February 12 will mark the 200th anniversary of the birth of Charles Darwin, the British naturalist who developed the theory of evolution through natural selection. Darwin published his treatise on evolution, On the Origin of Species by Means of Natural Selection, nearly 150 years ago. Darwin's theory was controversial from the outset, and remains so among the public in his home country as well as in the U.S. and elsewhere.
Opinion polls over the past two decades have found the American public deeply divided in its beliefs about the origins and development of life on earth. Surveys are fairly consistent in their estimates of how many Americans believe in evolution or creationism. Approximately 40%-50% of the public accepts a biblical creationist account of the origins of life, while comparable or slightly larger numbers accept the idea that humans evolved over time. The wording of survey questions generally makes little systematic difference in this division of opinion, and there has been little change in the percentage of the public who reject the idea of evolution.
Opinions on the theory of "intelligent design," however, are far more complex, making it difficult to determine how many Americans subscribe to this view of life's origins. In part, this reflects the public's lack of familiarity with the concept of intelligent design, which holds that Darwin's theory of natural selection is inadequate in explaining the development of complex life forms. A Gallup survey in August of 2005 found that fewer than half of Americans were familiar with the term. Moreover, because the concept involves sensitive matters of faith and science, questions that attempt to indirectly measure support for intelligent design produce divergent results.
Read the full report On Darwin's 200th Birthday, Americans Still Divided About Evolution on the Pew Research Center's Web site.