what animals are in the mollusca phylum

by Zack Lakin Published 3 years ago Updated 2 years ago

What animals belong to the phylum Mollusca?

The molluscs include many familiar animals, including clams, snails, slugs, and squid, as well as some less familiar animals, like tusk shells and chitons (Fig. 3.51 A). Molluscs are found in nearly all freshwater and marine environments, and some are found also on land.

What are 5 examples of Mollusca?

ExamplesClams.Mussels.Octopus.Pila ( Snail)Oyster.Cuttlefish.Squid.

What are the 7 classes of Mollusca?

The seven classes of molluscs are Gastropoda, Bivalvia, Polyplacophora, Cephalopoda, Scaphopoda, Aplacophora and Monoplacophora.

What are the 8 classes of Mollusca?

The Phylum Mollusca consist of 8 classes: 1) the Monoplacophora discovered in 1977; 2) the worm-like Aplacophora or solenogasters of the deep sea; 3) the also worm-like Caudofoveata; 4) the Polyplacophora, or chitons; 5) the Pelecypoda or bivalves; 6) the Gastropoda or snails; 7) the Scaphopoda, or tusk shells; and 8) ...

Is jellyfish a mollusk?

Jellyfish are found all over the world, from surface waters to the deep sea. Scyphozoans (the "true jellyfish") are exclusively marine, but some hydrozoans with a similar appearance live in freshwater....JellyfishPhylum:CnidariaSubphylum:MedusozoaGroups included7 more rows

What are the 4 major molluscs?

The four major groups of mollusks (phyla Mollusca) are: 1) chitons; 2) gastropods, including snails, slugs (mostly marine, but some freshwater), and nudibranches.

What are 6 mollusks examples?

clams, mussels, oysters, and scallops (class Bivalvia)ark shell (family Arcidae)cockles (family Cardiidae)coquina clam (genus Donax)gaper clams (Tresus nuttallii and Tresus capax)geoduck (Panopea generosa)jingle shells (family Anomiidae)mussels (families Mytilidae and Unionidae) ... genus Nuculana.More items...

Is an octopus a mollusc?

octopus, plural octopuses or octopi, in general, any eight-armed cephalopod (octopod) mollusk of the order Octopoda. The true octopuses are members of the genus Octopus, a large group of widely distributed shallow-water cephalopods. (See cephalopod.)

Is squid a mollusc?

The main groups of mollusc are the gastropods (snails), bivalves (cockles and mussels), and the cephalopods (squid, octopus, nautiloids and the extinct groups ammonites and belemnites).

What are the 3 main mollusks?

The three major groups of mollusks are gastropods, bivalves, and cephalopods (SEF ul o pods). The largest group is the gastropods. These are mollusks like snails and slugs that have just one shell or no shell at all.

Is a crab a mollusk?

Shrimp and crabs are not mollusks. They belong to the phylum Crustacea. Crustaceans are not true filter feeders like clams, mussels, oysters, and scallops in the phylum Mollusca, subphylum Bivalvia, and typically do not filter dinoflagellates for food.

Is Oyster a mollusk?

Bivalve mollusks (e.g., clams, oysters, mussels, scallops) have an external covering that is a two-part hinged shell that contains a soft-bodied invertebrate. A roughfile clam from the Flower Garden Bank National Marine Sanctuary—just one of many different bivalve mollusk species.

What is a mollusk?

Mollusk, any soft-bodied invertebrate of the phylum Mollusca, usually wholly or partly enclosed in a calcium carbonate shell secreted by a soft mantle covering the body. Along with the insects and vertebrates, it is one of the most diverse groups in the animal kingdom, with nearly 100,000…

What are the animals that are considered insects?

Worldwide in distribution, they include animals as diverse as sea stars, sea urchins, earthworms, sponges, jellyfish, lobsters, crabs, insects, spiders, snails,…. insect. Insect, (class Insecta or Hexapoda), any member of the largest class of the phylum Arthropoda, which is itself the largest of the animal phyla.

What is the most diverse group of animals?

mollusk . Mollusk, any soft-bodied invertebrate of the phylum Mollusca, usually wholly or partly enclosed in a calcium carbonate shell secreted by a soft mantle covering the body. Along with the insects and vertebrates, it is one of the most diverse groups in the animal kingdom, with nearly 100,000…. invertebrate.

What are the characteristics of a mollusca?

The organisms belonging to phylum Mollusca exhibit the following characteristics: They are mostly found in marine and freshwater. Very few are terrestrial and found in moist soil. They exhibit organ system level of organization. Their body has a cavity.

