When it comes to increasing partisanship in the United States, it seems no issue is immune. And that includes evolution.

A new Pew Research Center poll shows a widening political gap over theories about how humans came to be, with Republicans growing increasingly skeptical about the idea that humans evolved over time.

Over the last four years, the percentage of Democrats who said they believe in evolution has risen by three points, from 64 percent to 67 percent. But the percentage of Republicans who believe in the theory has dropped 11 points, from 54 percent to 43 percent.