In China rice and millet were domesticated by 7500 BC, followed by the beans mung, soy and aduki. In the Sahel region of Africa local rice and sorghum were domestic by 5000 BC. Local crops were domesticated independently in West Africa and possibly in New Guinea and Ethiopia. Three regions of the Americas independently domesticated corn, squashes, potato and sunflowers.

Humans in many different areas of the earth took up farming in what is, set against the 500,000 year age span of modern humans, a very short time. This is the most convincing evidence that global climate change, and the resultant adaptations by vegetation, were the cause of the beginning of agriculture.


Hunter gatherers
We are wrong if we assume that the change from hunter gathering to farming bought an improvement in the quality of the human life or in the humans themselves. Skeletal evidence reveals that hunter gatherers were in fact, taller, better nourished, suffered less disease and lived longer than farmers. The gathering of wild grains produces more calories of food for each calorie of energy invested than any form of agriculture

. Hunter-gatherers typically get more of their energy from gathering plant sources, usually done by women, than from hunting. Their diet is extremely diverse and thereby balanced, between 3000 and 5000 plants were gathered as food in North America. Hunter gathering humans had developed superior stone tool making skills, bone needles and fish-hooks, jewellery, art and music over 30,000 years prior to the advent of agriculture. We have discovered from the last remaining hunter-gatherer societies that these people have an encyclopaedic knowledge of plants and their uses and names for every species.

No hunter gatherer would voluntarily change to farming. The practice of cultivation developed gradually in settled communities over thousands of years. Migrant mothers have to carry around their children and generally have longer birth intervals and lower birth rates than settled people. Increased population required increased food enforcing more reliance on agriculture.
Settled agriculturists can survive at higher population densities estimated to be 10-100 times greater than hunter-gatherers.

Animals
As well as the best available domesticable plants the Eurasian continental block was also the home of the major domestic farm animals. Sheep, goats and pigs were domesticated along with the first plants and surely attributed to the rise of the agriculturists. Around 6000 BC cows were domesticated and began taking on the burden of farm labour.
However crop domestications took place in the Americas and New Guinea in the absence of any domesticable large mammals. When humans had first arrived on the these continents (Australia c.35,000 BC, Americas c.11,000 BC) they had quickly hunted into extinction these continent's native large mammals. Having not co-evolved with proto-humans these animals presumably lacked fear. At the time of the beginning of agriculture burgeoning numbers of highly skilled human hunters aided by dogs ( domesticated c.10,000 BC) caused serious depletion of wild game animals. In West Asia huge herds of gazelles had been decimated despite the fact that these animals can run at 50 miles per hour and jump up to 30 feet. This factor may have contributed to increasing demands on plant food sources and been an incentive to cultivate.

How did humans domesticate plants?
The mutation, which marks the beginning of domesticated crops, was the loss of wild mechanisms in grasses and legumes for the scattering of seeds. Humans selected for grains whose stalks had failed to shatter and legumes whose pods failed to explode. Simply by cultivating the seed which was easiest to collect humans unintentionally caused a genetic change in plants. The resultant plants, lacking any means of seed dispersal, could not have survived without human intervention.

Annual plants had evolved ways to spread the germination of their seeds over several years in order to survive particularly bad weather. Seeds which sprouted immediately would have been the ones which were collected and then sown by the first farmers. Thus agricultural practice led to the loss of dormant seeds. Sowing and harvesting in bulk on the same occasion selected for plants that grew at more uniform rates.

