Several plant species, the "pioneer crops" or Neolithic founder crops, were identified by Daniel Zohary, who highlighted the importance of the three cereals, and suggested that domestication of flax, peas, chickpeas, bitter vetch and lentils came a little later. Based on analysis of the genes of domesticated plants, he preferred theories of a single, or at most a very small number of domestication events for each taxon that spread in an arc from the Levantine corridor around the Fertile Crescent and later into Europe. Gordon Hillman and Stuart Davies carried out experiments with wild wheat varieties to show that the process of domestication would have occurred over a relatively short period of between 20 and 200 years. Some of these pioneering attempts failed at first and crops were abandoned, sometimes to be taken up again and successfully domesticated thousands of years later: rye, tried and abandoned in Neolithic Anatolia, made its way to Europe as weed seeds and was successfully domesticated in Europe, thousands of years after the earliest agriculture. Wild lentils presented a different problem: most of the wild seeds do not germinate in the first year; the first evidence of lentil domestication, breaking dormancy in their first year, was found in the early Neolithic at Jerf el Ahmar (in modern Syria), and quickly spread south to the Netiv HaGdud site in the Jordan Valley. This process of domestication allowed the founder crops to adapt and eventually become larger, more easily harvested, more dependable[clarification in storage and more useful to the human population.
Throughout the Paleolithic era, humans developed sophisticated technologies and adapted to different geographical environments as they migrated from Africa to Eurasia, Australasia, and the Americas.