The importance of evolution as the fundamental explanatory principle in biology has been affirmed by the American Association for the Advancement of Science (1993), the National Academy of Sciences (1998), and the National Science Teachers Association (2003). It is therefore expected that evolution should be prominent in the life science standards--documents to which biology teachers can refer as to what their state considers to be essential learning in their discipline--in all states. This is, however, not the case (Cavanagh, 2005; Gross, 2005). Variation in state standards in evolution results from both debate within boards that write them as well as well-publicized efforts of special interest groups to influence their decisions, usually by seeking reduced treatment of evolution or adding some form of creationism such as "intelligent design" (Wallis, 2005). Additionally, state legislatures have become increasingly active in this area. According to the National Center for Science Education (www.natcenscied.org), legislative attempts to modify the curriculum are increasingly common, occurring in 12 states in 2005 and 11 in 2006, compared to an average of five states/year in 2002-2004.
These battles over science standards regarding evolution speak to their perceived importance in determining what is covered in science classrooms. If standards are important, then states with better standards should have better science teaching in their public schools. In 2000, Lerner published a study sponsored by the Fordham Foundation comparing state standards regarding the teaching of evolution. He reviewed standards from 49 states and the District of Columbia, and graded the standards based on their treatment of evolution. Indiana and nine other states received a grade of A ("very good or excellent"), while 12 states, including Ohio, received a grade of F ("useless or absent"). The standards Lerner reviewed for Indiana were part of the Indiana Science Proficiency Guide adopted in 1997. These standards, and those that replaced them in 2000 (Indiana's Academic Standards), both contained a specific section on evolution with explicit competencies in topics such as natural selection, adaptation, and evidence for evolutionary change.
The Ohio standards examined by Lerner were contained in Science: Ohio's Model Competency-Based Program adopted in 1994. There was no section on evolution, and only a few competencies included evolutionary topics such as natural selection. The word "evolution" was not used in a biological context.
The dramatic difference in the state standards in two neighboring states provided an opportunity to test the hypothesis that state standards influence curricula. The hypothesis predicts that, in public high school biology courses in Indiana compared to those in Ohio, (1) evolution should receive more classroom time, and (2) teacher explanations for the diversity of life should be more likely to emphasize evolution. Previous studies have surveyed high school biology teachers (reviewed in Moore, 2002). My interest, however, was in how students perceived evolution coverage. Ideally, the predictions above could best be tested by a survey given to Indiana and Ohio high school students who had just completed their first biology course; however, many public school systems are reluctant to participate in such a survey (Moore et al., 2006). As an alternative, students were surveyed about their high school biology while taking their first college biology course for majors at state universities in Indiana and Ohio.
The survey began with a statement printed on the form and also read aloud by the instructor, informing the students that participation was voluntary and would not influence their grades in the course. Students were instructed not to put their names on the form. There followed eight questions that generated a description of where and when the student's first high school biology course was taken, the number of years of biology completed in high school, and the nature of the high school (public, private, or parochial). …