for the environmental and demographic history of all the regions involved. In the process known as the Columbian Exchange, numerous plants, animals, and diseases were transplanted—both deliberately and inadvertently—from one continent to another. The epidemiological impact of this exchange on the indigenous peoples of the Americas was profound, causing very high death rates and population declines of 50% to 90% or even 100%. European and African immigrants also had very high death rates on their arrival, but they could be and were replaced by new shipments of immigrants (see the Population history of American indigenous peoples). Many foods that are common in present-day Europe, including corn (maize) and potatoes, originated in the New World and were unknown in Europe before the 16th century. Similarly, some staple crops of present-day West Africa, including cassava and peanuts, originated in the New World. Some of the staple crops of Latin America, such as coffee and sugarcane, were introduced by European settlers in the course of the Columbian Exchange. Slavery and labor The slave trade played a role in the history of the Atlantic World almost from the beginning. As European powers began to conquer and claim large territories in the Americas in the 16th and 17th centuries, the role of chattel slavery and other forced labor systems in the development of the Atlantic World expanded. European powers typically had vast territories that they wished to exploit through agriculture, mining, or other extractive industries, but they lacked the work force that they needed to exploit their lands effectively. Consequently, they turned to a variety of coercive labor systems to meet their needs. At first the goal was to use native workers. Native Americans were employed through Indian slavery and through the Spanish system of encomienda. Indian labor was not effective on a large scale for complex reasons (e.g., high death rates and relative ease of escape to Native communities), so plantation owners turned to African slaves via the Atlantic slave trade. European workers arrived as indentured servants or transported felons who went free after a term of labor. In short, the Atlantic World was one of widespread inequality where the exploitation of human labor provided the foundation for a small handful of elites to reap enormous profits. The Trans-Atlantic Slave trade played a massive role in shaping the demographics of the Americas, especially in areas where huge plantations were the norm, such as in