We know that mutation can be, more often than not, a reason to not function normally and die, but sometimes it can be a way to develop new, successful species. To see evolution at work we only have to look at the Whitenose shark (Nasolamia velox).
See, the Whitenose shark differs from any other requiem sharks in matters of cranial and rostral characteristics so much that is has got its own genus, but all other characteristics are so much like that of the Blacknose shark that scientists began to speculate.
There is this deformation called cyclopia (named after the Greek myth cyclops which is a giant with an eye on its forehead), caused by genetic mutations (or toxins during pregnancy) in mammals and humans (Don’t look at pictures. Seriously, don’t. Look here instead.). Well, incipient cyclopia could explain the differences – so it seems that the Whitenose shark developed from the Blacknose shark, or better ancestors of the Whitenose shark mutated from ancestors of the Blacknose shark, a long time ago. This must have happened before the Isthmus of Panama separated the Pacific and Atlantic oceans, since now the Blacknose shark inhabits only the tropical western Atlantic and the Whitenose shark only the tropical eastern Pacific (so it is an example of Plate tectonics as well).
Like other requiem sharks, Whitenose sharks are caught by commercial and artisanal fisheries for their meat and fins.