The Enigma of Agricultural Development and Early Explanations

Key Insight

Agriculture arose independently in some regions much earlier than in others, or not at all in areas seemingly suitable, such as California, Europe, temperate Australia, and subequatorial Africa. Initial explanations proposed either cultural deficiencies in local populations or a lack of suitable wild plants and animals. Assessing mammalian domestication is simpler, as only about 148 species of large wild terrestrial herbivores or omnivores exist, making it straightforward to determine if suitable candidates were available or if peoples' characteristics were the limiting factor.

Conversely, evaluating plants is significantly more complex due to the sheer diversity of wild flowering plants, numbering around 200000 species, which provide almost all modern crops. It is impractical to examine all wild plant species even in a localized area like California to assess their domesticable potential. This disparity in the number of potential candidates makes the role of available wild species a much harder question to answer for plants than for mammals.

However, the vast majority of wild plants are unsuitable for domestication because they are woody, produce no edible fruit, or have inedible leaves and roots. Only a few thousand of the 200000 wild plant species are consumed by humans, and just a few hundred have been domesticated, most of which are minor dietary supplements. A mere twelve species, including wheat, corn, rice, barley, sorghum, soybean, potato, manioc, sweet potato, sugarcane, sugar beet, and banana, now account for over 80 percent of the world's annual crop tonnage. The lack of new major food plant domestications in modern times suggests ancient peoples likely exploited nearly all useful wild plants.