By the sea, by the sea, by the beautiful sea! Be sure and take one on vacation or send it to someone near the sand, pool, boat or shoreline!
Searching the beach for beautiful sea shells has been an enjoyable and fascinating leisure activity for millions of persons throughout history. Finding and keeping sea shells, with their many different intricate patterns, shapes and colors, is the first experience in keeping a collection for many us, and placing shells found at the beach up to our ears to “hear the ocean” is among our fondest childhood memories. With shorelines throughout the United States and all over the world covered with these gems of nature, it understandable why this collecting shells is such a popular hobby.
Seashells are Mollusks, Mollusca. Most Mollusks are soft fleshy slug like creatures that instead of having backbones or internal skeletons, have hard external calcium carbonate structures to help protect them from their predators. Mollusks can be found in both salt and fresh water, as well as on the land (snails). In the oceans, the mollusk’s protective structure is known as a seashell. Mollusks are an ancient group whose fossils can be traced back 600 million years. Latouchella mollusks became extinct 300 million years ago, but were the progenitors of the four main classes of mollusks, gastropods, bivalves, cephalopods and tusk shells, which all developed between 570 and 540 million years ago. The class Cephalopoda developed with straight, chambered shells about 570 million years ago and are represented today by the chambered nautilus. Gastropods evolved about 540 million years ago in many diverse shapes, but seldom growing to more than two inches long. Gastropods are the only mollusks that have successfully adapted to land. Many land snail species can survive without water in deserts for years in a state of suspended animation, called estivation. Some gastropods survive winters frozen in ice, while other species live in thermal springs exceeding 100º Fahrenheit. In the the early Cambrian period, bivalves, such as clams and oysters, developed between two tightly fitting shells. With their mobility greatly reduced, most bivalves became filter feeders, dependent upon constantly extracting the food sources found suspended in water. Today there are more species of mollusks than at anytime in history.