1. (used with a sing. verb) A theory that explains the global distribution of geological phenomena such as seismicity, volcanism, continental drift, and mountain building in terms of the formation, destruction, movement, and interaction of the earth's lithospheric plates. 2. (used with a sing. or pl. verb) The dynamics of plate movement.
Despite the fact that mollusks are very susceptible to changes in their environment because of their permeable skin and soft body (often with an exoskeleton in the form of a shell), they have adapted to all of the main environments of our planetâmarine, freshwater, and terrestrial. With 41% of the 736 documented extinctions of all animal species, the number of mollusks exceeds that of any other major taxonomic group 3. 2  Most documented endangered mollusk species are non marine (they live in freshwater or terrestrial environments) 5.
Mollusks. Mollusks comprise a group of soft-bodied animals that includes snails, clams, and sea slugs. The most common characteristic of most mollusks is their shell. One of the largest groups, the snails, is renowned for their shells. Snails are univalves, which means they have one shell.And it is this shell that for many people is the epitome of the ocean.he most common characteristic of most mollusks is their shell. One of the largest groups, the snails, is renowned for their shells. Snails are univalves, which means they have one shell. And it is this shell that for many people is the epitome of the ocean.