It is a bit of a worrying development, because science hasn't traditionally been a strong point of partisan differentiation across the board. There is a long history of Christian conservatives disliking evolution, but that specific controversy tended to stay fairly isolated, and didn't become a general anti-science position. If anything, conservatives have at various times been big promoters of certain kinds of science (nuclear research, genetically modified crops, etc.), and each party confined its objections to a few issues, and mostly on the fringes of the party (e.g. the Christian wing on one side, and the new-age/hippie wing on the other).

If I had to guess what's driving this, it'd be a mixture of:

1) ascendancy of a more "movement conservative" wing of the Republican party, displacing the more pro-science business-and-defense establishment; and

2) the ideologically objectionable area has expanded from evolution to include stem cells and climate change, and once you get to three different things you have a list, and then people start perceiving it as a pattern.

I must say that I was pretty surprised at some of the open attacks on science, though, like the calls to cut the NSF's budget, and people like Eric Cantor going on TV to attack specific computer scientists by name (while misrepresenting their research). I didn't realize that the National Science Foundation now has the status of something like NPR among the conservative base.