The Columbian Exchange

Copyright National Humanities Center, 2015

In what ways did the arrival of Europeans to America bring about unforeseen and unintended consequences for the people and environments of both the New World and the Old?


The Columbian Exchange — the interchange of plants, animals, disease, and technology sparked by Columbus’s voyages to the New World — marked a critical point in history. It allowed ecologies and cultures that had previously been separated by oceans to mix in new and unpredictable ways. It was an interconnected web of events with immediate and extended consequences that could neither be predicted nor controlled.



Charles C. Mann, 1493: Uncovering the New World Columbus Created

Text Type


Text Complexity

Grade 9–10 complexity band.

For more information on text complexity see these resources from

In the Text Analysis section, Tier 2 vocabulary words are defined in pop-ups, and Tier 3 words are explained in brackets.

Click here for standards and skills for this lesson.


Common Core State Standards

  • ELA-LITERACY.RI.9-10.1 (cite evidence to analyze specifically and by inference)
  • ELA-LITERACY.RI.9-10.2 (determine a central idea and its development)

Advanced Placement US History

  • Key Concept 1.2 (IIA) (introduction of crops and animals not found in the Americas)

Teacher’s Note

In this lesson students will explore a description of the Columbian Exchange written by Charles C. Mann as part of the introduction to his book, 1493: Uncovering the New World Columbus Created. In three excerpts students will examine elements of the Exchange — an overview, a specific biological example of unintended consequences, and finally an example of unintended human costs of the Columbian Exchange. Each excerpt is accompanied by close reading questions for students to complete. The text analysis is accompanied by three interactive exercises to aid in student understanding. The first interactive allows students to explore vocabulary in context; the second encourages students to review the textual analysis; and the third explores the use of diction, simile, and appeal to authority.

This lesson focuses upon the Columbian Exchange as an interwoven process with unforeseen consequences. Charles Mann expands upon the earlier theories of Alfred W. Crosby, who explored the idea of the Columbian Exchange in 1972 (for a general essay on the Columbian Exchange written by Crosby, including suggestions for class discussions, click here). Although Mann details the effects of tobacco, the potato, corn, malaria, yellow fever, the rubber industry, and other elements of the Exchange in both the Eastern and Western hemispheres fully in 1493, this lesson focuses specifically upon some effects of the Exchange in Hispaniola. The follow-up assignment allows students to extend the effects of the Exchange into the African slave trade. The author uses Colon, the Spanish spelling for Columbus, throughout, and that spelling has been retained in the excerpts for this lesson.

This lesson is divided into two parts, both accessible below. The teacher’s guide includes a background note, the text analysis with responses to the close reading questions, access to the interactive exercises, and a follow-up assignment. The student’s version, an interactive worksheet that can be e-mailed, contains all of the above except the responses to the close reading questions, and the follow-up assignment.

Teacher’s Guide (continues below)

  • Background note
  • Text analysis and close reading questions with answer key
  • Interactive exercises
  • Follow-up assignment
Student Version (click to open)

  • Interactive PDF
  • Background note
  • Text analysis and close reading questions
  • Interactive exercises

Teacher’s Guide


Background Questions

  1. What kind of text are we dealing with?
  2. When was it written?
  3. Who wrote it?
  4. For what audience was it intended?
  5. For what purpose was it written?

When Columbus landed on the island of Hispaniola (the island including the modern countries of Haiti and the Dominican Republic) during his first voyage in 1492, he and his men did not realize the lasting effects their voyage would have on both the New World and the Old at that time and in the years to come. The Columbian Exchange is the term given to the transfer of plants, animals, disease, and technology between the Old World from which Columbus came and the New World which he found. Some exchanges were purposeful — the explorers intentionally brought animals and food — but others were accidental. In this lesson you will read about this Exchange from a description written by Charles C. Mann, a writer specializing in scientific topics. This lesson uses excerpts from a book entitled 1493: Uncovering the New World Columbus Created in which Mann describes the effects, both intended and unintended, of the Columbian Exchange. Mann wrote 1493 to explore the Columbian Exchange as a process which is still going on today.

