I agree that finding that half of polled students can’t identify that “human beings, as we know them today, developed from earlier species of animals” is true doesn’t imply that the other half are creationists, given that other science questions also garnered less-than-spectacular results.
However, it also doesn’t mean that all of the negative response is due to insufficient science education, nor would a general improvement in science education necessarily imply an improvement in biology, et. al, if crappyscience™ is what gets adopted be school boards, or actual science education is discouraged.
Blake Stacey has an excellent post in which he has compiled a collection of incidents of educators and others being harassed and hounded by people who didn’t like the conclusions at which science arrives.
Open your mouth about evolution around the wrong people, though, and you can find yourself harassed, ejected from your job and even beaten in the street.
Just ask these people.
The recognition that our science education needs to be improved has to be tied in with admitting that things won’t get better if we don’t actually teach science in science class.