ORIGIN OF AGRICULTURE

1. ORIGIN OF AGRICULTURE

2. Cultural Ages • Archeologists have divided the cultures of the past into ages based on materials used for making tools: • Stone age • Old Stone Age - Paleolithic • New Stone Age - Neolithic • Bronze Age • Iron Age

3. Tools and Technology • Obviously more science need to make a bronze tool than a stone one • Knowledge of geology to find the ore • Chemistry to form the material • So even though the terms apply to cultures there is a great deal of technology that is implied in these terms.

4. Stone Age Periods • Paleolithic Period - humans existed by foraging: • Hunting, fishing, gathering wild berries, roots, seeds, etc • Number of people restricted by food available in the area • Neolithic Period - people controlled there own food supply by cultivating plants and breeding animals

5. Major Change in Neolithic Period • Possible to feed more people than yourself • This allows for populations to increase • This leads to communities • To cities and to advanced civilization • Without agriculture advanced civilizations would not be possible

6. Neolithic Revolution • Man’s shift to food production by domesticating plants and animals was a revolutionary change in human history • Called Neolithic Revolution or Agricultural Revolution • But when, why, and how did the change occur?

7. Human species • Human species (Homo sapiens) has existed for possibly as long as 400,000 years • For most of that time, humans survived as foragers or hunter-gatherers, gathering wild plants and hunting animals

8. Shift in Human Enterprise • Around 10,000 years ago this shift from foraging to farming occurred in many areas • Arose independently in different areas of world • This formed the basis of advanced civilization in both the Old and New World • Over the centuries agriculture spread • Foragers gradually became restricted to marginal areas

9. Foraging Societies Today • Largely disappeared • Comprise only a tiny percentage of the human population • Limited to a tropical rain forests, deserts, savannahs, tundra, and boreal forests • There may be only around 250 foraging groups (many of these partly agricultural)

10. Diet of Foraging Societies • Evidence indicates they had a varied diet • They were (and are) well fed • Most groups use a lot of plants in their diet (there are some exceptions like the Eskimo who eat fish and meat). • Study of the Kung people of Africa show that hunter-gatherers have a thorough knowledge of the botany in the area.

11. Foragers are SkilledBotanists Foragers know • which plants are edible or poisonous • which are medicinal or psychoactive • which are sources of dyes • which used for weaving or building materials • remarkable methods to prepare edible foods from plants with toxins such as cassava which contains hydrocyanic acid

12. Neolithic Revolution • About 10,000 years ago archaeological evidence indicates that human cultures began the practice of agriculture in several different areas of the world • Over the next few thousand years in the Near East, the Far East and Mesoamerica agriculture flourished

13. Why did people switch to agriculture after thousands of years of foraging? • Legends among different groups • “A gift from the gods” - Egyptians, Greeks, Aztecs • Many theories focus on a wise person or brilliant sage (Genius Theory) • If you sow seeds, a plant will grow. • Dump Heap - discarded seeds at dump sites (manure good fertilizer) • Primitive burial - bury food with the dead *** Last 3 are all variations on same theme

14. New Theories • Beginning in 1960, archaeologists questions the old theories • Agricultural was a gradual cultural evolution not a revolution • Hunter-gatherers knew the wild plants, knew how they grew, and would incorporate farming along with foraging as part of an overall food collection strategy when necessary

15. People knew plants • No need to cultivate because there was abundant food for foraging • Environmental change made the difference • Lots of suggestion as to what that environmental change was • Some say last Ice Age • Some say population pressure • Whatever the cause, people began using their botanical knowledge in cultivation

16. Transitional stage between foraging and agriculture? • Foraging groups formed settlements but sent out members to hunt and gather • This permitted populations to increase • Transitional stage lasted for several thousand years in some locations until resource stress or environmental change led to the switch to agriculture.

17. Environmental Stress • In the Near East, for example, archaeologists believe that the climatic dry period around 11,000 years ago brought about a change in the distribution of cereal grains (especially wheat and barley). • Applying their botanical knowledge, these foragers gradually changed from collecting these wild cereals to cultivating them.

18. Early sites of agriculture: • Many sites of early agriculture in both the Old and New Worlds • Agriculture dates back approximately 10,000 years in Near East, Far East, and also in the New World • The oldest site in the Far East - about 11,500 yrs ago - This site most recent discovery

19. Early Sites of Agriculture

20. Near East • Some of the best studied sites of agriculture are in southwestern Asia • In foothills around the FertileCrescent • Area around the Tigris and Euphrates River is a particularly rich area for archeologists especially the foothills of Zagros Mts in Iraq and Iran

21. Near East

22. Agriculture in the Near East • Barley domesticated first - about 10,000 years ago • Two kinds of wheat • Einkorn wheat • Emmer wheat • Other crops - peas and lentils • Domesticated animals: dogs, goats, sheep

23. Far East • Several locations in Far East including China and Thailand • Yangtze and Yellow River Valleys in China are well sited sites

24. Far East

25. Agriculture in the Far East • Current studies indicate that rice cultivation began approximately 11,500 years ago along middle reaches of the Yangtze River • Predates agriculture in Near East by 1,500 years • Other crops foxtail millet (about 8000 yrs ago), broomcorn millet, rapeseed, and hemp • Animals include cattle, pigs, dogs, poultry

26. New World • Various sites in Mexico and Peru • Best studied sites in Tehuacan Valley of central Mexico • In caves in Tehuacan Valley archeologists have reconstructed lives on inhabitants over a 12,000 year period. Initially people foraged but later made transition to agriculture • Recent site is Oaxaca, south of Tehuacan

27. New World Oaxaca

28. Agriculture in New World • Impressive variety of plants but few animals • Squash domesticated about 10,000 yrs ago • Corn about 5,500 years ago • Amaranth, gourd, 3 species of bean, chili peppers, tomato, peanut, guava, sunflower, avocado, white potato, sweet potato • Animals - dogs, turkeys, llamas

29. Characteristics of Domesticated Plants • Plants that have been domesticated are genetically distinct from the wild ancestors • Domesticated plants are subject to artificialselection to suit human need rather than natural selection

30. Natural Selection • Natural selection is the process that insures that wild organisms will survive in the environment • Variation in traits occurs in a population • Those organisms that are best adapted to their environment will survive • Those that survive have offspring and pass on desirable traits to offspring

31. Artificial Selection • Once a plant is domesticated, traits are selected to suit human needs (not survival in the wild) • Some of the traits that are selected might be detrimental to survival in the wild • Corn cobs are covered with husks and have no way to disperse seeds

32. Wild and Domesticated Grains • Most wild grasses have shattering fruiting heads which break apart easily and scatter their seeds over a wide area • A recessive gene gives a tough spike with a non-shattering head • It would be natural for early foragers to gather seeds attached to tough spikes • When agriculture began these would be planted and pass on non-shattering trait

33. Other Traits • Artificial selection would result in larger seeds, or fruits, or tuber • Over time the domesticated varieties would be larger • Wild barley has two rows of grains while domesticated varieties have six rows • We continue to use artificial selection today

34. Centers of Plant Domestication • There appear to be several major centers of origin of our domesticated crops • The majority are in the Old World • Fewer are in the New World • These areas show the greatest diversity of particular crops • From here most of the major crops have spread world-wide

36. Importance of Centers of Diversity • Because these centers show the greatest diversity, the genetic variation present is important • Genes for hardiness, genes for disease resistance, genes for drought tolerance may all be present among the variation • Scientists hunt for these sources of variation