This lesson draws from the introduction in Mann’s book. There are three excerpts, each with close reading questions. The first excerpt is a general overview of the Exchange — while it does not include all parts of the Exchange, you will see examples of how animals and plants from one part of the world replaced those in another part of the world. In excerpt two you will explore a specific example of unintended consequences of the Columbian Exchange, when settlers thought they were simply bringing in an enjoyable food, but they wound up with an invasive pest. Finally, in excerpt three you can see the devastating effects of the Columbian Exchange upon the Taino Indians, the residents of Hispaniola before Columbus arrived. In some of the excerpts you will see Columbus spelled as Colon — this is the Spanish spelling and is used by the author.

Text Analysis

Excerpt 1

Close Reading Questions

Activity: VocabularyActivity: Vocabulary
Learn definitions by exploring how words are used in context.

1. Why do you believe Columbus brought cattle, sheep or horses with him?
They were part of the European culture. They would help in farming (cattle and sheep) and communication, transportation, and war (horses). The Spanish intended to start a colony and would need the animals.

2. What would the Taino culture have been like without cattle or horses?
There would have been communication only by human messenger and fields planted by hand. There would have been no quick communication (by horse) or plowed fields or pastures (no cattle, so they were not possible or necessary) and only a few, small paths, no real roads (the only transportation was by foot).

3. What is the thesis statement of paragraph 1? How does Mann develop that thesis? Cite evidence from the text.
The thesis is “Colon and his crew did not voyage alone.” Mann develops that thesis by giving examples to prove his point, including earthworms, cockroaches, African Grasses, rats, and other animals and plants.

4. How did the introduction of cattle and sheep affect plant life on Hispaniola?
New grasses for grazing choked out native species.

5. Why is it important that alien grasses, trees, and other plants choked out native vegetation in Hispaniola?
Choking out native grasses reduced the biodiversity (the number of distinct life forms) of Hispaniola. Ecosystems that are more biodiverse (they have more distinct life forms) are more productive and are more resistant to diseases.

6. What can be the effect of introducing a new predator into an environment, such as the Indian mongoose in Hispaniola? Give an example.
It can render another species extinct, which may itself have unintended consequences. For instance, the food source for the Dominican snake may have increased in population which may have led to other effects.

7. How does Mann show that the Columbian Exchange is still ongoing?
He relates how, in 2004, the orange groves have become prey of the lime swallowtail butterflies.

8. In the second paragraph of this excerpt, Mann implies his thesis but does not actually state it. What is the implied thesis of paragraph 2? How does he imply the thesis?
Mann implies that the Columbian Exchange can have negative results. He gives examples, citing grasses that were choked out, trees that were replaced with other types of trees, and animals driven toward extinction.

In this excerpt, Mann offers an overview of the Columbian Exchange with examples.

…Colon [Columbus] and his crew did not voyage alone. They were accompanied by a menagerie of insects, plants, mammals, and microorganisms. Beginning with La Isabela [Colon’s first settlement], European expeditions brought cattle, sheep, and horses, along with crops like sugar cane (originally from New Guinea), wheat (from the Middle East), bananas (from Africa), and coffee (also from Africa). Equally important, creatures the colonists knew nothing about hitchhiked along for the ride. Earthworms, mosquitoes, and cockroaches; honeybees, dandelions, and African grasses; rats of every description — all of them poured from the hulls of Colon’s vessels and those that followed, rushing like eager tourists into lands that had never seen their like before.


