Threats to their survival include exploitation, pollution, habitat alteration or destruction, introduced species, and over-collecting.
After insects, molluscs are probably the most familiar invertebrate, with more than 100,000 species living and a long fossil history. Of all the invertebrates, molluscs are most valued by man; they are a major food source in many parts of the world, their shells provide a variety of products, and the diverse and beautiful forms that these may take have led to molluscs becoming important elements in the art, culture and traditions of many cultures.
Molluscs are a large and diverse group of soft-bodied unsegmented animals. Nearly 130,000 recent species are known, and some 35,000 fossil species. They include many familiar animals, like snails, clams, squid, octopii, etc, as well as others not so well known. They range in size from microscopic forms to the giant squid Architeuthis. Thought to have first appeared during earliest Cambrian period. One of the most successful forms of animal life, the molluscs have conquered almost every habitat and exist in all the oceans (from shallow tidal pools to the deepest trenches), in fresh water, and on land. The only environment they cannot cope with are very dry regions, as their moist skin is easily desiccated.
After insects, molluscs are probably the most familiar invertebrate, with more than 100,000 species living and a long fossil history. Of all the invertebrates, molluscs are most valued by man; they are a major food source in many parts of the world, their shells provide a variety of products, and the diverse and beautiful forms that these may take have led to molluscs becoming important elements in the art, culture and traditions of many cultures.