Interesting Facts about Mollusks
Before we get into facts about mollusks, we wanted to first offer an introduction as to what mollusks are. Sometimes spelled “mollusks”, the official name of this invertebrate is Phylum Mollusca. Within this family of invertebrates are several other sea animals to include octopus, cuttlefish, squid, snails, slugs, sea hares, clams, mussels, nudibranchs, scallops, oysters, and others. In fact, experts believe that more than 160,000 different species of mollusks exists. Because of this, mollusks are the second largest phylum in the world.
Below, we have provided some common, as well as interesting facts about mollusks:
- Today, eight distinct groups of mollusks exist. Shaped similar to a worm and without feet or shells, they burrow deep into deep waters of the ocean floor
- Many types of mollusks are actually quite small, measuring just two inches long
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One particular class of mollusk called Bivalves are both fresh and saltwater creatures with a unique shell featuring two valves that hinge to the creature’s back
- For mollusks in the Cephalopods class, the creature has bilateral symmetry and a lost or internalized shell
- Of all classes, the Gastropod is by far the most diverse. This class has 60,000 different species and is capable of living in fresh and saltwater, as well as terrestrial habitats.
- Regarding physical characteristics, mollusks are made with two parts, a head-foot and a visceral mass. As a part of the head-foot portion of the mollusk is an anterior head with eyes, mouth, radula, and sensory, as well as nervous structures. For the foot, it is elongated and used to attach to different surfaces to move from one location to another. Then for the visceral mass of the mollusk, it sits atop the head-foot and this is where all the mollusk’s internal organs are located.
- One of the more interesting facts about mollusks is that it has a mantle that when threatened, a hard shell is secreted that serves as a protective covering over the visceral mass where all the internal organs are located. This shell consists of three layers. On the inside is the nacreous layer, the prismatic layer is in the middle, and on the outside, the periostracum. In addition to keeping the mollusk safe from predators, this shell also provides a shield against some of the more challenging environmental conditions.
- Another one of the interesting facts about mollusks is that in some species there is no head or shell
- One thing that most people do not realize is that both the giant clam and giant squid are mollusks and considered the largest of all mollusks in the world.
- Not only are mollusks found in the ocean but they can also be found on land
- The Cephalopod class of mollusks is quite intriguing. This particular mollusk is very shy, it moves fast going backwards but slow in other directions, and does not respond to sound although it does respond to sounds at extremely low frequencies.
- Among the facts about mollusks, one that people find amazing is that many species of land snails are so strong they can actually lift 10 times their own body weight when on a vertical surface.
- The last of the facts about mollusks we wanted to offer is that of the 160,000 known species, 128,000 are still living. The remaining 35,000 species are fossils.