Movqvites (Mosquito), “Histoire Naturelle
des Indes,” ca. 1586

Cattle and sheep ground the American vegetation between their flat teeth, preventing the regrowth of native shrubs and trees. Beneath their hooves would sprout grasses from Africa, possibly introduced from slave ship bedding; splay-leaved [with wide leaves] and dense on the ground, they choked out native vegetation. (Alien grasses could withstand grazing better than Caribbean groundcover plants because grasses grow from the base of the leaf, unlike most other species, which grows from the tip. Grazing consumes the growth zones of the latter but has little impact on those in the former.) Over the years forests of Caribbean palm, mahogany, and ceiba [the silk-cotton tree] became forest of Australian acacia [small tree of the mimosa family], Ethiopian shrubs, and the Central American logwood. Scurrying below, mongooses from India eagerly drove Dominican snakes toward extinction. The changes continue to this day. Orange groves, introduced to Hispaniola from Spain, have recently begun to fall to the depredation of lime swallowtail butterflies, a citrus pest from Southeast Asia that probably came over in 2004. Today Hispaniola has only small fragments of its original forest.

Excerpt 2

Close Reading Questions

Activity: Diction, Simile and Appeal to AuthorityActivity: Diction, Simile and Appeal to Authority
Examine three language tools Mann uses to make a complex subject easily understood.

9. According to the author and his sources, what unintended import came in to Hispaniola with plantains?
With the plantains came scale insects.

10. How does the author define scale insects?
They are small creatures with tough, waxy coats that suck the juices from plant roots and stems.

11. Define “ecological release.”
Ecological release is when an invasive species is introduced into an environment with no natural predators and subsequently the population explodes.

12. Using the example of scale insects as evidence, why are natural predators important to an ecosystem?
They help to regulate the population of a species and keep an ecosystem in balance.

13. What was the unintended effect of this import, scale insects, according to Wilson? Why did they have this effect?
The scale insects sucked juices from plants and stems. They had no natural enemies, so their populations grew greatly. The scale insects became a food source for fire ants. With a virtually unlimited food source, the fire ant population grew greatly. The fire ants invaded settlers’ homes. This proved to be dangerous to the settlers.

14. Mann begins the second paragraph in this excerpt with “So far this is informed speculation.” What effect does this admission have on our perception of Mann as an author?
It reminds the reader that Mann is approaching his topic from a scientific perspective, being careful to alert readers to what is proven and what is not. This helps to establish him as a writer we can trust.

15. What document from the 1500s seems to confirm this unintended effect?
Bartolome de Las Casas wrote of a sudden infestation of fire ants in 1518 and 1519.

16. What was the unintended effect to settlers of the introduction of plantains to Hispaniola?
Although they had plantains to eat, they also had to deal with fire ants. As a result, they abandoned their homes.

17. How does Mann combine 16th and 20th century evidence?
He uses 20th century science to explain a 16th century eye-witness account.

Here Mann gives a specific example of unintended consequences.

Natives and newcomers interacted in unexpected ways, creating biological bedlam. When Spanish colonists imported African plantains [a tropical plant that resembles a banana] in 1516, the Harvard entomologist Edward O. Wilson has proposed, they also imported scale insects, small creatures with tough, waxy coats that suck the juices from plant roots and stems. About a dozen banana-infesting scale insects are known in Africa. In Hispaniola, Wilson argued, these insects had no natural enemies. In consequence, their numbers must have exploded — a phenomenon known to science as “ecological release.” This spread of scale insects would have dismayed the island’s European banana farmers but delighted one of its native species: the tropical fire ant Solenopsis geminata. S. geminata is fond of dining on scale insects’ sugary excrement; to ensure the flow, the ants will attack anything that disturbs them. A big increase in scale insects would have led to a big increase in fire ants.

So far this is informed speculation. What happened in 1518 and 1519 is not. In those years, according to Bartolome de Las Casas, a missionary priest who lived through the incident, Spanish orange, pomegranate, and cassia plantations were destroyed “from the roots up.” Thousands of acres of orchards were “all scorched and dried out, as though flames had fallen from the sky and burned them.” The actual culprit, Wilson argued, was the sap-sucking scale insects. But what the Spaniards saw was S. geminata — “an infinite number of ants,” Las Casas reported, their stings causing “greater pains than wasps that bite and hurt men.” The hordes of ants swarmed through houses, blackening roofs “as if they had been sprayed with charcoal dust,” covering floors in such numbers that colonists could sleep only by placing the legs of their beds in bowls of water. They “could not be stopped in any way nor by any human means.”… Overwhelmed and terrified, Spaniards abandoned their homes to the insects….

