Dr. Scott became a leader of opponents of the measure. “I was one of the few people on campus who knew what this stuff was about,” she said. It took two years, but eventually the school board rejected the proposal.

At the same time, evolutionary biologists like Stephen Jay Gould of Harvard University and Niles Eldredge of the American Museum of Natural History, along with Jack Friedman, then a teacher in Syosset, N.Y., were organizing what Mr. Friedman called “committees of correspondence” to encourage science teachers all over the country to follow the controversy over evolution and to keep in touch. A result of all this activism was the establishment, in 1983, of the N.C.S.E.

Meanwhile, Dr. Scott was losing a fight for tenure at the University of Kentucky. In 1986, she saw an ad for a national director for the science center. She got the job.

Today the organization, based in Oakland, Calif., has a staff of 14 — not all full-time, Dr. Scott said — and an annual budget of about $1.5 million, raised from private foundations and its approximately 5,000 members. When creationist efforts arise, N.C.S.E. helps local people fight them.

“We can give them the advice we have amassed from similar groups over the years,” Dr. Scott said. “Our joke is we run grass-roots organizations from the top down.”

In addition to reports and a weekly newsletter, it has produced a book, “Evolution vs. Creationism.” A recent issue of the newsletter reports that a new poll finds that more residents of Georgia believe in creationism than in evolution. As Dr. Scott said she saw in the Gavan-Gish debate long ago, merely providing information is not enough. “You do not solve the creation-evolution issue just by throwing science at it,” she said.

She is particularly distressed to hear people assert that belief in evolution is incompatible with religious faith. Though Dr. Scott described herself as a “humanist” who is not religious, she said, “there is not a dichotomous division between people of faith and science. There are many people of faith who accept evolution. This is something many people do not realize.”