A similar example would be the blind fish that inhabit caves. Here mutations have eliminated organs which have no use in the dark. These changes are, indeed, significant, but notice that they involve the loss of existing structures. No one has ever seen a species undergo mutations that produce brand-new wings or eyes. There is, however, another process by which individuals can vary.
Recombination explains why children look different from their parents.
This shuffling of the genes can produce superior combinations of different genes. However, because we see that mutations are incapable of supplying useful variation, the useful genes that are there to be shuffled must have been created at the beginning. We have mutation and recombination as the processes by which individuals can change. But the history of life is primarily the story of populations, not individuals. Charles Darwin correctly described natural selection as a powerful process in the history of populations.