Excerpt 3

Close Reading Questions

18. What is the thesis of this excerpt?
Mann asserts that “the most dramatic impact of the Columbian Exchange was on humankind itself.”

19. What evidence does Mann use to develop this thesis?
He uses Columbus’s original account, 16th century official Spanish documents, and estimates by modern historians.

20. Why did the Spanish conduct a census of the Indians on Hispaniola in 1514? What did the census find regarding the Taino population?
The Spanish conducted a census in order to count the Taino so that they could be assigned to Spanish settlers as laborers. This was part of the encomienda system, whereby a Spanish settler was given a plantation as well as the labor of all the Indians who lived on that plantation. The census-takers found that there were few Taino left, perhaps only about 26,000.

21. According to the author, what two factors caused this change in population? Which cause was the most influential?
The two causes were Spanish cruelty and the introduction of diseases by the Columbian Exchange. The most influential was the introduction of disease.

22. The third sentence in paragraph 2 of this excerpt uses a rhetorical device called asyndeton. Asyndeton is a list of items with conjunctions omitted and can be used to imply that there are more items that could be added to the list. What types of items does the author list using asyndeton? What is the effect?
The author lists diseases, both viruses and bacteria. The effect is a “piling up”, implying that more diseases were brought to Hispaniola as well, but the author may not have the space in the sentence to list them. In fact, other diseases were introduced by the Columbian Exchange, including malaria, yellow fever, whooping cough, chicken pox, the bubonic plague, and leprosy.

23. Why was the introduction of these diseases so devastating for the Taino and not the Spanish explorers?
The Taino had never been exposed to these diseases before and therefore had no natural immunity to stop or control the spread of the disease. The Spanish did have some natural immunity, since the diseases were present in Europe at that time.

24. What is the effect of Mann including the information about the first recorded epidemic, which occurred within one year of Columbus’s arrival?
He reminds the reader that the devastating effects of diseases brought by the Exchange happened almost immediately for the Taino. This conveys the seriousness of the Exchange as well as the power of the diseases in a population with no natural immunity.

Activity: ReviewActivity: Review
Review the central points of the textual analysis.
Mann explains the most “dramatic impact of the Columbian Exchange.”

From the human perspective, the most dramatic impact of the Columbian Exchange was on humankind itself. Spanish accounts suggest that Hispaniola had a large native population: Colón, for instance, casually described the Taino as “innumerable, for I believe there to be millions upon millions of them.” Las Casas claimed the population to be “more than three million.” Modern researchers have not nailed down the number; estimates range from 60,000 to almost 8,000,000. A careful study in 2003 argued that the true figure was “a few hundred thousand.” No matter what the original number, though, the European impact was horrific. In 1514, twenty-two years after Colon’s first voyage, the Spanish government counted up the Indians on Hispaniola for the purpose of allocating them among colonists as laborers. Census agents fanned the across the island but found only 26,000 Taino. Thirty-four years later, according to one scholarly Spanish resident, fewer than 500 Taino were alive….

Spanish cruelty played its part in the calamity, but its larger cause was the Columbian Exchange. Before Colon none of the epidemic diseases common in Europe and Asia existed in the Americas. The viruses that cause smallpox, influenza, hepatitis, measles, encephalitis, and viral pneumonia; the bacteria that cause tuberculosis, diphtheria, cholera, typhus, scarlet fever, and bacterial meningitis — by a quirk of evolutionary history, all were unknown in the Western Hemisphere. Shipped across the ocean from Europe these maladies consumed Hispaniola’s native population with stunning rapacity. The first recorded epidemic, perhaps due to swine flu, was in 1493….

Map of Hispaniola

Joan Vinckeboons, “Map of the islands of Hispaniola and Puerto Rico,” 1639(?)


