Final answer:
Native American slavery changed to African slavery due to diseases decimating the Native population and the resilience of African slaves who could withstand the harsh plantation conditions. The racial nature and scale of African slavery in the New World differed from past labor systems.
Step-by-step explanation:
The practice of Native American slavery changed over time primarily because Native Americans were dying from diseases and the harsh conditions of slavery. As a result, African slaves were increasingly brought to the Americas to fulfill the need for a resilient workforce suitable for labor-intensive plantations. The choice to use African slaves over indentured servants or Native Americans was influenced by the fact that Africans were not indigenous to the Americas, making escape and resistance more difficult, were immune to many European diseases, and were supplied in large numbers through the well-established trans-Atlantic slave trade.
The way African slavery in the New World differed fundamentally from past instances of slavery was through its race-based nature and its scale, with millions forcibly transported across the Atlantic Ocean in brutal conditions. This system of slavery was characterized by its permanence, legal codification, and the belief in racial inferiority, which was not as prevalent in other systems of labor during the same era.