|
This is an excellent question of the "why is the sky blue?" variety. Fortunately, the official Conchologists of America site features a frequently asked questions page. A conchologist, by the way, is someone who studies mollusks and their shells. A mollusk is roughly defined as an animal with a soft, unsegmented body and a protective calcareous shell. Snails and clams are mollusks. So are squid and octopi, though they lack shells. Seashells are actually created by marine mollusks. As the Conchologist FAQ explains, these shells serve a variety of functions.
A mollusk that depends on camouflage to survive may have a spiny shell, in order to host "encrusting organisms" that help it blend in with its environment. Some mollusks that dig through mud for food have tapered shells to make their job easier. Mostly, though, shells serve to protect the tens of thousands of species of marine mollusks. The hues of the shell are often influenced by the diet of the mollusk, but some color pigments also serve an important structural role, helping to reinforce the shell. To sum it all up, a shell's shape, size, and color all depend on the animal that made it and the purpose it serves -- truly a case of function determining form.
|
