The arrival of Europeans in the Americas had a profound effect not only on the Americas but also on the world as a whole. For the first time, there would be a sustained connection between the Old World (Europe, Asia, and Africa) and the New World (North America and South America). The exchange of culture, technology, disease, plants, and animals between the two worlds would become known as the "Columbian Exchange" and would lead to an interconnected globe.
The impact Europeans had on native civilizations is generally considered to have been negative. Although new technology and food were introduced to the Americas by Europeans, many of the thriving native civilizations were destroyed as Europeans craved greater territorial control over the Americas and the plentiful valuable resources they contained. One of the biggest threats to indigenous civilization came through the introduction of diseases like smallpox. Europeans had developed greater immunity to diseases like smallpox, whereas Native American immune systems had not been previously exposed to these new diseases and were not able to fight them off. In the centuries following European arrival in the Americas, there was a severe drop in the native population. This drop is largely due to the introduction of new deadly diseases. (However, it is equally important to note that the population also dropped due to systemic and intentional violence perpetrated by the Europeans.)
Native Americans and Europeans also clashed on ideas regarding land ownership. European colonizers saw land as something that could be owned by an individual. This meant they could use the land as they saw fit and could keep others off their land. This led to clashes with many of the natives, who did not see land as something one could maintain private ownership of. The indigenous peoples viewed land as more of a resource that could be shared for the greater good.
Europeans also had an impact on the environment in the Americas. The popularity and value of beaver pelts led to the arrival of great numbers of fur traders and hunters from Europe. The high demand eventually led to a significant decline in the beaver population in the Americas, as hunters sought them out in the name of profits. In some regions of North America, the beaver faced near-extinction. The loss of the beaver—a key part of the ecosystem—led to decreases in populations of other creatures that relied on the beaver for their own survival.
Europeans also introduced pigs to the New World. Pigs, when released to search for food sources, proved destructive as well. Pigs competed with animals native to the New World for food sources, and they can be seen as an invasive species.
Europeans also found the environment of the Americas suitable for certain cash crops which they struggled to develop in Europe. Tobacco, cotton, and sugar became central factors in making European colonization profitable. New plant-based foods would also be introduced to Europe from the Americas. Staple foods, such as potatoes, tomatoes, corn, and peanuts, which were native to the New World would be introduced and become popular in Europe.
The major impact of Native Americans on Europeans could be their knowledge of the Americas. In a number of cases, early colonists in the Americas relied on the knowledge of indigenous people to survive harsh conditions. This would ultimately prove to hasten the downfall of many native cultures.
Contact between Europeans and Native Americans brought the world into a new, unprecedented interconnected era. The contact between the "Old World" and the "New World" would lead to the introduction of new foods, technologies, and ideas to people who had not yet been exposed to them. It would, however, also lead to the introduction of new diseases and the destruction of entire civilizations as well. Over the next few centuries, the Americas would change from continents controlled by Native Americans to continents dominated by European colonizers.