How to know more about mollusca?

To know more about Mollusca, keep visiting BYJU’S website or download BYJU’S app for further reference.

What is the study of mollusca called?

The animals belonging to the phylum Mollusca have soft-bodies, triploblastic and bilaterally symmetrical and coelomate. The study of Mollusca is called Malacology. They are sluggish invertebrates, with a thin fleshy envelope or mantle covering the visceral organs.

What is the body of a squid?

Their body has a cavity. The body is divided into head, visceral mass, muscular foot and mantle. The head comprises of tentacles and compound eyes. The body is covered by a calcareous shell. The muscular foot helps in locomotion. They have a well-developed digestive system, the radula is the rasping organ for feeding.

How many arms does an octopus have?

Octopus has 8 arms and contains no shell. They also possess ink glands for protection.

Why are bivalve molluscs important?

They play a very important role in the lives of humans. They are a source of jewellery as well as food . Natural pearls are formed within these molluscs. The bivalve molluscs are used as bioindicators in the marine and freshwater environments. But few of them such as snails and slugs are pests.

Where did the term "mollusca" come from?

The term Mollusca was derived from the term given by Aristotle to cuttlefish. Mollusc means soft.

What are the Characteristics of Phylum Mollusca?

Members of this phylum are commonly called soft-bodied animals since they have a soft body enclosed in a calcareous shell. The characteristics of Phylum Mollusca are listed below:

How many species of molluscs are there?

Over 160000 species have been described, of which around 128000 are living and about 35000 are recorded as fossil species. The study of molluscs is known as Malacology and the study of the molluscan shell is known as Conchology.

What phylum do snails belong to?

These snails belong to the Phylum Mollusca. Phylum Mollusca is the second most abundant phylum in the Animal Kingdom.

What are the excretory organs of molluscs?

Excretory organs are in the form of structures called organs of Bojanus. Ammonia is the chief excretory matter. The digestive tract is complete with a digestive gland or liver. In some molluscs like Pila, the buccal cavity contains a grasping organ, the radula, with transverse rows of teeth for cutting the grass.

Why do mollusks have osphradium?

Some molluscs have Osphradium for testing the chemical and physical nature of water. The sexes are separate, and fertilization is internal. They are oviparous. The development is either direct or indirect. When the development is indirect, it includes a characteristic larva, veliger, trochophore or glochidium.

How many dorsal plates are there in a shell?

Shell as 8 dorsal plates or as spicules.

How many pairs of gills are there in pallial grooves?

Five pairs of gills in pallial grooves.

What are the characteristics of a mollusc?

Many, however, occur in fresh water and some even in damp soil. ADVERTISEMENTS: 2. Body Form: The body of molluscs is un-segmented with a distinct head, muscular foot and visceral hump.

What are molluscs eyes called?

In many molluscs, eyes are present over stalks called ommatophores. Statocysts (balancing organs) may be present. Osphradium is present in some molluscs for testing chemical and physical nature of water.

How many pairs of muscles does Neopilina have?

Neopilina has 8 pairs of muscles, 5 or 6 pairs of gills, and 5 pairs of nephridia. Metameric segmentation and presence of the trochophore larva in both annelids and molluscs suggest that molluscs have descended from the annelids. Thus, the annelids are the evolutionary precursor of molluscs.

Why are molluscs asymmetrical?

In some molluscs like Pila, due to torsion (twisting) during growth, the adults become asymmetrical. 4. Shell: Shell is secreted by mantle. It is made up of calcium carbonate. Shell may be external (e.g., most of molluscs), internal (e.g., slug, cuttle fish, squid) or absent (e.g., Octopus).

What class is a cephalopod?

Class 6. Cephalopoda (Gk. kephale- head, podos- foot): Head and foot region combined and modified into a structure which has eyes and eight tentacles, hence the name cephalopod or ‘head foot’. Cephalopods are regarded at the top of invertebrates evolution in terms of learned behaviour they exihibit.

What is the dorsal cavity?

It is a thin, fleshy fold of dorsal body wall more or less covering the body. It encloses a space, which is called mantle cavity (= pallial cavity).

Where is coelom restricted?

Coelom is greatly reduced. It is restricted to pericardial cavity (space around the fieart), and to small spaces within kidneys and gonads (testes and ovaries). Spaces amongst the viscera (soft organs) contain blood and form haemocoel.

What Are Molluscs?

Molluscs are the second-largest phylum of invertebrates and the largest marine phylum, comprising 23% of all marine organisms. From the common snail and octopus to the tusk shell and cuttlefish—are all molluscs.

