Plant and Animal Domestication

The domestication of plant and animal species in prehistoric times-the so-called Neolithic Revolution- was a vital innovation and has received a great deal of scrutiny. The domestication of a species ensured its reproductive success while providing humans with some type of necessity. Domesticated organisms are usually altered in various ways due to selective breeding, making them better adapted for interactions with humans.

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Wild cereals have a very fragile stem, whereas domesticated ones have a tough stem. Under natural conditions, plants with fragile stems scatter their seed for themselves, whereas those with tough stems do not. When the grain stalks were harvested, their soft stems would shatter at the touch of a harvesting tool, and many of their seeds would be lost. Inevitably, though unintentionally, most of the seeds that people harvested would have been taken from the tough plants. Early domesticators probably also tended to select seed from plants having few husks (outer seed coverings) or none at all- eventually breeding them out- because husking prior to pounding the grains into meal or flour required extra labor. Many of the distinguishing characteristics of domesticated plants can be seen in remains from archaeological sites. Paleobotanists can often tell the fossil of a wild plant species from a domesticated one by studying the shape and size of various plant structures.

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Domestication also produced changes in the skeletal structure of some animals. The horns of wild goats and sheep differ from those of their domesticated counterparts, and some types of domesticated sheep lack horns altogether. Similarly, the size of an animal or it sparts can vary with domestication, as seen in the smaller size of certain teeth of domesticated pigs compared to those of wild ones.

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A study of age and sex ratios of animal remains at an archaeological site may indicate whether animal domestication was practiced. Investigators have determined that if the age and/or sex ratios at the site differ from those in wild herds, the imbalances are due to domestication. Archaeologists documented a sharp rise in the number of young male goats killed at 10,000-year-old sites in the Zagros Mountains of Iran. Evidently people were killing the young males for food and saving the females for breeding. Although such herd management does not prove that the goats were fully domesticated, it does indicate a step in that direction. Similarly, archaeological sites in the Andean highlands dating to around 6,300 years ago contain evidence that lamas were placed in enclosures, indicating the beginning of domestication.

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Although it is tempting to think that a sudden flash of insight about the human ability to control plants and animals might have led ancient peoples to domestication, the evidence points us in different directions. There are several false ideas about the motivation for becoming food producers. First, contemporary foragers (people who search for food) show us that food production probably did not come about from sudden, unforeseen discoveries, such as that seeds can be planted and grown into plants, since these food foragers are perfectly aware of the role of seeds in plant growth, that plants grow better under certain conditions than others, and so forth. Jared Diamond aptly describes contemporary food foragers as“walking encyclopedias of natural history with individual names for as many as a thousand or more plant and animal species, and with detailed knowledge of those species’ biological characteristics, distribution, and potential uses.” In addition, food foragers frequently apply their knowledge to actively manage the resources on which they depend. Indigenous people living in northern Australia deliberately alter the runoff channels of creeks to flood extensive tracts of land, converting them into fields of wild grain.

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Second, the switch from food foraging to food production does not free people from hard work. In fact, available ethnographic data indicate just the opposite. They show that farmers, by and large, work far longer hours compared to most food foragers. Finally, food production is not necessarily a more secure means of subsistence than food foraging. Seed crops in particular-of the sort originally domesticated in Southwest Asia, Central America, and the Andean highlands-are highly productive but not stable because of low species diversity. Without constant human attention, their productivity suffers.

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?Wild cereals have a very fragile stem, whereas domesticated ones have a tough stem. Under natural conditions, plants with fragile stems scatter their seed for themselves, whereas those with tough stems do not. When the grain stalks were harvested, their soft stems would?shatter?at the touch of a harvesting tool, and many of their seeds would be lost. Inevitably, though unintentionally, most of the seeds that people harvested would have been taken from the tough plants. Early domesticators probably also tended to select seed from plants having few husks (outer seed coverings) or none at all- eventually breeding them out- because husking prior to pounding the grains into meal or flour required extra labor. Many of the distinguishing characteristics of domesticated plants can be seen in remains from archaeological sites. Paleobotanists can often tell the fossil of a wild plant species from a domesticated one by studying the shape and size of various plant structures.

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