I don't think that subbie's comment can be too overemphasized. There are unanswered questions in all fields of science. A theory is not falsified just because there is a phenomenon under its purview that poses unanswered questions.
There is so much evidence in favor of the Theory of Evolution that it is not in serious doubt. Therefore, we have are led to consider two possibilities:
(1) Geckos, bombadier beetles, hummingbirds, giraffes, seahorses, and platypuses the only six specially created "kinds" among all life, or
(2) they evolved like everything else, except we just don't know the details of their evolutionary history.
Incidentally, I have already seen plausible histories of several of the mentioned species, and for the others it just isn't too hard to think of a plausible history. Try doing it yourself; the only requirement is that you develop the feature in small steps, and that each step results in improved "fitness" over the previous step.
Remember: the opposite of "this is impossible" is
not "this actually occurred"; the opposite of "this is impossible" is "this
is possible". Therefore, it is not necessary to know the actual details of the actual history to refute the argument by incredulity; all that is necessary is to explain why it is possible, to give a plausible explanation.
"We must respect the other fellow's religion, but only in the same sense and to the extent that we respect his theory that his wife is beautiful and his children smart."
-- H. L. Mencken (quoted on Panda's Thumb)