Follow-Up Assignment

Mann describes in excerpt three a major change in Taino population on Hispaniola and the effects of this change on the Taino population and the Spanish. But another group was also affected — enslaved Africans. The Spanish used the encomienda system in Hispaniola, whereby conquistadors were given large plantations as well as the Indian slave labor of all who lived on the plantation. Through this system the Spanish moved quickly to enslave Indians, even though the official mission of the Spanish was to Christianize them. In response to pressure from the Catholic Church, in 1542 King Carlos V banned Indian slavery, opening the way for African slaves. Mann writes,

By 1501, seven years after La Isabella’s founding, so many Africans [as slaves] had come to Hispaniola that the alarmed Spanish king and queen instructed the island’s governor not to allow any more to land [but]…the colonists saw that the Africans appeared immune to disease, didn’t have local social networks that would help them escape, and possessed useful skills — many African societies were well known for their ironworking and horsemanship. Slave ships bellied up to the docks of Santo Domingo in ever-greater numbers. The slaves were not as easily controlled as the colonists had hoped [and]…. No longer were Africans slipped into the Americas by the handful. The rise of sugar production [sugar production is very labor intensive] in Mexico and the concurrent rise in Brazil opened the floodgates. Between 1550 and 1650…slave ships ferried across about 650,000 Africans, with the total split more or less equally between Spanish and Portuguese America…. Soon they [Africans] were more ubiquitous [existing everywhere] in the Americas than Europeans, with results the latter never expected. (Mann, p.387–388)

What do you believe might have been some of the “results the latter [the Europeans] never expected”? In what ways can New World slavery be said to be related to the Columbian Exchange? Discuss the possible unintended consequences with your classmates. Use specific examples as evidence.

Vocabulary Pop-Ups

  • menagerie: collection of wild or unusual animals
  • alien: foreign, hostile
  • depredation: ravages
  • bedlam: wild confusion
  • entomologist: insect expert
  • phenomenon: observable event or fact
  • dismayed: alarmed
  • speculation: thoughtful opinion
  • culprit: villain
  • horrific: causing horror
  • fanned: spread out
  • calamity: great disaster
  • quirk: peculiar action
  • maladies: chronic diseases
  • rapacity: fierce hunger


  • Charles C. Mann, 1493: Uncovering the New World Columbus Created (New York: Vintage Books, 2012).


  • Bouttats, Pieter Balthazar, 1666–1755, engraver. : El almirante Christoral Colon descubre la Isla Española, iy haze poner una Cruz, etc. / P. B. Bouttats fec., Aqua forti. [1728] Library of Congress Rare Book and Special Collections Division Washington, D.C. 20540 USA (accessed September 15, 2014).
  • Histoire Naturelle des Indes, Illustrated manuscript. ca. 1586. Bequest of Clara S. Peck, 1983 MA 3900 (fol. 71v–72) The Morgan Library and Museum, New York.
  • Vinckeboons, Joan. Map of the islands of Hispaniola and Puerto Rico. Map. [1639?] Pen-and-ink and watercolor. Library of Congress Geography and Map Division Washington, D.C. 20540-4650 USA (accessed September 15, 2014)
  • De insulis nuper in mari Indico repertis [Christopher Columbus discovering America]. Woodcut, 1494. Library of Congress Rare Book and Special Collections Division Washington, D.C. 20540 USA Illus. in Incun. 1494 .V47 Vollbehr Coll [Rare Book RR] (accessed September 29, 2014).
  • Christopher Columbus leaving Spain to go to America. London : J. Edwards, 1800? 1 print : engraving. Illus. in: America, part 4 / Theodore de Bry, 1528-1598, ed., 1800?, plate VIII. Library of Congress Miscellaneous Items in High Demand Collection (accessed September 29, 2014).
  • Christophe Colomb parmi les Indiens / lith. de Turgis. Paris : Vve. Turgis, [between 1850 and 1900]. Library of Congress Prints and Photographs Division Washington, D.C. 20540 (accessed September 29, 2014).
  • Histoire Naturelle des Indes, Illustrated manuscript. ca. 1586. Bequest of Clara S. Peck, 1983 MA 3900 (fol. 11v–12) The Morgan Library and Museum, New York.