The theory of evolution is universally accepted among scientists.
The issue is not so cut-and-dry in U.S. high school science classes, with most public school teachers hesitating to fully endorse it, according to a study published Friday in Science magazine.
Influenced by personal beliefs or attempting to avoid controversy, science educators use a “variety of approaches” to teach evolution, “all of which tend to cheat students out of a rigorous science education,” said Eric Plutzer, who conducted the study with Michael Berkman. Both are political scientists at Pennsylvania State University in University Park, Pa.
“Supporters of evolution, scientific methods and reason itself are losing battles in America’s classrooms,” Plutzer and Berkman write in the article about their study.
The biggest detractors of effective instruction on evolutionary biology are not teachers who actively cover non-scientific ideas on the origins of life, such as creationism and intelligent design, stated Plutzer in an interview. Rather, it’s the teachers who do not cover it adequately, he said.
“Four times as many students are getting poor instruction in evolution as are being enthusiastically taught creationism,” Plutzer said.
The study surveyed 926 public high school biology teachers across the U.S. and found that nearly two-thirds of them don't strongly advocate evolutionary biology or any other alternative explanation for the origin of life.
About 13 percent of high school biology teachers spent at least an hour in their science classes presenting creationism or intelligent design in a positive light, the researchers found when they analyzed data from the National Survey of High School Biology, which conducted the sampling of the 926 science educators.
An added 5 percent of science teachers reported validating creationism in passing or when asked by students, the study said.
Creationism and intelligent design challenge the theory of evolution and include the participation of God or of a supernatural intelligent agent in explanations of nature. These ideas of the origins of life and the universe cannot be proven using the scientific method, according to to the National Research Council.
Only 23 percent of teachers taught evolutionary biology as recommended by the NRC, according to the data. The council endorses incorporating evolution into teaching about other biological concepts.
Evolution is often taught as a stand-alone topic, using only the fossil record as evidence, when it is “the foundation for all areas of biology,” said Jay Labov, senior adviser for education and communication at the NRC.
Students need to understand “how evolution is occurring now,” he said.
The theory of evolution is not limited to the process of change over time that leads to different species suited to their own environments. It also explains how bacteria develop antibiotic resistance, according to the NRC.
Teachers are under pressure to downplay or eliminate the teaching of evolution, Plutzer notes in the study report.
There are three significant choices teachers make that detract from a strong grounding in evolution, according to the study. Some teach evolution as it relates strictly to molecular biology. Others explain that students need to know evolution because it is on state tests. Finally, another group in the “cautious 60 percent” presents various positions about evolutionary processes, scientific and not, allowing for students to make up their own mind, according to the study.
This can seriously undermine students’ ability to make judgments about the world around them, said Pultzer.
“When teachers suggest that scientific conclusions are something you can determine based on your opinion, many students will simply accept the prevailing beliefs in their communities and families,” he said.
Students should be taught evolution “in a way that lets them know clearly that evolution is the dominant thought among scientists and governs the way they see the living world” from a scientific perspective, said Katie Tseng, an adjunct faculty member at the School of Education and Social Policy at Northwestern University.
Having taught in Chicago Public Schools and trained future science educators, Tseng said it’s important for students to hear other ideas.
As a teacher, Tseng said she invited proponents of intelligent design to speak to her classes after they had finished their science unit on evolution.
She said students inevitably question and doubt the theory of evolution.
“The nature of science is not to shut down ideas you don’t agree with. The nature of science is to hear them out and either accept or reject based on data,” she said. Students could “shut down to learning if there is not at least some forum for their ideas and thoughts to be explored.”
Plutzer said it makes sense to expose students to alternative theories if it serves to explain the scientific process.
However, teaching just to expose students to different theories is “more appropriate in a course on comparative religion and could include creation perspectives from all of the world religions,” he said.
Science teachers need to be well-versed in the scientific method and the processes involved in coming to a scientific theory such as evolution, the study stated. Teaching the controversy behind evolution can “undermine the legitimacy of findings that are well established” by the scientific community.
“Many teachers would do a better job if they had more command of the subject and the increased confidence that comes with expertise,” Plutzer said.
The study suggests required courses in evolution for future science teachers and refresher courses for teachers later in their careers.
Core academic standards call for schools and teachers to cover the evolutionary process and evidence for it in science class.
These guidelines “make no sense if teachers ignore them,” Plutzer said.