I suppose there are bigger things for me to be concerned about; as an atheist, I find it deeply disturbing that more than 90% of the world disagrees with me. But in many cases imaginary friends seem to be harmless. The considerably smaller number of people who believe in creationism or "intelligent design", the new trendy version of creationism, worry me a lot more.
In general, I have a naive faith in the Humean, and not only Humean of course, notion that rational people should proportion their belief to the evidence. Here the history of evolutionary theory seems to tell a very clear story.
Hume himself trifles with something like an evolutionary theory in his Dialogues Concerning Natural Religion, pointing out that in a universe where randomness reigned, anything able to sustain itself would likely come to be, and be perceived as, what's normal. But, of course, theories of evolution were not to get their best support for another century.
Darwin rested his assertion that evolution must account for the diversity of species that we observe primarily on the basis of the geographical distribution of species, my title for this post. I have certainly never seen an argument from any creationist or intelligent design theorist to explain why God would have wanted the exact distribution of species we see in, say, Madagascar, or of course Darwin's own example of the Galapagos islands.
Because the geographical distribution of species was utterly incomprehensible on any theory other than some kind of evolution, Darwin was sure that evolution had to be the story. Never mind that in his time there was no account of how parents could pass on traits to their descendants in the way that evolution required; he was sure, on the basis of his data, that it had to happen somehow.
Indeed, the data was quite overwhelming. But we modern people don't need to rely on that. Watson and Crick, almost a century after Darwin, showed how traits do get passed on from parents to their children via DNA. This process of passing on DNA ends up being exactly what Darwinian theory requires; it resolves all of the difficulties that Darwin himself was unable to cope with. Darwin's conviction that something must do what evolution requires has been incredibly forcefully vindicated.
So modern opponents of evolution are opposing not only the (utterly overwhelming) evidence Darwin himself appealed to, but also the (even more decisive) evidence of subsequent generations of biologists and biochemists. I suppose I am an outsider, as a philosopher, but I can't help but agree with those who equate the rejection of evolution with the rejection of heliocentrism or gravity.