Mollusca | Gastropods-Bivalves-Cephlapods |

Wednesday, February 20, 2019

Let's take a quick look at phylum Mollusca
Mollusks are invertebrates that are found in the ocean, in freshwater, and on land.
Almost all mollusks have these common traits.

  • A soft body and bilateral symmetry
  • An internal or external shell
  • A toothed tongue called the radula The radula is used by mollusks for feeding and is sometimes compared to a tongue. The radula is found in every class of mollusks except bivalves.
  • Mollusks have a mantle which is a covering of the visceral mass. The visceral mass contains the digestive, excretory, and reproductive organs.
  • An organized nervous system
  • A muscular foot that may be used for movement

Let's take a look at three major classes of gastropods


Gastropods have a head and a foot. Although the name "snail"  is, applied to all the members of this class, commonly this word means only those species with an external shell. Those gastropods without a shell are usually known as slugs.
Gastropods have an extraordinary diversification of habitats.
They live in gardens, woodland, deserts,  and even in the depths of the oceans. 


Bivalves are mollusks that have two shells.
Some common examples are clams, oysters, mussels, and scallops. Bivalves are found in saltwater, as well as freshwater.
They do not have a head and most are filter feeders.


Have a prominent head, body, foot and a set of arms or tentacles. Animals in this class are carnivorous predators and have beak-like jaws. All cephalopods have a very well-developed nervous system along with eyes.
Several have the ability to change colors quickly.
Examples include,octopus,squid,and cuttlefish
The cuttlefish is famous for having the ability to change its color to blend into almost any background. 


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