What are mollusks physical characteristics?

Characteristic Features of Phylum Mollusca

• They are bilaterally symmetrical.
• They are triploblastic, which three layers.
• They show organ system grade of organisation.
• The body is soft and unsegmented.
• Body is divisible into three regions – head, a visceral mass, and ventral foot.
• Body is covered by a mantle and shell.

What are main characteristics of Mollusca?

The three most universal features defining modern molluscs are a mantle with a significant cavity used for breathing and excretion, the presence of a radula (except for bivalves), and the structure of the nervous system.

How does mollusks get water?

In many bivalves and snails, and in cephalopods, part of the mantle is modified into a siphon, which can be used to pump water through the mantle cavity for respiration, feeding and/or jet propulsion. Freshwater and marine mollusks have gills (called ctenidia) for respiration, located in the mantle cavity.

What are distinctive features of mollusks?

Mollusks have a hard outer shell. There is a layer of tissue called the mantle between the shell and the body. Most mollusks have tentacles for feeding and sensing, and many have a muscular foot. Mollusks also have a coelom, a complete digestive system, and specialized organs for excretion.

Do mollusks have lungs?

Mollusks have a muscular foot, which is used for locomotion and anchorage, and varies in shape and function, depending on the type of mollusk under study. Mollusk species that are exclusively aquatic have gills for respiration, whereas some terrestrial species have lungs for respiration.

Can mollusks survive out of water?

Water mollusca prove that statement. At first sight, they are absolutely unable to live without water, as they consist almost totally from water. However, this is only at first sight.

What is the meaning of Mollusca?

: a large phylum of invertebrate animals (as snails, clams, and mussels) that have a soft unsegmented body lacking segmented appendages and commonly protected by a calcareous shell.

What are the 6 classes of Mollusca?

Mollusks can be segregated into seven classes: Aplacophora, Monoplacophora, Polyplacophora, Bivalvia, Gastropoda, Cephalopoda, and Scaphopoda. These classes are distinguished by, among other criteria, the presence and types of shells they possess.

Are there any molluscs that live in water?

This article is about freshwater Mollusca in general; for information on one particular family of freshwater molluscs, please follow the appropriate links in the lists below. The two major classes of molluscs have representatives in freshwater: the gastropods (snails) and the bivalves (freshwater mussels and clams .)

Which is the best description of a mollusc?

1. Definition of Molluscs: Phylum Mollusca is a group of invertebrates which has fascinated man from the dawn of civili­zation. It is a major group in the animal kingdom as regards the number which occu­pies next to arthropods.

What are the characters of the phylum Mollusca?

In this article we will discuss about the general characters and classification of Phylum Mollusca. 1. Habitat: They are mostly marine. Many, however, occur in fresh water and some even in damp soil. 2. Body Form: The body of molluscs is un-segmented with a distinct head, muscular foot and visceral hump. Neopilina is a segmented mollusc.

Are there any molluscs that do not look alike?

A slug, a snail, a clam, and a squid do not look alike, but they are all molluscs. Although there is no single feature that all molluscs possess, three features are so common in molluscs that they are used to distinguish them from organisms in other phyla: