If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Main content

Environmental and health effects of European contact with the New World

European arrival in the Americas decimated both indigenous people and previously-flourishing ecosystems. 


  • Colonization ruptured many ecosystems, bringing in new organisms while eliminating others.
  • The Europeans brought many diseases with them that decimated Native American populations.
  • Colonists and Native Americans alike looked to new plants as possible medicinal resources.

Environmental changes

The European presence in America spurred countless changes in the environment, negatively affecting native animals as well as people. The popularity of beaver-trimmed hats in Europe, coupled with Native Americans’ desire for European weapons, led to the overhunting of beavers in the Northeast. Soon, beavers were extinct in New England, New York, and other areas. With their loss came the loss of beaver ponds, which had served as habitats for fish as well as water sources for deer, moose, and other animals. Furthermore, Europeans introduced pigs, which they allowed to forage in forests and other wildlands. Pigs consumed the foods on which deer and other indigenous species depended, resulting in scarcity of the game native peoples had traditionally hunted.
European ideas about owning land as private property clashed with indigenous people's understanding of land use. Native Americans did not believe in private ownership of land; instead, they viewed land as a resource to be held in common for the benefit of the group. Colonizers erected fields, fences, and other means of demarcating private property. Indigenous people who moved seasonally to take advantage of natural resources now found areas off-limits, claimed by colonizers.
Colonists trading furs of overhunted beavers. Photo courtesy of Wikimedia Commons.

Introduction of disease

Perhaps the single greatest impact of European colonization on the North American environment was the introduction of disease. Microbes to which native inhabitants had no immunity caused sickness and death everywhere Europeans settled. Along the New England coast between 1616 and 1618, epidemics claimed the lives of 75 percent of the indigenous people. In the 1630s, half of the Huron and Iroquois people living near the Great Lakes died of smallpox. The very young and the very old were the most vulnerable and had the highest mortality rates. The loss of the older generation meant the loss of knowledge and tradition, while the deaths of children only compounded the trauma.
Some indigenous people perceived disease as a weapon used by hostile spiritual forces, and they went to war to exorcise the disease from their midst. These “mourning wars” in eastern North America were designed to gain captives who would either be adopted or ritually tortured and executed to assuage the anger and grief caused by loss.
An engraving by Samual Eastman of Native Americans afflicted by disease. Photo courtesy of Wikimedia Commons.

New plants make new medicines

European expansion in the Americas led to an unprecedented movement of plants across the Atlantic. A prime example is tobacco, which became a valuable export as the habit of smoking took hold in Europe. Another example is sugar. Columbus brought sugarcane to the Caribbean on his second voyage from Spain in 1493, and thereafter a wide variety of other herbs, flowers, seeds, and roots.
Notably, Europeans traveled to America to discover new medicines. The task of cataloging the new plants found there led to the emergence of the science of botany. Early botanists included the English naturalist Sir Hans Sloane, who traveled to Jamaica in 1687 and there recorded hundreds of new plants.
Early English botanist Hans Sloane. Photo courtesy of Wikimedia Commons.
Native Americans, who possessed a vast understanding of local New World plants and their properties, would have been a rich source of information for those European botanists seeking to find and catalog potentially useful plants. Enslaved Africans, who used medicinal plants in their native land, adapted to their new surroundings by learning the use of New World plants through experimentation and from the indigenous inhabitants. Native Americans and Africans employed their knowledge effectively within their own communities.

What do you think?

How did the environment of the Americas suffer from European contact? How did it benefit?
Did the markets in Europe influence the development of botany and agriculture in the New World? How so?
How did indigenous people and colonists exchange both knowledge and materials to make new medicines?

Want to join the conversation?

  • hopper jumping style avatar for user Yago
    Did the african slaves and the natives co-operate in trying to work against the colonists? Or did they not have much contact with each other?
    (32 votes)
    Default Khan Academy avatar avatar for user
    • duskpin tree style avatar for user Caitlyn peacock
      White colonists feared that slaves, indentured servants, and Indians would collaborate because if they did, they'd be able to outnumber the colonists.Therefore they tried their hardest to keep them separate in a multitude of ways. Some colonists actually occasionally ran off to live with Indians because they liked their lifestyle
      better or because they had more food than the colonists, the latter was a more likely reason when colonists first began to settle in America.
      (32 votes)
  • boggle purple style avatar for user Rose
    What changed the European's minds to want tobacco?
    (16 votes)
    Default Khan Academy avatar avatar for user
    • aqualine tree style avatar for user David Alexander
      Once a person is accustomed to it, smoking of tobacco is not unpleasant. So, for the pleasantness, people started it. However, the nicotine in tobacco is also an addictive drug. So it wasn't long before people who started using tobacco for pleasure became tobacco addicts.
      American tobacco companies latched onto this long ago, and gave cigarettes for free to members of the military (four of them in every box of C Rations) to get young men hooked and turn them into addicts for life. The tobacco companies made millions of dollars, and American men died of tobacco related conditions, also by the millions.
      (19 votes)
  • primosaur tree style avatar for user Ben
    did the Europeans even know that tobacco was bad for you back then
    (9 votes)
    Default Khan Academy avatar avatar for user
  • aqualine sapling style avatar for user Michel Ostiguy
    The Europeans brought diseases to the new world that native Americans had no immunity against. How come the reverse didn't happen? Were there not diseases that native Americans had that Europeans had no immunity against?
    (12 votes)
    Default Khan Academy avatar avatar for user
    • blobby green style avatar for user nglapex
      Good question! While it is true that European immune systems were stronger, they did experience new diseases when arriving to the New World. However, the natives were mostly eager to help the new settlers with their means of healing those diseases. As an example you could use Jacques Cartier, “Jacques Cartier’s Second Voyage to the St. Lawrence River and Interior of “Canada,” 1535-1536. In this story, Europeans got a disease fairly unknown to them (in retrospect, this was probably a form of scurvy). When they noticed a boy that was magically healed from it through the sap of a certain tree, they used it to heal themselves. Then cut it all down, cuz yeah, Europeans saw good money in it.
      (11 votes)
  • blobby green style avatar for user iee6308
    why did the natives get punished even though they didnt do anything
    (7 votes)
    Default Khan Academy avatar avatar for user
    • aqualine tree style avatar for user David Alexander
      The White Europeans regarded the native population as less than human, as beasts of burden to be exploited for the profit of adventurers from Europe and investors IN Europe. When the native populations were sufficiently decimated to no longer be of use for profit-producing labor, the White Europeans resorted to enslavement of Africans (also considered less than human) to do the work.
      (12 votes)
  • blobby green style avatar for user manaal.akhtar
    What were the positive and negative impacts of introducing new trade goods/technologies on the Europeans and the Native Americans?
    (5 votes)
    Default Khan Academy avatar avatar for user
    • aqualine tree style avatar for user David Alexander
      That looks like your homework. I suggest that you pick a particular technology or trade good, such as "firearms". Now think through how the introduction of such a technology might be good for the Native Americans, and bad for the Europeans. Also, consider how it might be good for the Europeans and bad for the native Americans, then write your answer.
      Having completed that one, go on to things like steel knife blades and arrow heads. I'm sure you can figure it out, and write a very good response.
      (11 votes)
  • piceratops tree style avatar for user kj033ps
    Are there any significant battles in history that can be identified as "mourning wars"?
    (7 votes)
    Default Khan Academy avatar avatar for user
    • starky seedling style avatar for user Aaron Ghosh
      Mourning wars also known as "vengeance raids," was a vital part of Iroquois culture. These wars were fought for psychological and spiritual reasons. In these conflicts, warriors would fight to avenge the deaths of warriors killed in previous battles. The Iroquois nations practiced a form of warfare called mourning wars, which were raids to avenge the warriors killed in a previous battle. Mourning wars did not expand the Iroquois borders, and they did not make the Iroquois richer. What they did was provide an outlet for grief and mourning.
      (6 votes)
  • leaf green style avatar for user bryan.padilla21
    How did Europeans kill the indians
    (6 votes)
    Default Khan Academy avatar avatar for user
    • primosaur sapling style avatar for user Goldleaf
      The European settlers killed Native Americans both intentionally and unintentionally. Intentionally, they did it using guns or some sort of weapon; one time they even gave them blankets they had exposed to smallpox virus. Unintentionally it was mainly through disease, as the Native Americans had no immunity to the bacteria and viruses the Europeans brought.
      (7 votes)
  • blobby green style avatar for user Orantes Diana
    did Europeans know smoking was bad for them?
    (3 votes)
    Default Khan Academy avatar avatar for user
  • starky seed style avatar for user Hisoka
    How many bad things did the Natives survive through, of course the population declined 75% by 2021 but, did the europeans have a big role in this or a small role. But it's true that the europeans have also helped them, as said one person discovered 100 new plants to which the natives created cures and also new medicines. Which again the europeans wanted this knowledge for the present and older generation by 1687. So were the europeans more helpful or harmful?
    (2 votes)
    Default Khan Academy avatar avatar for user