Phylum: Mollusca
The phylum mollusks comprises over 50+ thousand species and can be characterized into four different classes; Polyplacophora, Gastropoda, Bivalvia and Cephalopoda. Common members of the Mollusk phylum are clams, snails, quids, octopi, and oysters.
The phylum mollusks comprises over 50+ thousand species and can be characterized into four different classes; Polyplacophora, Gastropoda, Bivalvia and Cephalopoda. Common members of the Mollusk phylum are clams, snails, quids, octopi, and oysters.
Between all the mollusk class types there are morphological similarities such as an anterior head, a soft unsegmented body and mantle tissues. Some species of mollusks's mantle tissues secrete calcium carbonate that give rise to a hard shell, a form of protection against predators. Contrary to shelled mollusks, species such as slugs and octopuses which lack a shell utilize mantle tissue for respiration. Furthermore, mollusks utilize a mantle cavity which houses their respiratory organ and make use of a radula for gathering foods. Moreover, these organisms contain a ventral foot used for locomotion and have a dorsal visceral mass that houses the digestive, circulatory, reproductive, osmoregulatory, excretory, and other systems.
Image by Sheila Brown, click here to see original.
The habitats of mollusks ranges from the marine life in freshwater's lakes, oceans tidal pools to deep sea and even in terrestrial homes like gardens and shores. As some mollusks are native to their environments others are pests such as