**4. China**

The main plant in this case is rice. Various types of wild and domesticated rice have a wide distribution in Asia and beyond. Domesticated rice is descended from the wild plant *Oryza rufipogon*, and at least two major types of cultivated rice, *Oryza sativa Japonica* and *Oryza sativa indica*, are currently major crops in Asia, although it is still unknown whether or not these crops are due to one or separate domestications (c.f. [21]). Many authors suggested the sites of domestication in Asia (see [22] and references there in). The best-studied and oldest rice known is from the middle Yangtze Basin from the Diaotonghuan Cave in that region [20]. The time to be assigned to the domestication of the rice is also uncertain and depends on the definition of "domestication." The presence of the double-peaked glume is a good characteristic distinguishing between domesticated and wild rice [20]. Wild rice grew in the Yangtze Basin and was harvested by local people by ~12,000 ybp, that is, before the climate emergence from the Younger Dryas. Domesticated rice is dated to 9000–10,000 ybp. If this latter date is correct, then the remains found in the Diaotonghuan Cave site were the earliest domesticated rice remains found to date. This time agrees with the termination of the YD (see [22] and references therein). As in the case of the Levant, although the wild cereal grain was clearly being utilized before the sudden end of the YD, the evidence for the domesticated counterpart seems to appear shortly after the YD ended.

### **5. MesoAmerica**

Three major crops were domesticated in the early history of agriculture in MesoAmerica: the maize, the common bean, and the squash. The cultivation of maize was widespread, and it exhibits a very large morphological and genetic diversity. Maize samples were studied from its entire pre-Columbian range, which is extending from eastern Canada to northern Chile [23]. From the genetic makeup of these samples, Matsuoka et al. [23] constructed a map showing the relation of the maize types in North and South America and concluded that all of the many types of maize were derived from a single domestication of the wild grass *Teosinte* in the highlands of Mexico about 9000 years ago. Their molecular data are consistent with the date of 6250 ybp for the oldest known fossil maize [13] and with archeological estimates that crop domestication in Mexico did not precede 10,000 ybp. There is some evidence that squash (*Cucurbita pepo*) was also domesticated in the Mexican highlands between 10,000 and 8000 ybp [24].

#### **6. Andean-Amazon region of America**

A recent study of domestication of plants in the Andean-Amazon region indicates that squash and gourds were domesticated there very early [25] and

**5**

in **Table 3**.

*Climate Stability and the Origin of Agriculture DOI: http://dx.doi.org/10.5772/intechopen.83344*

Andean-Amazonian *Cucurbita pepo*

domestication.

**Table 1.**

*Early domesticated plants.*

independently from their domestication in Mexico. *Phytoliths* recovered from two sites in southwest Ecuador have been dated to 10,100–9300 ybp [25]. As in the cases of wheat, rice, and maize, there is evidence that the wild precursors were exploited earlier. The highly cultured societies, which were present when the Europeans arrived, were strongly dependent on the cultivation of the potato in the Andean highlands. The research, which indicates that Peru was the only site of potato domestication [26], gives no reliable time estimate for the development of that crop. **Table 1** gives the cited regions, the domesticated plants, and the time known for

*Cucurbita*

**Region Domesticated plant Dates of the oldest remains** Levant Wheat (emmer and einkorn) 10,600–10,000 ybp China Rice (*Oryza sativa japonica*) 10,000–9000 ybp MesoAmerica Maize ~ 9000 ybp

> 9000–7000 ybp 10,000–9000 ybp

**Table 1** indicates that the initial domestications in the four regions took place in the same period. The development of independent agricultures in these regions must have been due to something that occurred in each of the regions at the same time, which we identify with the onset of relative stability in the climate. Climate instability can be expected to strongly inhibit agriculture since agricultural societies are dependent on a relatively few species compared to simple foraging societies. For example, six species of large prey animals have been reported in the Levant before the termination of the YD ([27] but only sheep and goats are domesticates). As far as plants are concerned, each plant, whether domestic or wild, thrives best in a specific growing environment. If the environment changes so that it becomes too far from the plant's required conditions, the crop fails. For an agricultural society, this can be catastrophic because of the limited number of plants utilized and the permanence of the settlement site. It is interesting to note that the plants domesticated differed from region to region and the climates of the four regions differed widely. This supports a hypothesis that it was not the specific values of the local climate parameters (annual rainfall or mean temperature) that were of foremost importance in the inhibition of agriculture but the stability of these parameters.

**7. Time required for establishing an agricultural society: the Levant**

that they were all established within the same 5-millennium time period.

