AUSTIN, Tex.  The latest round in a long-running battle over how evolution should be taught in Texas schools began in earnest Wednesday as the State Board of Education heard impassioned testimony from scientists and social conservatives on revising the science curriculum.

The debate here has far-reaching consequences; Texas is one of the nation’s biggest buyers of textbooks, and publishers are reluctant to produce different versions of the same material.

Many biologists and teachers said they feared that the board would force textbook publishers to include what skeptics see as weaknesses in Darwin’s theory to sow doubt about science and support the Biblical version of creation.

“These weaknesses that they bring forward are decades old, and they have been refuted many, many times over,” Kevin Fisher, a past president of the Science Teachers Association of Texas, said after testifying. “It’s an attempt to bring false weaknesses into the classroom in an attempt to get students to reject evolution.”