The correct answer to this open question is the following.
The differences between the types of slavery traditionally practiced in Africa and the slavery that developed in the New World were basically the following.
African slaves were the by-product of the consequences of wars between African tribes. The one that won the war, conquered the territory, and forced people into slavery. The victorious tribe did no see slavery as a form of property but as a form of punishment.
Slavery in the new world was different. For white Europeans in the North American territory, slaves represented a form of property. That is what they considered when they bought slaves during the Slave Trade period. In the Americas, Africans were slaves for life and depended only on the landlord.
Other types of servitude such as European serfdom compared to slavery because it also exploited not only Africans but the Native Indians. For instance, when Spaniards conquered the American territory of what today is México, the Caribbean Islands, and South America, they instilled the Encomienda, a form of slavery, where Native Indians worked in the farm fields for long hours in exchange of housing and some food.
