What was considered Evolutionary Science or Biology proper in 1880-1890 in the US?

I encountered an insightful article that may address the origins of Veblen's work. Here is an excerpt:

A number of economists and other social scientists have addressed evolutionary explanations. There is a large and valuable literature that considers how humans have evolved in groups and how human propensities for altruism and cooperation have emerged, alongside more selfish and competitive tendencies.........But Veblen made an even more radical point, which is still difficult for many economists to swallow. He argued that the idea of the utility-maximizing individual is inconsistent with the principle of evolutionary explanation. This point remains pertinent, because the idea of a fixed utility function – even if it is one that has “social” or “altruistic” preferences – lacks a clear evolutionary and causal explanation of its origins. It is simply assumed.

Here is the link to the article: https://evonomics.com/imagine-economics-evolutionary-science/#:~:text=In%201898%2C%20the%20great%20American,the%20social%20and%20behavioral%20sciences.

I hope this helps!