ORIGIN OF AGRICULTURE
Cultural Ages
 Archeologists have divided the cultures of
the past into ages based on materials used
for making tools:
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Stone age
• Old Stone Age - Paleolithic
• New Stone Age - Neolithic
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Bronze Age
Iron Age
Tools and Technology
 Obviously more science need to make a
bronze tool than a stone one
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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 Periods
 Paleolithic Period - humans existed by
foraging:
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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
Major Change in Neolithic
Period
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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
Neolithic Revolution
 Man’s shift to food production by
domesticating plants and animals was a
revolutionary change in human history
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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 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
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)
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.
Foragers are Skilled Botanists
Foragers know
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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
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“A gift from the gods” - Egyptians, Greeks, Aztecs
 Many theories focus on a wise person or brilliant
sage (Genius Theory)
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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 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
People knew plants
 No need to cultivate because there was
abundant food for foraging
 Environmental change made the difference
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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 Crescent
 Area 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
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Einkorn wheat
Emmer wheat
 Other crops - peas and lentils
 Domesticated 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 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
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
New World
Oaxaca
Agriculture in New World
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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
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 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
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 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
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 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
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