How did the spread of crops and disease along the trade networks reshape populations and environments?
Topic 2.6 Environmental Consequences of Connectivity: the diffusion of crops and agricultural practices and the spread of disease, above all the Black Death, along the trade networks.
A focused answer to AP World History Topic 2.6, explaining how the trade networks spread crops such as Champa rice and citrus, transformed agriculture and populations, and carried the Black Death across Eurasia and North Africa, killing a large share of the population.
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What this topic is asking
Topic 2.6 covers the environmental consequences of the connected world. The College Board wants you to explain two great effects of the trade networks on populations and environments: the diffusion of crops and agricultural practices, which boosted food supply and populations, and the spread of disease, above all the catastrophic Black Death.
The diffusion of crops
The first environmental consequence was the spread of crops and agricultural knowledge.
This had knock-on effects: new crops could transform local agriculture, support denser settlement, and even alter the environment through expanded farming.
The spread of disease: the Black Death
The second, and most dramatic, environmental consequence was the spread of disease.
The College Board's point is the dark side of connectivity: the very networks that carried goods, crops, and ideas also carried pathogens with terrible efficiency.
The effects were enormous:
- Demographic collapse in affected regions, with a third or more of the population dying in Europe and heavy losses across the Islamic world.
- Social and economic disruption: labor shortages, rising wages for survivors, and the weakening of established institutions, including (in Europe) the feudal and manorial order.
- A reminder that connectivity cut both ways: integration brought prosperity and catastrophe through the same channels.
Try this
Q1. Name the pandemic that spread along the trade routes in the mid-1300s and killed a large share of the population. [Recall]
- Cue. The Black Death (bubonic plague), which travelled the Mongol-secured trade routes from Central Asia across Eurasia and North Africa.
Q2. Explain one effect of the diffusion of crops along the trade networks. [Short explanation]
- Cue. New crops such as Champa rice increased food supply, supporting population growth and urbanization, as in Song China.
Exam-style practice questions
Practice questions written in the style of College Board exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
AP 2019 (style)3 marksBriefly describe ONE crop that spread along the trade networks in this period. Briefly explain ONE effect of that crop's spread. Briefly explain ONE environmental or demographic consequence of connectivity other than crops.Show worked answer →
A Short Answer Question (SAQ), 3 points, one per bullet.
A. Describe: fast-ripening Champa rice spread from Vietnam into China, and crops such as citrus, sugar, and bananas spread along the Indian Ocean and other routes.
B. Effect: new and more productive crops increased food supply, supporting population growth and urbanization, as Champa rice did in Song China.
C. Consequence: the same connectivity spread disease, above all the Black Death (bubonic plague), which travelled the trade routes and killed a large share of the population of Eurasia and North Africa.
Each bullet must be concrete. "Things spread" earns nothing; "Champa rice spread into China and boosted population" earns the point.
AP 2022 (style)6 marksEvaluate the extent to which the spread of disease was the most significant environmental consequence of connectivity in the period c. 1200 to c. 1450.Show worked answer →
A Long Essay Question (LEQ), scored on the 6-point rubric.
Thesis (1): "The spread of the Black Death was the most significant environmental consequence of connectivity, because it killed a large share of the population and reshaped societies, outweighing the slower effects of crop diffusion."
Contextualization (1): situate the period in the dense trade networks, especially those secured by the Mongols.
Evidence (2): the spread of Champa rice, citrus, and bananas and their demographic effects; the spread of the Black Death along the trade routes and its enormous death toll.
Analysis (2): explain HOW the plague's sudden mass mortality outweighed the gradual gains from crops, then add complexity by noting that crop diffusion had longer-term effects on population and that the two consequences were linked by the same networks.
Related dot points
- Topic 2.1 The Silk Roads: the causes and effects of the growth of the Silk Road trade network, including the commercial innovations and goods that flowed along it.
A focused answer to AP World History Topic 2.1, explaining how commercial innovations such as the caravanserai, money economies, and credit expanded the Silk Roads, the luxury goods and ideas that travelled them, and the diasporic merchant communities they created.
- Topic 2.2 The Mongol Empire and the Making of the Modern World: the rise and rule of the Mongol Empire and its effects on trade, technology transfer, and the connectivity of Eurasia.
A focused answer to AP World History Topic 2.2, explaining how the Mongols built the largest land empire in history, the Pax Mongolica that secured Eurasian trade, and the technology and cultural transfers their conquests accelerated across the continent.
- Topic 2.3 Exchange in the Indian Ocean: the causes and effects of the growth of Indian Ocean trade, including the technologies, goods, and diasporic communities it produced.
A focused answer to AP World History Topic 2.3, explaining how monsoon winds and maritime technologies such as the dhow, compass, and astrolabe drove Indian Ocean trade, the bulk and luxury goods it carried, the rise of the Swahili city-states, and its diasporic merchant communities.
- Topic 2.5 Cultural Consequences of Connectivity: the spread of religions, technologies, scientific and literary ideas, and the circulation of travellers across the trade networks.
A focused answer to AP World History Topic 2.5, explaining how the trade networks spread religions such as Islam and Buddhism, transferred technologies like paper and gunpowder, carried scientific and literary ideas, and circulated travellers such as Ibn Battuta and Marco Polo.
- Topic 2.7 Comparison of Economic Exchange: applying the historical reasoning skill of comparison to the causes and effects of the Silk Roads, Indian Ocean, and trans-Saharan networks.
A focused answer to AP World History Topic 2.7, the comparison reasoning skill applied to Unit 2: comparing the causes, goods, technologies, and effects of the Silk Roads, Indian Ocean, and trans-Saharan trade networks, and how to structure a comparison essay.
Sources & how we know this
- AP World History: Modern Course and Exam Description — College Board (2020)