The board was set to vote on last-minute changes Tuesday to lesson plans on evolution to address concerns of scientists lobbying the board over their content, said board president Jennifer Sheets.
The board's standards committee approved the changes to strengthen the plans' scientific grounding Monday afternoon.
For example, the changes delete references to all Web sites, including those for and against evolution, and add language referring to the methods scientists use to test predictions.
The Ohio Academy of Science has said the lesson plans include anti-evolution positions pushed by backers of the alternate "intelligent design" theory, which says change over time was not random and that life is so complex it must have been designed by a non-specified power.
"As long as we're sure the process is grounded in science, it's not the subject matter that matters so much," Sheets said Monday. "That's what we've tried to do - make sure this lesson is evaluating information based on the scientific method."
At issue is a 10th-grade lesson plan, "Critical Analysis of Evolution," a 22-page portion of a 547-page science lesson plan for all grades.
The academy's position is backed by Case Western Reserve University's faculty senate, a governing body that voted March 2 to oppose the plan.
Several other scientists, including some who support intelligent design, say the lesson plan correctly encourages students to analyze the theory of evolution.
A group of 22 scientists wrote the board last week encouraging it to allow debate on disagreements over evolutionary theory.
"We need to look at things critically," said Al Gotch, chairman of Mount Union College's chemistry department and one of those who signed the letter. "Scientists are not born skeptics, they're trained to be skeptics, and it seems to me this fits in with that process."
Gotch, 42, said he supports the intelligent design concept, and that the lesson plans on evolution should place both sides of the issue before students and permit discussion.
The letter was promoted this week by the Seattle-based Discovery Institute, which supports scientists studying intelligent design and says states should teach both evolution and scientific criticism of evolutionary theory.
Critics of the lesson plan say the plan includes many of the concepts found in "Icons of Evolution," a book by Jonathan Wells, a senior fellow at the institute.
The state board removed a reference to Wells' book from an earlier draft. Any connection between the book and the plan "seems inconsequential at best," John West, associate director of the institute's Center for Science and Culture, said in a letter to Sheets last week.
Another scientist, anthropologist Cynthia Beall, said the lesson plan misrepresents scientific terms and includes several elements of intelligent design without using the term.
"There's a religious way of explaining things that's based in religion and belief - when you know something that way, you don't know it scientifically," Beall said. "When you know something in science, you know it from evidence and scientific testing."