The late-nineteenth-century theoretical perspective, which emphasized that the development of culture progressed through a series of successive stages, was called

Unilineal evolution,

Explanation:

The unilineal evolution is a concept from Anthropology and Social science that was pretty popular in the 19th as it came to portray the West as an evolved form of culture over the rest of forms of life in other parts of the world.

This idea based mainly in the works of Taylor, who extended Darwinistic notions into the study o  culture, and argued how a progressive form of culture will evolve from an old root that will resemble a simple organism forming complex tissue over time.

Through gradually stages of development enabled the West to become the dominant and evolved form of all.

However accepting this, often meant portraying other people as savages, and any primitive form of culture often went underestimated.

This notion is highly debated of often History has shown how  this perception has lead to negative outcomes.

most cajuns resided in acadiana, where their descendants are still predominant

no because it could make the world a terrible place to live in.