ORIGIN OF AGRICULTURE

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

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.

Stone Age PeriodsPaleolithic Period - humans existed by

foraging: Hunting, fishing, gathering wild berries, roots,

seeds, etc Number of people restricted by food available

in the areaNeolithic Period - people controlled there

own food supply by cultivating plants and breeding animals

Major Change in Neolithic Period Possible to feed more people than yourselfThis allows for populations to increaseThis leads to communitiesTo cities and to advanced civilizationWithout agriculture advanced civilizations

would not be possible

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?

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

Shift in Human EnterpriseAround 10,000 years ago this shift from

foraging to farming occurred in many areasArose independently in different areas of worldThis 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

Foraging Societies Today

Largely disappeared Comprise only a tiny percentage of the

human populationLimited to a tropical rain forests, deserts,

savannahs, tundra, and boreal forestsThere may be only around 250 foraging

groups (many of these partly agricultural)

Diet of Foraging SocietiesEvidence indicates they had a varied dietThey were (and are) well fedMost 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.

Foragers are Skilled Botanists

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

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

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

New TheoriesBeginning in 1960, archaeologists questions

the old theoriesAgricultural was a gradual cultural evolution

not a revolutionHunter-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

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

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.

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.

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

Early Sites of Agriculture

Near East

Some of the best studied sites of agriculture are in southwestern Asia

In foothills around the Fertile CrescentArea around the Tigris and Euphrates River

is a particularly rich area for archeologists especially the foothills of Zagros Mts in Iraq and Iran

Near East

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 lentilsDomesticated animals: dogs, goats, sheep

Far East

Several locations in Far East including China and Thailand

Yangtze and Yellow River Valleys in China are well sited sites

Far East

Agriculture in the Far EastCurrent 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

New WorldVarious sites in Mexico and PeruBest studied sites in Tehuacan Valley of

central MexicoIn 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

Oaxaca

New World

Agriculture in New World

Impressive variety of plants but few animalsSquash domesticated about 10,000 yrs agoCorn about 5,500 years agoAmaranth, gourd, 3 species of bean, chili

peppers, tomato, peanut, guava, sunflower, avocado, white potato, sweet potato

Animals - dogs, turkeys, llamas

Characteristics of Domesticated Plants

Plants that have been domesticated are genetically distinct from the wild ancestors

Domesticated plants are subject to artificial selection to suit human need rather than natural selection

Natural SelectionNatural selection is the process that insures

that wild organisms will survive in the environment

Variation in traits occurs in a populationThose organisms that are best adapted to their

environment will surviveThose that survive have offspring and pass on

desirable traits to offspring

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

Wild and Domesticated GrainsMost 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

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

Centers of Plant DomesticationThere appear to be several major centers of

origin of our domesticated cropsThe majority are in the Old WorldFewer are in the New WorldThese areas show the greatest diversity of

particular cropsFrom here most of the major crops have spread

world-wide

Importance of Centers of DiversityBecause 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