What they are
Snails, Slugs, Limpets, Sea Slugs, Whelks, Conchs
Morphology
Gastropods are another type of mollusk. They are also the most diverse group, comprising between 40,000 and 100,000 species, nearly 80% of the entire Mollusca phylum. Most gastropods have a shell that is outside of their body, symmetrically coiled and unchambered. They also have a distinct head, which can be retracted into the shell in case of danger in some species. Like all other mollusks, gastropods have a foot, which in their case is used for movement. This foot is located underneath the entire length of the body, allowing the gastropod to slowly creep along the surface. Some gastropods can even use their foot as a makeshift sail and ride the currents for short distances, especially near the shore where waves break.
Ecology
Gastropods live both in terrestrial (land) and marine environments, although the vast majority live in the waters of the world.
Gastropods have a variety of different diets. Some species, like abalones, scrape algae from rocks along the ocean floor. Others may cling to large marine plants, like kelp, and feed off of those. Still, others scavenge along the sea floor for bits of food. Some may just sit on a rock and filter feed, flushing water through a membrane to catch small bits of food like a net.
Some gastropods are active predators. Some can drill through the toughest of shells, like pelecypods (bivalves) and echinoids, to get to the creature inside. Some gastropods, like the cone snail, use a poisoned barb like a harpoon to catch prey.