How did Darwin's theory of evolution influence American thinking about race?

I know the answer but i don't rememmber it so sorry

Darwin saw sexual selection, in which basically trivial preferences shaped the appearances of populations over time, as a means by which races with a common origin could have acquired their visible differences.

Darwin thus emphasised human unity and dwelt upon superficial differences, while acquiescing in the contemporary assumption that some races were superior to others.

Explanation:

In his book The Descent of Man, he theorized that man, having evolved from apes, had continued evolving as various races, with some races more developed than others. Darwin classified his own white race as more advanced than those “lower organisms” such as pygmies, and he called different people groups “savage,” “low,” and “degraded.”

when world war i broke out across europe in 1914, president woodrow wilson proclaimed the united states would remain neutral, and many americans supported this policy of nonintervention. however, public opinion about neutrality started to change after the sinking of the british ocean liner lusitania by a german u-boat in 1915; almost 2,000 people perished, including 128 americans. along with news of the zimmerman telegram threatening an alliance between germany and mexico, wilson asked congress for a declaration of war against germany. the u.s. officially entered the conflict on april 6, 1917.

the first two years of american revolution was not very encouraging for the patriots since the british were far superior in sea power, arms and troops.