Lesson 1.6 · Period 1 · CED topic 1.7
Thinking about causation: the effects of the voyages
Every Period closes with a skills topic, and Period 1's is causation. Learning Objective G asks you to explain the effects of the development of transatlantic voyages from 1491 to 1607. This lesson is a practice session: it shows how historians separate causes from effects, how to rank them, and how to turn them into a thesis and a body paragraph. Use it as a template for every period.
Learning objective.
- 1G. Explain the effects of the development of transatlantic voyages from 1491 to 1607.
Reasoning process. Causation. The exam asks you to apply it to the developments of the whole period, so this lesson practices it on the period's central evidence.
What causation reasoning asks of you
The CED defines causation as five related moves:
- Describe causes and effects of a development.
- Explain the relationship between causes and effects, saying how one led to the other.
- Distinguish primary from secondary causes and short-term from long-term effects.
- Explain how context influenced the development.
- Judge relative significance: which causes or effects mattered most, and why.
A primary cause is the main reason something happened; a secondary cause contributed. A short-term effect appears within a few years; a long-term effect lasts decades or centuries. "Because" is a weak connector unless you say what changed and how.
Applying it: the effects of the voyages
Here is the period's evidence arranged by effect and time.
| Effect | Short term (to about 1550) | Long term (after 1550) |
|---|---|---|
| Biological | Epidemics kill large shares of Native populations | Lasting demographic loss, new crops feed Old World populations |
| Economic | Spanish conquest, silver flows to Europe | Price rises, shift from feudalism to capitalism, joint-stock companies |
| Labor and social | Encomienda and African slavery spread | Racial hierarchies and the Atlantic slave trade |
| Political | Spanish empire in the Americas | Rivalry among European powers and colonies by England, France, and the Dutch |
| Cultural | Missions and cultural blending | Debates over Native rights and racial ideas |
Notice that the effects fall on three continents. Africa gained and lost: some African states grew richer by trading captives, while millions were taken from their homes. The Americas suffered the greatest short-term damage. Europe gained wealth, crops, and new rivalries.
Ranking significance
To compare, ask what would have been different without each effect. Without the epidemics, Spain would have had much more difficulty conquering the Aztec and Inca; without American silver, Europe's economy would have grown more slowly; without the slave trade, plantation colonies would have lacked their major labor source. Many historians would name the demographic catastrophe the most significant effect because it shaped all the others: it opened the land to settlers, destroyed Native political systems, and created the demand for enslaved labor. Another argument could rank the slave trade first because of its long-term legacy. Either answer earns credit if you support it with evidence and reasoning.
Prompt. Evaluate the effects of European transatlantic voyages on the Americas and Europe from 1491 to 1607.
Thesis (a line of reasoning, not a list). European voyages drastically reduced Native populations and created forced-labor economies in the Americas, while enriching European states and merchants and reshaping Europe's economy.
Body paragraph. The most immediate effect in the Americas was demographic. Smallpox and other Old World diseases killed a large share of Native people within decades, which weakened societies such as the Aztec and Inca and made conquest possible. The collapse also created a labor shortage, and the Spanish responded with encomienda and then African slavery, linking the Americas and Africa in an Atlantic trade that lasted for centuries. In Europe, American silver and crops financed Spanish power, raised prices, and fed larger populations. Thus a single process, the voyages, caused sharply different results, devastation in the Americas and growth in Europe, which is why historians describe the exchange as unequal.
Why it scores. The paragraph links cause and effect with "weakened...made possible" and "created a shortage...responded with," names specific evidence, and compares effects across regions.
Description of: estimates of the Native population of central Mexico, from scholarly demographic studies.
Scholars estimate that central Mexico had millions of people in 1519 and that its Native population fell to perhaps one to two million by the early 1600s. Estimates differ widely: some historians argue for a much larger starting population and a larger decline, while others offer lower numbers.
Sourcing (HIPP). These are modern scholarly reconstructions based on tribute lists, church records, and archaeology, not counts from the time. They are useful for the scale of the change but uncertain in detail, so a careful historian writes "estimates suggest" and explains the debate instead of quoting one number as fact.
Claim. Disease was a major cause of the Native population decline.
Evidence. Even the lowest scholarly estimates show a sharp fall in central Mexico after 1519, and the decline began during and after the epidemics recorded in Spanish and Native sources.
Reasoning. Because the numbers are reconstructed, the strongest statement is about the direction and scale of change, not the exact total. Pairing the numbers with eyewitness accounts such as the Florentine Codex makes the claim stronger.
Causation questions on the multiple-choice section often ask for a cause or an effect of a development in the stimulus. Read the question stem twice to see which direction it asks. On the LEQ, a thesis such as "There were many effects" earns nothing; name the effects and rank or connect them. If a prompt says "evaluate the extent," state how large the change was and why, and qualify it ("most severe in the Caribbean and central Mexico, less so in the far north").
- Distinguish a short-term effect from a long-term effect of the Columbian Exchange.
Show answer
Short term: epidemics killing large parts of Native populations. Long term: the lasting shift of Europe from feudalism to capitalism, new crop-based population growth, and Atlantic trade systems.
- Explain how the decline of Native populations led to the growth of African slavery.
Show answer
Population loss reduced the available Native labor force, and colonists and officials turned to enslaved Africans supplied by traders to staff plantations and mines.
- Which effect would you rank as most significant for the Americas, and why? Give a reasoned answer.
Show answer
A strong answer might choose demographic collapse because it made conquest possible and created labor shortages, or the slave trade because of its long-term legacy. Credit goes to the evidence and reasoning, not the choice.
- Write a thesis (one sentence) for "Evaluate the effects of Spanish exploration and conquest from 1491 to 1607."
Show answer
Spanish exploration and conquest devastated Native societies through disease and forced labor while generating silver that financed the Spanish crown and reshaped European and global economies.
- Why is "disease killed many people" not enough to earn the causation point?
Show answer
It describes a cause but does not explain the relationship: how the disease weakened societies, how that helped conquest, or what it did to labor systems.
- What makes estimates of Native population loss an uncertain kind of evidence?
Show answer
They are modern reconstructions from limited records such as tribute lists, church records, and archaeology, so numbers differ widely though they agree on the overall scale of decline.