Final answer:
The northern half of Mexico had a population mainly composed of various Indigenous groups prior to Spanish colonization. Post colonization and historic events like Hidalgo's rebellion and migrations due to the Mexican Revolution, resulted in a mix that included European settlers and mestizos. The Southwestern United States now continues to reflect this heritage with significant Hispanic populations.
Step-by-step explanation:
The original population of the northern half of Mexico was diverse and included various Indigenous groups before the Spanish colonization. After the colonization, the area underwent significant changes, especially with the advent of Spanish settlers. Over time, especially due to events such as Hidalgo's rebellion, the Mexican Revolution, and the land reforms in the early 20th century, there was a mix of Indigenous people, people of mixed race known as mestizos, and European settlers. The demographic dynamics were further influenced by migration patterns, which included movements into the United States during periods of turmoil and land rushes.
Historically, northern Mexico's transition into part of the United States had implications for the population mix. Post the Treaty of Guadalupe Hidalgo, many Mexican citizens became part of the United States against their choice, and according to the treaty, had the option to become naturalized U.S. citizens, influencing the demographic development. Today, the Southwest states, which were once part of Mexico, like Texas and New Mexico, have significant Hispanic populations due to these historic migrations and demographic changes.
In summary, the original population in northern Mexico primarily consisted of Indigenous populations and was supplanted over time by European influences and mixed populations due to colonization, migration, and political changes. The areas that are now the Southwestern United States have retained a strong Hispanic heritage, reflected in the significant percentage of Hispanic or Latino populations in these states today.