Introduction: The Domestication of Plants and Animals: Ten Unanswered Questions

Some 15,000 to 10,000 years ago, humans started seeding and harvesting plants and maintaining animals in order to augment the food they obtained from wild-growing plants and hunting. These seemingly simple activities set in motion a long-term process that has led to the dominance of agriculture as we know it today. With the exception of a few remaining hunter–gatherer groups, agriculture has now become the most important source of food for most people. Agriculture is also a major source of feed for animals and of fiber. This transition from hunting–gathering to agriculture was without a doubt one of the most significant eras in the evolution of humans. It allowed food production on a more intensive and efficient scale than ever before, eventually leading to population increases, labor specialization (and especially a nonagricultural sector), the formation of villages, cities, and states, and the rise of more hierarchical societies and states (MacNeish 1991, Barker 2006). The late Professor J. R. Harlan (1917–1998) understood that the complexity of the biological, societal, and environmental changes involved in the transition to agriculture, as well as their antiquity of up to 10,000 years, necessitated a multidisciplinary approach if one is to understand the factors and processes that have led to the “neolithic revolution.” Anthropologists, archaeologists, climatologists, ethnobiologists, geneticists, geographers, linguists, physiologists, and other practitioners all contribute to the field of crop evolution studies. J. R. Harlan also expressed concerns that the very development and spread of improved crop varieties were leading to losses in crop biodiversity, well before concerns about biodiversity became common knowledge. He made clear how the knowledge of evolutionary processes in crops facilitated the conservation of biodiversity and its use in the development of improved crop varieties. The vision of Professor Harlan was the inspiration for the first Harlan Symposium, which took place in 1997 in Aleppo, Syria, at the International Center for Agricultural Research in the Dry Areas (ICARDA). That symposium was remarkable because it brought together plant scientists and archaeologists