Behind the beautiful shapes and colors of seashells is the story of how a group of animals called mollusks evolved in order to survive. The wide variety of mollusks includes clams, oysters, snails, mussels, squid, and octopus. The word mollusk comes from Latin meaning "soft," a good description of the group's fleshy bodies. Of course, in an ocean filled with predators, a soft body is easily eaten. The early mollusks that happened to develop hard shells not only managed to survive but also succeeded in launching an ever-escalating 500 million year old battle between themselves and their predators. Join National Geographic as evolutionary Biologist Geerat Vermeij studies how mollusks succeeded in the ocean's arms race.
