No Experience Required
First, your view of cabinet ministers is essentially wrong. Few cabinet ministers are experts on the areas they govern. They don't need to be, because their departments are staffed with experts. Their role is to make tradeoffs between different values, something they have some understanding of as politicians.
Incidentally, knowledge of the economics of R&D is probably more relevant than whether or not somebody is a scientist.
But are the best ministers specialists in their fields?
Harper's best minister is Jim Prentice. He is currently minister of the environment and was minister of industry, despite not having a background in environmental science or economics.
Chretien's best ministers were Paul Martin and John Manley. Martin was a lawyer by training, and later a businessman, but had no economics background. Despite that we was a good finance minister. John Manley was a lawyer, who also had no real econ background or IR background, yet was widely praised as industry and foreign minister.
Mulroney's best minister was Joe Clark. Joe Clark had no background in foreign policy, yet was a great external affairs minister. Where Clark did much worse was as constitutional affairs minister (although it was closer to his expertise as a lawyer).
Trudeau's best minister was Allan MacEachen. He served in almost every major role, and only had a background in economics, suitable to his finance gig.
At the provincial level, Gerard Kennedy was a popular education minister, even though he never graduated from university.
Expertise is not really a good predictor of who will be a successful cabinet minister. Indeed, often the experts have a lot invested in particular ways of doing things, and so are more dismissive of their staff.
Gordon O'Connor was a Brigadier-General, but a lousy minister of national defence. Gerry Ritz is a farmer, but has been a poor minister of agriculture.
Alfonso Gagliano's skills as an accountant came in handy when he was minister of public works, but for the wrong reasons.
Bottom line: being a government minister has more to do with reading the public and doing your homework than it does with having any sort of expertise on a given file.
Interesting point. So, I'll ask the open question - is it beneficial for Cabinet Ministers to have a background in, or knowledge of, their portfolio before taking it on?
Personally, I don't think it's essential, although I do think having an interest or fascination with the subject should be a requirement. I can't say that Veterans Affairs is really a passion of mine, so I suspect I'd be a pretty lousy minister in that portfolio. If the Minister doesn't enjoy what he or she is doing, and doesn't feel strongly about it, do you really think they'll do a good job?
There also needs to be a basic understanding of some key issues. If your foreign minister doesn't know a thing about Afghanistan or your environment minister doesn't understand the basic principles of global warming...well, that's going to be a problem.
No, I don't think understanding evolution is a prerequisite for being the Minister of Science. My only worry with Goodyear is that he may be skeptical of scientists, and may not fully appreciate the many positive benefits scientific advances can bring about. It's hard to imagine how someone like that could be an effective Cabinet Minister.
But I don't want to put words in his mouth or pre-judge him. The man may be a science camp alumni who sees just how important investments in this field are for Canada's long term success and competitiveness. There's little to indicate otherwise.