Molluses

= Mollusks have been on earth for over 416 million years. They started to evolve in the Devonian period. They were very plentiful in the Devonian, and basically the rest of the Paleozoic Era. Mollusks started to decrease at the start of the dinosaurs, and at the end of the Cretaceous Period, ammonites became extinct. This left gastropods and bivalves to rule the seas. The mollusks never quite rose up to their great surge in the Paleozoic Era ever again. The mollusk family is still alive today, inhabiting oceans, lakes, and ponds. They have weak, unsegmented bodies with distinct symmetry. Some ask what the difference between brachiopods and mollusks is and the answer is this. Brachiopods have assymetrical shells while mollusks have symmetrical ones. Mollusks are benthic feeders, which means they were seafloor organisms. Mollusks filter-feed with a mouth called a radula and have a pedicle for attaching themselves to the seafloor. =