The regions listed in **Table 1** went on to complete the establishment of the four independent agricultural societies [28] are compared in **Table 2**. Some of the main changes to be accomplished to become an established agricultural society are listed

The independence of the four agricultures is borne out by the diversity of species involved in each case as shown in column 2. Each area developed its own distinct constellation of domesticated species. The last column gives the date at which the complex agriculture-based society appears to have been well established and shows

Each of the changes indicated in **Tables 2** and **3** has its own problems, and the order in which they are accomplished may differ from place to place, but all of them must be carried out to complete the development of an agricultural way of life. In

*Climate Stability and the Origin of Agriculture DOI: http://dx.doi.org/10.5772/intechopen.83344*


**Table 1.**

*Climate Change and Agriculture*

**4. China**

**5. MesoAmerica**

wants to have control of the crop. For dating the onset of agriculture, grain has the advantage that the plant material is not easily destroyed; both wild and domesticated remains of wheat have been recovered from ancient sites in the Levant. The wild grain inadvertently goes via genetic changes required for the domestication. The estimated time required for these changes is of the order of a few centuries [19]. Hence, the climate must remain stable on time scales of a few centuries for even the

The main plant in this case is rice. Various types of wild and domesticated rice have a wide distribution in Asia and beyond. Domesticated rice is descended from the wild plant *Oryza rufipogon*, and at least two major types of cultivated rice, *Oryza sativa Japonica* and *Oryza sativa indica*, are currently major crops in Asia, although it is still unknown whether or not these crops are due to one or separate domestications (c.f. [21]). Many authors suggested the sites of domestication in Asia (see [22] and references there in). The best-studied and oldest rice known is from the middle Yangtze Basin from the Diaotonghuan Cave in that region [20]. The time to be assigned to the domestication of the rice is also uncertain and depends on the definition of "domestication." The presence of the double-peaked glume is a good characteristic distinguishing between domesticated and wild rice [20]. Wild rice grew in the Yangtze Basin and was harvested by local people by ~12,000 ybp, that is, before the climate emergence from the Younger Dryas. Domesticated rice is dated to 9000–10,000 ybp. If this latter date is correct, then the remains found in the Diaotonghuan Cave site were the earliest domesticated rice remains found to date. This time agrees with the termination of the YD (see [22] and references therein). As in the case of the Levant, although the wild cereal grain was clearly being utilized before the sudden end of the YD, the evidence for the domesticated

Three major crops were domesticated in the early history of agriculture in MesoAmerica: the maize, the common bean, and the squash. The cultivation of maize was widespread, and it exhibits a very large morphological and genetic diversity. Maize samples were studied from its entire pre-Columbian range, which is extending from eastern Canada to northern Chile [23]. From the genetic makeup of these samples, Matsuoka et al. [23] constructed a map showing the relation of the maize types in North and South America and concluded that all of the many types of maize were derived from a single domestication of the wild grass *Teosinte* in the highlands of Mexico about 9000 years ago. Their molecular data are consistent with the date of 6250 ybp for the oldest known fossil maize [13] and with archeological estimates that crop domestication in Mexico did not precede 10,000 ybp. There is some evidence that squash (*Cucurbita pepo*) was also domesticated in the Mexican

A recent study of domestication of plants in the Andean-Amazon region indicates that squash and gourds were domesticated there very early [25] and

first step in the development of an agricultural society to take place.

counterpart seems to appear shortly after the YD ended.

highlands between 10,000 and 8000 ybp [24].

**6. Andean-Amazon region of America**

**4**

*Early domesticated plants.*

independently from their domestication in Mexico. *Phytoliths* recovered from two sites in southwest Ecuador have been dated to 10,100–9300 ybp [25]. As in the cases of wheat, rice, and maize, there is evidence that the wild precursors were exploited earlier. The highly cultured societies, which were present when the Europeans arrived, were strongly dependent on the cultivation of the potato in the Andean highlands. The research, which indicates that Peru was the only site of potato domestication [26], gives no reliable time estimate for the development of that crop.

**Table 1** gives the cited regions, the domesticated plants, and the time known for domestication.

**Table 1** indicates that the initial domestications in the four regions took place in the same period. The development of independent agricultures in these regions must have been due to something that occurred in each of the regions at the same time, which we identify with the onset of relative stability in the climate. Climate instability can be expected to strongly inhibit agriculture since agricultural societies are dependent on a relatively few species compared to simple foraging societies. For example, six species of large prey animals have been reported in the Levant before the termination of the YD ([27] but only sheep and goats are domesticates). As far as plants are concerned, each plant, whether domestic or wild, thrives best in a specific growing environment. If the environment changes so that it becomes too far from the plant's required conditions, the crop fails. For an agricultural society, this can be catastrophic because of the limited number of plants utilized and the permanence of the settlement site. It is interesting to note that the plants domesticated differed from region to region and the climates of the four regions differed widely. This supports a hypothesis that it was not the specific values of the local climate parameters (annual rainfall or mean temperature) that were of foremost importance in the inhibition of agriculture but the stability of these parameters.
