, began approximately $12,000$ years ago, marking a transition from gathering and hunting to the deliberate cultivation of plants and taming of animals.
This shift provided the foundation for growing populations, settled villages, cities, states, empires, and writing.
Domestication involves humans actively changing nature for their benefit, such as transforming corn from a $1$ -inch cob to a $6$ -inch cob by $1500$ , and selective breeding of animals for wool, milk, or eggs.
A core concept of this era is intensification, which refers to producing far more food and resources from a much smaller area of land than was possible with Paleolithic technology.

The revolution coincided with the end of the last Ice Age, a global warming process that began $16,000$ years ago and concluded around $11,000$ years ago.
Climate change led to the extinction of some large mammals and the flourishing of wild cereal grasses, creating pressure and opportunity for new food sources.
Gathering and hunting peoples developed "broad-spectrum diets" and specialized tools, including sickles, baskets, mortars, pestles, and storage pits, which served as unintentional preparation for agriculture.
Women were likely the innovators of deliberate farming due to their long association with collecting wild plants, while men likely led animal domestication.
Sedentary lifestyles in resource-rich areas led to population growth, creating a "food crisis" that motivated agricultural experimentation.

Agriculture emerged independently in scattered locations, including the Fertile Crescent, sub-Saharan Africa, China, New Guinea, Mesoamerica, the Andes, and eastern North America between $4,000$ and $12,000$ years ago.
Out of $200,000$ plant species, only several hundred have been domesticated; five crops—wheat, corn, rice, barley, and sorghum—now provide more than half of human caloric intake.
Only $14$ species of large mammals have been successfully domesticated, with sheep, pigs, goats, cattle, and horses being the most critical.
In the Fertile Crescent (Southwest Asia), a rapid transition occurred within $500$ years, starting with figs in $9,400$ B.C.E., followed by wheat, barley, sheep, and cattle.
Sub-Saharan Africa saw scattered domestication of sorghum in the eastern Sahara, teff in the Ethiopian highlands, and yams, oil palms, and okra in West Africa.
The Americas lacked most large animals for domestication, possessing only the llama and alpaca in the Andes, which meant agriculturalists there lacked animal power for plows, manure for fertilizer, and major protein sources compared to Afro-Eurasia.
Maize (corn) was domesticated in southern Mexico by $4,000$ to $3,000$ B.C.E. through thousands of years of selective adaptation from mountain grass.

The spread of agricultural innovations was influenced by geographic axes; the East-West axis of Eurasia allowed crops to spread rapidly through similar climatic zones.
The North-South axis of the Americas required agricultural practices to adapt to vastly different climatic and vegetation zones, slowing the spread of crops like corn, beans, and squash.
In the Americas, certain domesticates like the llama, potato, and quinoa never reached Mesoamerica from their Andean origins.