<P> The term was coined by Florentine explorer Amerigo Vespucci . The Americas were also referred to as the "fourth part of the world". </P> <P> The terms "Old World" vs. "New World" are meaningful in historical context and for the purpose of distinguishing the world's major ecozones, and to classify plant and animal species that originated therein . </P> <P> One can speak of the "New World" in a historical context, e.g., when discussing the voyages of Christopher Columbus, the Spanish conquest of Yucatán and other events of the colonial period . For lack of alternatives, the term is also still useful to those discussing issues that concern the Americas and the nearby oceanic islands, such as Bermuda and Clipperton Island, collectively . </P> <P> The term "New World" is used in a biological context, when one speaks of Old World (Palearctic, Afrotropic) and New World species (Nearctic, Neotropic). Biological taxonomists often attach the "New World" label to groups of species that are found exclusively in the Americas, to distinguish them from their counterparts in the "Old World" (Europe, Africa and Asia), e.g. New World monkeys, New World vultures, New World warblers . </P>

What was the single most important thing the spanish brought to the new world