The alternative scenario suggests that man had to reach a certain level of social organization or tool-making development, with a settled mode of life, before agriculture was possible, and this stage of human development was only reached 9 - 10 years ago. The move from shifting agriculture to domesticated agriculture was preceded and made possible by the millennia of accumulated experience of wild plants and animals, and trial-and-error experimentation.
There was probably a gradual shift from collecting to cultivation with continued reliance on hunting and gathering. Finally there was almost complete reliance on agriculture as the major source of nutrition.
In some areas of the world, primitive methods are still the most effective. Photographs Courtesy of Dr. The stages of harvesting, planting and storing imposed various artificial selection pressures such as the following:.
Over time, these selection pressures produced changes in the crop and seeds that are characteristic of domesticated crops. These changes referred to as domestication markers are most pronounced when comparisons are made between the domesticated crop and its wild relatives. Typical domestication characteristics exhibited by modern varieties of maize left and Wheat right. Galton - identified behavioural and physiologic characteristics of animals which would make them better candidates for domestication i.
Goats exhibit more pre-adaptations to domestication than pigs. List 5 advantages and 5 disadvantages to a community that may arise when communities become sedentary. Can you find out using the internet the percentage of UK households that grow any of their own food? The world was formed ca 4, million years ago.
Eukaryotic life forms: ca. First hominid life forms 4 million years ago hunter gatherers. First human farmers: about 12, years ago. Global Agricultural Evolution: — AD. Modern Agricultural Evolution: - present.
This region kick-started the Neolithic Revolution. Dates for the domestication of these animals range from between 13, to 10, years ago. Genetic studies show that goats and other livestock accompanied the westward spread of agriculture into Europe, helping to revolutionize Stone Age society.
While the extent to which farmers themselves migrated west remains a subject of debate, the dramatic impact of dairy farming on Europeans is clearly stamped in their DNA. Prior to the arrival of domestic cattle in Europe, prehistoric populations weren't able to stomach raw cow milk.
But at some point during the spread of farming into southeastern Europe, a mutation occurred for lactose tolerance that increased in frequency through natural selection thanks to the nourishing benefits of milk. Judging from the prevalence of the milk-drinking gene in Europeans today — as high as 90 percent in populations of northern countries such as Sweden — the vast majority are descended from cow herders.
Photograph by Robert Madden. Fertile Crescent. Near East. Stone Age. Media Credits The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit.
Media If a media asset is downloadable, a download button appears in the corner of the media viewer. Text Text on this page is printable and can be used according to our Terms of Service.
Interactives Any interactives on this page can only be played while you are visiting our website. Related Resources. Agricultural Communities. View Collection. The first tractors were steam-powered engines designed to haul agricultural equipment and were too expensive for most farmers. The gasoline-powered tractor was invented in The last century has seen a host of changes in the way farming is carried out and in the way farm produce shows up on our tables.
In , a trucking executive complained during a round of golf about how the summer heat was spoiling much of the food shipped by his company. His companion, Joseph Numero, jokingly suggested refrigerating the trailers. The idea stuck, and Numero went on to start a refrigerated transport company with the help of inventor Frederick Jones. Meanwhile, the development of hybrid seed , and particularly hybrid corn, revolutionized agriculture.
Hybrids improve the results of planting, and often produce plants and fruits that are hardier and more uniform. Hybrid seeds contributed to the increased agricultural output of the second half of the 20th century. Despite these great improvements, other changes arrived with controversy. During the past 10 years, a huge controversy has raged over the use of chemical pesticides and fertilizers on farms as well as genetically modified organisms. Growing awareness of how chemicals impact human health and the environment has led to calls for increased government regulation of the agricultural industry.
Throughout history, increases in agricultural productivity competed against population growth, resource degradation, droughts, changing climates, and other forces that periodically crippled food supplies, with the poor bearing the brunt of famine.
Like many of their modern counterparts, early farmers often worked land in ways that depleted its fertility. Technological innovations like irrigation circa BCE and the plow circa BCE brought enormous gains in productivity, but when used irresponsibly they degraded soil—the very foundation that makes agriculture possible.
By , economist Thomas Malthus warned that unchecked population growth would outpace food production, setting the stage for widespread starvation. In , economist Thomas Malthus warned that unchecked population growth would outpace food production, setting the stage for widespread starvation. Application of anhydrous ammonia synthetic nitrogen fertilizer at planting time on an Iowa farm.
Synthetic fertilizers are manufactured using a technique that transforms nitrogen in the atmosphere into a form that can be applied to crops ammonia.
These chemicals have dramatically increased short-term crop yields, though not without consequences. The heavy use of synthetic fertilizers has become a hallmark of industrial agriculture. Freight train carrying grain across Washington state. Beyond synthetic fertilizers, other innovations in food production and distribution helped food supplies keep pace with population growth.
Expanded railways, shipping canals, and new machinery for storing and moving grain made it easier to transport food to where it was most needed. From to , the global population grew from 1. Still, the sheer volume of production dwarfs that of earlier generations.
What has made such unprecedented abundance possible? Innovations in food production and distribution have thus far helped food supplies keep pace with population growth. Crops indigenous to the Americas, such as corn, sweet potatoes, and cassava, spread across the globe.
The nutrients provided by these prolific crops helped prevent malnutrition, supporting a widespread increase in population over the 18 th century. Of all the innovations in agriculture, arguably none has been more influential than synthetic fertilizers—chemicals manufactured using a technique that transforms nitrogen in the atmosphere into a form that can be applied to crops ammonia.
The following list of suggested resources is intended as a starting point for further exploration, and is not in any way comprehensive. Montgomery D. Dirt: The Erosion of Civilizations. Boston, MA: Houghton Mifflin; Kremer M.
Q J Econ. Trinkaus E. Early Modern Humans. Annu Rev Anthropol.
0コメント