Darwin Day, conceived as a way to promote science on the 202nd anniversary of Charles Darwin’s birth — he was born Feb. 12, 1809 — had until this time been commemorated mostly by those inclined to science, at natural history museums, by secular humanist groups and in university biology departments.

Image Charles Darwin’s birthday was remembered in 475 celebrations across the United States. Credit... Associated Press

“Maybe this year,” Jory P. Weintraub, the education director at the evolutionary synthesis center, proposed to his colleagues last fall, “we should try to go to places that wouldn’t otherwise have a Darwin Day.”

Craig McClain, a marine biologist at the center who studies giant squid, was initially opposed.

“You want to send evolutionary biologists out to rural America?” Dr. McClain asked. “On purpose?”

He recalled previous clashes between scientists and religious conservatives in some rural communities over Darwin’s theory of evolution.

Nineteen schools agreed to host the scientists, but negotiating the terms of the visit was sometimes a delicate process: The goal, they assured a principal who worried about their ideological agenda, was simply to tell students why science was “cool” and perhaps interest them in a career. Still, if questions about religion and science arose, they reserved the right to answer them.