Anatomy: Form and Function

Suddenly and without warning, the peaceful summer afternoon was fractured. Clanging bells and bullhorns blared the awful news: Shark Alert! Shark Alert! Instantly, thousands of waders and swimmers dashed in desperation for the safe solidity of the beach. For all their splashing, screaming and yelling, none of them seemed able to move remotely fast enough. Those fortunate to be in water waist-deep or shallower tried to run, but the viscous medium tugged at and restrained them like legions of steely hands. Even the best of swimmers clawed violently at the water, making relatively little progress. As they neared the shallows, some altruistic souls nabbed children as they fought their way to the beach, plucking them from harm's way like so much wet laundry. Others in sheer, unreasoning panic simply plowed over or through anyone in their way, the salt water stinging their wide-open eyes, fixed on the so-near-and-yet-so-far beach. The cool, undulating liquid that mere moments before seemed so welcoming had become their enemy. When the last of the stampeding masses had collapsed on the sand, gasping uncontrolledly and clutching their loved ones, all eyes turned seaward. There seeming to hover in the surf was a blade-like, triangular fin. Beneath it, clearly visible, was the dark shadow of a shark perhaps 5 feet (1.5 metres) long. In stark contrast to the frightened primates, the fish slipped through the water with the ease and grace of a magician's silk scarf. Apparently disinterested in the turmoil it had inadvertently caused, the shark turned and headed for deeper water to continue hunting small schooling fishes in a more peaceful setting. As it departed, the shark never altered its fluid movements or languid pace.

Form and function are inextricably linked. One influences the other as surely and intimately as do life and death. Yet form and function are rarely static. In human technologies, changes in desired features or production costs often provoke modifications in design or material. Similarly, in living things form and function can be modified through the processes of evolution. But the degree to which biological form and function can be modified has firm limits. The Great White Shark (Carcharodon carcharias) as we see it today represents a dynamic compromise between inherited potential and environmental opportunity. It is a compromise many millennia in the making, tested on the anvil of natural selection and tempered by functional plasticity. All of the White Shark's strengths and vulnerabilities flow from its biological compromises. Despite the Great White's infamy, this near-legendary creature is no more or less than the sum of its parts. Everything that the White Shark is results from the complex and subtle ways in which its component parts work together. That the White Shark is such a remarkably spare and efficient package of muscle, cartilage, organs, and instincts is testimonial to the creative genius of natural selection. Our own cleverness has yet to come close to matching the feats of engineering prowess made flesh in the Great White Shark. Perhaps we simply need a few million years' more time to refine our nascent tinkering abilities.

 

ReefQuest Centre for Shark Research
Text and illustrations R. Aidan Martin
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