WASHINGTON (AP) – Americans are divided over whether humans and other living things evolved over time or have existed in their present form since the beginning of time, according to a new poll.

People on both sides of that argument think students should hear about various theories, however.

Nearly two-thirds of those in a Pew Research Center poll, 64 percent, say they believe “creationism” should be taught alongside “evolution” – a finding likely to spark more controversy about what is taught in the schools.

That controversy could be related to the difficulty of measuring public sentiment about teaching evolution, creationism or the more recent concept of “intelligent design,” a Pew official said.

“We acknowledge there may be some confusion about the meaning of these terms,” said Luis Lugo, director of the Pew Forum on Religion and Public Life. But Lugo said the findings suggest widespread support for teaching students different ideas about how life began.

“What this basically tells us is that in contentious issues, many people take the default position – teach both sides and let people make up their own minds,” Lugo said.

“Intelligent design” is a movement among some scholars over the past 15 years that says Charles Darwin’s theory of evolution – that natural selection caused gradual biological changes over time – cannot fully explain either how life originated or how extremely complex life forms emerged. An undefined “intelligence” must therefore have been involved, they contend.

In the poll by the Pew Research Center, 42 percent of those surveyed held strict “creationist” views that “living things have existed in their present form since the beginning of time.” Creationism generally refers to a literal reading of the Bible’s story of the creation of man.

Almost half, 48 percent, said they believed humans have evolved over time. Some of those people, 26 percent of all those polled, said they believe evolution occurred through natural selection, and another 18 percent of all those polled, said evolution was guided by a supreme being.

Eugenie Scott, executive director for the National Center of Science Education, questioned whether the poll was a reflection of support for teaching “creationism” in school. The center supports the teaching of evolution in schools.

“What the poll reflects is the power of the idea of fairness in American culture,” she said. “We feel strongly we should always hear both sides.”

Some want to see evolution taught in a broader context. Warren Nord, a professor of philosophy at the University of North Carolina, said it’s important for students to learn about evolution in context with culture generally. “Students should understand the controversy,” Nord said. The different theories “should be addressed in science classes. All science textbooks and courses should locate them in a larger cultural conversation about how to make sense of nature.”

The poll of 2,000 adults was conducted July 7-17 and has a margin of sampling error of plus or minus 2.5 percentage points.