Farmers also selected for noticeable qualities such as size and taste. Different plants were selected for differing features such as bigger seeds, bigger fruits or oilier seeds. Plants which put more energy into the production of one part usually do so at the expense of another; squashes selected for larger fruit developed smaller leaves. Some plants were selected for different characteristics such as beets already grown in Babylonian times for their leaves (chard), beets were then developed for their edible roots and eventually in the 18th century for their sugar content. Corn, now one of the world's staple crops, may owe it's domestication to it's use in ritual and not as a food. Teosinte the probable ancestor of corn has a tiny seed enclosed in a hard coating. Farmers in Central America bred hundreds of distinct varieties of varied colours for differing purposes. Archaeologists debate how many 100's or 1000's of years corn cobs took to reach thumb size. Olives, flax, safflower, oil palm and rapeseed were selected for oil content. Hemp, fax and cotton were selected for their use as fibre. Domesticated their stimulants qualities were tobacco in North America, coca and mate in South America, coffee in Ethiopia and tea, ginseng and camphor in China. Some plants which produced poisonous compounds were domesticated from mutant individuals which lacked the poison. Wild relatives of almonds, potatoes, aubegines, watermelons, cabbages and lima beans were all too bitter or poisonous for human consumption

Around 4000 BC the domestication of fruit and nut trees was made possible. These had resisted domestication because seed selected from desirable plants could not be relied upon to reproduce similarly desirable offspring. The discovery of propagation of cuttings overcame this problem in olives, figs, grapes and pomegranates. Apples, pears, plums and cherries had to await the development of grafting skills which originated in China.

A change in the reproductive biology of cultivated plums, peaches, apricots, apples, grapes and cherries occurred when humans selected and bred mutant plants.. These plants became self-compatible hermaphrodites which could pollinate themselves. These plants could be relied upon to produce some progeny with the same characteristics of the parent making them more useful to ancient farmers.

. The last major group of plants to be domesticated were plants that had began as weeds within fields of cultivated crops. These plants had adapted to the conditions of agriculture without cultivation by humans. These include rye, oats, turnips, beets, leeks and lettuce. . The collection and planting of seed in each village led to plants becoming adapted to localised growing conditions. Eventually this led to the creation of thousands of distinct varieties of staple food crops.
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How did plants domesticate humans?
From the cultivated plant's point of view, the active assistance of humans was affording them a competitive advantage. The plants responded by evolving traits that increased their suitability for human cultivation. Plants have evolved many strategies to use animals to disperse their seed more efficiently than wind or water. The seeds of many wild species of plants must pass through an animal's gut before they can germinate. Some plants are reliant on just one species of animal to disperse their seed.

The evolutionary changes of plants constantly interact with evolutionary changes in animals in a process of co-evolution. An example is 100 million years ago when there was a rapid co-evolution of insect species and flowering plants; the new flowering plants proliferated displacing the fern and conifer dominated flora. Herbivorous dinosaurs then evolved shorter necks to feed off vegetation that was closer to the ground

By 6000 BC some societies were almost completely dependent on domesticated crops and animals. As agriculture produced more food than was necessary for subsistence it has been theorised that the practice of agriculture encouraged the division of labour, specialisation and the beginnings of a political elite. The concentration of stored food was a resource that could be seized and controlled by an elite, armies could be fed on the food grown by others thus giving power to Chieftains to engage in wars of conquest.

The lack of varied chromosomal arrangements in the founder crops of the Fertile Crescent indicates that they derive from a single domestication process. Stone Age farming communities quickly spread across Europe and the Indian subcontinent. They brought with them their seeds, introducing their crops to regions where their wild ancestors could not have survived. The vast East-West expanse of the Eurasian continent assisted rapid movement of a package of crops adapted to the similar growing seasons of the same latitudes.

By the time of Christ the crops of the fertile crescent crops grew over the 10,000 miles from Ireland to Japan. When European invaders arrived in what they termed the "new world" they adopted some indigenous crops such as Andean potatoes and New Guinean sugarcane. Where entire agricultural cultures were destroyed, such as the area currently the Eastern United States, locally domesticated crops were abandoned. Some of these crops which have remained obscure internationally offer great potential as food crops, such as Andean quinoa which is now becoming wider known.

The original farmers who were still highly reliant on gathered food, utilised their knowledge of wild plants to discover all the plants whose cultivation offered greatest potential. This is borne out by the fact that they domesticated all the staple modern food crops. Diversity which took thousands of years to develop has been whittled away in less than a century. The legacy of crop diversity created by these ancient breeders is the basis of the security of the food supply to this day.

***Please note this only one history of agriculture based on a western perspective.***