Origins of agriculture (Lecture 1 and 2)

Origins of Agriculture (Lecture 1 and 2)

• Hunter-gatherers moved in small groups to hunt animals and gather plants
• They lived as hunter-gatherers for about 99% of human history
• The Neolithic Revolution, or First Agricultural Revolution, happened when people learned to grow their own food
• Agriculture involves planting seeds and taking care of plants until they grow
• Farming originated in primary centers like the Fertile Crescent (~10,000 years BP) and China (~9000 years BP)
• Secondary centers adopted agriculture and grew local plants
• Climate change made it hard to find wild food
• Bigger groups needed more food than hunting and gathering could provide
• Humans may have liked having big feasts, needing extra food
• Plants and humans helped each other
• Farming enabled people to settle in one place and build villages
• A food surplus allowed some people to do other jobs
• Division of labor emerged with some people making tools or building houses
• Living close to animals resulted in more diseases
• Domestication allowed people to improve plants for food
• Humans transitioned from wandering hunter-gatherers to settled farmers
• Agriculture greatly impacted human life, population, and societal organization

Hunter-Gatherer Lifestyle

• They existed in smaller groups
• Nomadic existence involved moving in search of food
• Sustenance was obtained by hunting and gathering
• Plentiful areas allowed more time for leisure activities like toolmaking and art
• Diets primarily consisted of meat and fish (65-100%) along with plants (0-35%)
• Archaeological evidence suggests their diet consisted of 2/3 animal protein and 1/3 plants, thus being healthy
• This lifestyle could be more efficient than early agriculture in resource-rich environments

Neolithic Revolution/First Agricultural Revolution

• A fundamental shift in how humans obtained food occurred
• Agriculture involved cultivating plants
• Sedentary lifestyle meant settling in one place
• Populations grew larger and more dense in fixed locations
• A slow process that was a gradual adoption and development of new practices
• The shift resulted in significant consequences

Origin of Agriculture

• Agriculture originated independently in multiple locations
• Primary centers existed like the Fertile Crescent (~10,000 years BP), China (~9000 years BP), New Guinea Highlands (9000-6000 years BP), Subsaharan Africa (5000-4000 years BP), Mesoamerica/North South America (5000-4000 years BP).
• Secondary centers adopted agriculture
• There is evidence of rye cultivation in the Fertile Crescent around 13,000 years BP
• Villages appeared later (12-10,000 years BP)

Reasons for the Switch to Agriculture

• There is no consensus on the primary cause
• The end of the Ice Age (~14,000 years BP) brought warmer, moister conditions, followed by the Younger Dryas (~12,000 years BP), contributing to food stress
• Agriculture arose in areas with abundant wild relatives of crops (Taurus & Zagros mountains)
• Humans assembled and stored food for gatherings, leading to agricultural technology
• Increasing populations required more food
• Agriculture unintentionally favored plants dependent on human assistance, creating a plant-human symbiosis

Consequences of the Neolithic Revolution

• A sedentary lifestyle and villages were developed
• Farming involved more labor than hunting and gathering
• Food surplus allowed for specialization and division of labor, and produced food more immediately
• Society became stratified
• Writing systems emerged
• Birthing frequency and number of children increased
• Population density grew
• Living close to domesticated animals increased zoonotic diseases
• Infectious diseases increased due to population density and poor sanitation (bird flu, plague, Covid-19, typhoid, etc)
• Skeletal and dental health declined
• Lifespan decreased
• Food storage became important
• Transportation and trade developed
• Movement of people, ideas, diseases, and wars increased

Plant Domestication

• Humans cultivated wild species
• Superior plants were selected
• Genetic isolation prevented cross-pollination
• Domesticated plants became genetically different
• Barley, wheat, chickpea, and lentil came from the Fertile Crescent
• Rice, Chinese millet, and soybean came from South-Eastern Asia
• Taro and sugar cane originated from the New Guinea Highlands
• Sorghum, millet, teff, and coffee came from Subsaharan Africa
• Potatoes, tomatoes, corn, beans, squash, and quinoa came from the Americas.
• Selection and genetic isolation improved crops
• Few plant species are crucial for food security
  • There are thousands of flowering plants, only around 150 are in world commerce
  • Only ~20 have major economic importance

Hunter-Gatherer Lifestyle Details

• Most of modern day hunter-gather diets consist of 65-100% meat and fish, and 0-35% plants
• The "Paleo diet" is related to hunter-gatherer eating habits
• Archaeological evidence suggests effective nutrition with 2/3 of food from animal protein and 1/3 from plants
• Hunting-gathering in plentiful areas could be more efficient than agriculture
• Time spent as hunter-gatherers allowed for leisure for art and tools

Neolithic Revolution/First Agricultural Revolution Details

• Transition in the Fertile Crescent wasn't sudden; rye fields began being cultivated around 13,000 years BP, but villages first came about 12-10,000 Y BP

Origin of Agriculture Details

• Agriculture had independent origins
  • Fertile Crescent: 10,000 y BP
  • China: 9000 y BP
  • New Guinea Highlands: 9000-6000 y BP
  • Subsaharan Africa: 5000-4000 y BP
  • Mesoamerica and N South America: 5000-4000 y BP
• Secondary centers: Areas where the idea of growing plants was imported but new local species were also domesticated alongside the adopted ones
• Stone pits for grinding in the Fertile Crescent provides archaeological evidence related to early plant processing

Reasons for the Switch to Agriculture Details

• The reasons are not fully clear; there is no scientific consensus
• Hypotheses:
  • Climate change: The end of the Ice Age (~14,000 y BP) warmed/moistened the conditions, but then cooled during the 'Younger Dryas' (~12,000 y BP)
  • The potential food stress caused by this may have caused agriculture to arise
  • Natural habitat: Agriculture developed in areas with abundant wild relatives (Taurus & Zagros mountains, Fertile Crescent)
  • Competitive feasting: Assembling large stores of food for large gatherings (potential rituals or displays of power) drove agricultural technology and early seed grinding. Goebekli Tepe provides archaeological evidence
  • Demographic: Increasingly sedentary and larger populations reached their carrying capacity, thus requiring more food

Consequences of the Neolithic Revolution Details

• Agriculture was NOT necessarily better for humans
• Consequences (with concrete examples):
  • Poorer sanitation
  • zoonotic diseases
  • Infectious diseases
  • Skeletal health/shorter lifespan
  • Increased work
  • Division of labor, stratification, and the development of script
  • Increase in birth frequency/children
  • Settlements
  • Development of transportation and trades
  • Spread of ideas, disease, and war
  • Increased population density

Plant Domestication Details

• Humans knew wild species and then deliberately cultivated them
• Crop development: Superior seeds/shoots selection and genetic isolation
• Domesticated species became genetically distinct
• List of plant domestications:
  • Fertile Crescent: barley, wheat, chickpea, pea, lentil, etc.
  • South-Eastern Asia: rice, Chinese millet, soybean, Chinese cabbage, etc.
  • New Guinea Highlands: taro, sugar cane, etc.
  • Subsaharan Africa: sorghum, millet, teff, coffee, yam, pigeon pea, cowpea, etc.
  • Americas: potatoes, tomatoes, corn, common bean, squash, quinoa.
• 275,000 flowering plants. 2,500 eaten regularly, 150/world trade, 20/major economic important