An important aspect of science is being open to and even seeking out that which might disprove your theory.

the mechanisms described by the theory of evolution are undeniable, what could be debatable, although I personally am quite satisfied with the theory of evolution to explaining the diversity of life, is that there might be other mechanisms involved such as involvement of extraterrestrial intelligence, God, or other mechanisms that we haven't figured out yet. At this point it is understandable that science has not given any serious consideration to these elements because of Occam's razor principle which require that a phenomenon be explained using the simplest explanation. If diversity can be explained without the use of gods or aliens, then to follow the scientific method we must do so.