Agriculture

Gulf Stream carries warm water from Gulf of Mexico to Atlantic Ocean

Gulf Stream travels north along eastern coast of North America

Gulf Stream moves east toward Europe

Currents flow from temperate zone toward Equator

Currents carry colder water in that direction

Tropical monsoon climate: heavy summer rains, dry winters

Tropical wet and dry climate: distinct rainy seasons, less precipitation than monsoon climate

Three basic types of temperate climates:

• Humid temperate climates:

  • Found on eastern sides of continents

  • Colder winters

  • Year-round precipitation

• Marine west coast climate:

  • Found on west coast of continents at higher latitudes

  • Cooler winters

  • Plentiful rain

  • Supports growth of temperate rain forests

• Mediterranean climates:

  • Found on west coasts of continents near deserts and around the Mediterranean Sea

  • Countries such as Italy, Greece, and Tunisia

The temperate zones have long growing seasons and are major grain-producing regions.

Wheat is a hardy grain that thrives in shorter growing seasons and drier conditions, growing well in the northern temperate zones.

Corn requires a higher average temperature to germinate than wheat and generally grows farther south.

Rice needs an even longer growing season and grows in the southernmost parts of the temperate zone, near the tropics.

Rice requires more water than wheat and corn and is grown in the warm, wet southern portion of the Mississippi.

Humid tropical and subtropical climates are well suited for wet-rice farming.

Rice growing in some areas, like California, requires irrigation.

Physical geography plays a significant role in determining agricultural practices.

Land with nutrient-poor soil, like in rainforests or semiarid grasslands, requires extensive agricultural practices.

Extensive practices involve working on a larger expanse of land to compensate for low yields.

Rich soils, like those in eastern China and the American Midwest, are suitable for intensive agricultural practices.

Intensive practices focus on smaller areas but can produce high yields.

Livestock ranching is mostly found in the western states of the United States.

Western states offer large, open tracts of land for livestock to roam and graze.

The arid grasslands in this region are suitable for extensive agriculture.

The price of marginal land in these areas is low.

Ranchers take advantage of low land costs and the availability of federal lands.

Less labor and capital are required to prepare the land for grazing.

Ranching is typically carried out in sparsely populated areas away from markets or city centers.

Ranchers must transport their livestock to markets for sale.

Between 12,000 and 11,000 years ago, Earth experienced increased warming.

The melting of massive glaciers in the Northern Hemisphere led to rising sea levels.

Climate regions underwent significant changes, with temperate regions experiencing more extreme changes than the tropics.

Around 11,000 years ago, Southwest Asia experienced a significant drop in average rainfall for an extended period, possibly lasting 1,000 years.

In response to the environmental stress, people in Southwest Asia began domesticating animals and plants to ensure a steady food supply, becoming the first humans to do so.

People migrated to and settled in warmer environments with more available food for foraging.

Population growth increased pressure on the environment, leading to scarcity of wild foods.

Cultivation of a stable surplus became necessary to meet the food demands.

Hearth of domestication: Southwest Asia (Fertile Crescent)

Crops grown: wheat, barley, rye, legumes

Domesticated animals: sheep, goats, cattle, pigs

Southeast Asia:

• Domestication began around 7000 b.c.e.

• People raised pigs and grew sugarcane and root vegetables.

Ancient North Central China:

• Two distinct hearths developed between 8000 and 7000 b.c.e.

• Northern hearth: grew millets, hemp, Chinese cabbage, and wheat.

• Southern hearth: grew rice.

South Asia (Indus River Valley):

• Harappan civilization thrived from 2500 to 1700 b.c.e.

• Cultivated wheat, barley, peas, sesame, and possibly cotton.

• Domesticated animals: cattle, fowl, pigs, camels, and buffalo.

Northern Central America and southern Mexico:

• Agricultural hearth began around 8000 b.c.e.

• Grew sweet potatoes, beans, and other crops.

• Domesticated the turkey.

• Maize (corn) became the staple crop.

Andean highlands of South America:

• Agricultural hearth began around 8000 b.c.e.

• Chief crops: beans, tomatoes, and potatoes.

• Domesticated llamas, alpaca, and guinea pigs.

Africa:

• East Africa:

  • Crops like coffee, olives, peas, and sesame originated around 8000 b.c.e.

  • Sorghum likely domesticated in Ethiopia around 4000 to 3000 b.c.e.

• West Africa:

  • People raised millets and sorghum.

Scientists distinguish hearths like the Fertile Crescent as early adopters of agriculture through diffusion.

The Nile River Valley adopted farming and animal raising from Southwest Asia.

The people in the Nile River Valley did not develop these practices independently.

It can be challenging to determine if a region was a hearth or part of a diffusion pathway.

Rice may have been domesticated independently in the Ganges River Valley or introduced from China.