One third of Americans utterly reject the theory of evolution and believe instead that humans "have existed in their present form since the beginning of time," a new survey has found.
About a quarter of Americans believe that evolution was guided by God while only 32 percent of those surveyed believe that evolution is due to "natural processes such as natural selection," the Pew Research Center found.
The broad results were little changed from a similar survey in 2009, but Pew found a drastically widening gap along party lines.
Some 54 percent of Republicans and 64 percent of Democrats said they believed in evolution in 2009.
That ten-point gap more than doubled in the latest survey, which found that only 43 percent of Republicans believe in evolution while 67 percent of Democrats said humans have evolved over time.
The views of political independents were essentially unchanged, with 65 percent believing in evolution.
Evolution has long been a political issue in the United States, where science classes are a battleground between advocates of non-religious teachings in public schools and conservative Christians who push for curriculum that includes creationism or "intelligent design."
The debate has heated up in recent years as the so-called "culture wars" have reignited amid a deepening partisan divide.
Differences in the racial, ethnic and religious composition of the Democrats and Republicans surveyed "do not wholly explain partisan differences in beliefs about evolution," Pew said.
"Indeed, the partisan differences remain even when taking these other characteristics into account," the non-partisan research group said.
However, it did find strong differences among religious groups.
Two thirds of white evangelical Protestants believe God created humans in their present form while 78 percent of white "mainline" Protestants believe in evolution. Half of black Protestants believe God devised humans as they exist today.
Nearly seven in ten white non-Hispanic Catholics and 53 percent of Hispanic Catholics believe in evolution.
Meanwhile, three out of four religiously unaffiliated respondents believe in evolution and just 13 percent of them believe evolution was guided by a "supreme being."
The results released Monday were drawn from a telephone survey of 1,983 adults conducted March 21 through April 8 that has a margin of error of three percent.
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