Ancient, Not Primitive
Dating back at least 425 million years ago, sharks are among the oldest surviving vertebrate groups. But as we have seen, the popular conception of sharks as creatures that have somehow sidestepped the processes of evolution and arrived in our time virtually unchanged is pure bunk. During their long evolutionary career, sharks have undergone two major adaptive radiations plus several smaller ones, the most recent of which coincided with the mammalian flowering that eventually produced ourselves. Over a time span three times as long as the reign of the dinosaurs, sharks flirted with an astonishing variety of forms and lifestyles. Not all of these evolutionary experiments were successful, but those that survived incorporated all the successful features of the past. The sharks we see today - from wobbegong to white shark - are the stripped down, fine-tuned result of hundreds of millions of years' of evolutionary tinkering. While sharks are undeniably ancient, there is nothing "primitive" about their modern descendants.