CLAY CENTER, Kan. — In this rural swath of northern Kansas, where the grass rolls thick and green to the horizon, a white cross dominates the landscape.

Kathy Martin, a member of the state Board of Education, built it on her farm this spring, gathering weathered chunks of limestone from the horse pasture and laying them on a hillside.

The cross is a proud expression of Martin's faith. And as hearings challenging the role of evolution in the state's school-science curriculum began yesterday, that cross left little doubt about where she stands in the debate.

"Evolution is a great theory, but it is flawed," said Martin, 59, a retired science and elementary-school teacher who is presiding over the hearings. "There are alternatives. Children need to hear them. We can't ignore that our nation is based on Christianity, not science."

The hearings in Topeka center on two proposals. The first recommends that students continue to be taught the theory of evolution because it is key to understanding biology. The other proposes that Kansas alter the definition of science, not limiting it to theories based on natural explanations.

Whichever curriculum proposal the board adopts, members say, it would serve only as a guideline for teachers. But the standards determine what is included on statewide tests, and students would be required to learn that material.

"Part of our overall goal is to remove the bias against religion that is in our schools," said William Harris, a chemist who was the first witness to speak yesterday on behalf of changing the state's curriculum.

Dozens of national and state science organizations are boycotting the hearings, which they see as an effort to introduce creationism and intelligent design into the classroom. Intelligent design is a concept that asserts life on Earth is so complex that a higher power must have played a role in its creation.

"Public hearings and votes are not how the truth of science is determined," said Harry McDonald, president of Kansas Citizens for Science.

The debate over Kansas' curriculum, political experts say, reflects a broader effort by conservative Christian groups to move their agendas forward by electing like-minded officials at the state and local levels. GOP gains in November gave the Kansas board a 6-4 conservative majority.

"They have created a straw man," said Jack Krebs, vice president of Kansas Citizens for Science. "They are trying to make science stand for atheism, so they can fight atheism."

Take away the television cameras and the PowerPoint presentations and the scene yesterday bore a resemblance to the 1925 Scopes trial in Dayton, Tenn., where a high-school science teacher was famously convicted of violating a state law forbidding the teaching of evolution. Only this time, said Bruce Chapman, who heads Seattle's Discovery Institute, which promotes intelligent design, "This is the Scopes trial turned on its head."

Pedro Irigonegaray, a lawyer defending evolution in the debate, predicted a "whitewash" but said he would fight nonetheless.

In his testimony, Harris, the chemist, disputed the accepted wisdom that ancient simple life forms became ever more complex, evolving over billions of years into a multitude of life forms. He also said it would not be an "irresponsible deduction from the data" to say the genetic code contained in DNA was produced by an intelligent "mind."

Harris said educators who teach evolution introduce religion by rejecting the possibility that God created the universe and all living things.

Asked where he saw atheism in the Kansas science standards, Harris replied, "I see it between the lines."