1. Abalone (Commonly Known as Ear Shell)

The abalone is a marine water mollusc that belongs to the genus Haliotis. It is a marine snail, and its shell has an open spiral structure. The inner layer is composed of "nacre" also known as "mother-of-pearl," which gives the shell a strong and iridescent structure.

2. Red-lined Bubble Snail

The red-lined bubble snail is a marine gastropod mollusc and belongs to the order Bullina. It is found in the sublittoral zone of the Indo-Pacific. It can reach a maximum size of 25 mm.

3. Sea Hare

Sea hares are sea snails with shells, but because of their large size and rounded body—with large rhinophores on the head—they resemble rabbits or hares. Aplysia Vaccaria, also known as the Californian black sea hare, is the world's largest living gastropod.

4. Conch

Conches are large-sized sea snails with a high spire (a part of the shell of a snail) and a noticeable siphonal canal (the shell comes to a noticeable end at both ends). They contain long eyestalks and a narrow aperture. A foot ending is present in a sickle-shaped, pointed operculum which is used for propelling forward.

5. Sea Butterfly

Sea butterflies are actually small pelagic sea snails that float and swim freely in the water. In several families, there are no shells or gills, and instead of feet, two wing-like lobes are present, which are used for slow flapping movement.

6. Reaper Cuttlefish

The Reaper cuttlefish, also known as the red cuttlefish, is a species of cuttlefish native to the southwestern Pacific Ocean. The scientific name is Sepia Mestus and it belongs to the family Sepiidae. The red body of the cuttlefish contains dark blotches and yellow coloration around the eyes.

What are the members of the phylum Mollusca?

Members of the phylum Mollusca are soft-bodied animals, such as the snail, clam, squid, oyster, and octopus. Generally, these animals live in water. Some secrete a hard shell. Each mollusk has a muscular organ called a foot that is used for gripping or creeping over surfaces. The animal has a head with a mouth; a brain or a sense organ; and groups of internal organs for circulation, excretion, respiration, and reproduction. All mollusks have a mantle, a thick fold of tissue that covers the internal organs. The space between the mantle and the body organs is called the mantle cavity.

What are the three classes of mollusca?

Three major classes make up the phylum Mollusca. The first class includes the gastropods, a group of land snails and slugs . The second class encompasses the bivalves, a group of oysters, clams, and other organisms with two shells. The third class is the cephalopods, a group of animals with numerous arms and suckers that extend from the “head foot”; octopuses and squids are in this group .

Do mollusks have a circulatory system?

Unlike the previous invertebrates presented in this chapter, mollusks have a well-developed circulatory system with a chambered heart for pumping blood. The blood passes through gills, where oxygen is obtained from water and carbon dioxide is given off. The circulatory system is said to be “open” because blood passes into open spaces at one point during its circulation.

What is the name of the mollusk?

Mollusk, also spelled mollusc, any soft-bodied invertebrate of the phylum Mollusca, usually wholly or partly enclosed in a calcium carbonate shell secreted by a soft mantle covering the body. Along with the insects and vertebrates, it is one of the most diverse groups in the animal kingdom, with nearly 100,000 (possibly as many as 150,000) ...

Where are mollusks found?

Found on rocky, sandy, and muddy substrata, mollusks burrow, crawl, become cemented to the surface, or are free-swimming. Mollusks are found worldwide, but there is a preponderance of some groups in certain areas of the world.

How big are molluscans?

Typical molluscan features have been substantially altered, or even lost, in many subgroups. Among the cephalopods the giant squids ( Architeuthis ), the largest living invertebrates, attain a body length of eight metres (more than 26 feet); with the tentacle arms extended, the total length reaches to 22 metres. Other cephalopods exceed a length of one metre. Many of the remaining molluscan classes show a large variation in size: among bivalves the giant clam ( Tridacna) ranges up to 135 centimetres (four feet) and the pen shell ( Pinna) from 40 to 80 centimetres; among gastropods the sea hares ( Aplysia) grow from 40 to 100 centimetres and the Australian trumpet, or baler ( Syrinx ), up to 60 centimetres; among placophores the gumshoe, or gumboot chiton ( Cryptochiton ), achieves a length up to 30 to 43 centimetres; and, among solenogasters, Epimenia reaches a length of 15 to 30 centimetres. Finally, gastropods of the family Entoconchidae, which are parasitic in echinoderm sea cucumbers, may reach a size of almost 1.3 metres. In contrast, there are also minute members, less than one millimetre (0.04 inch) in size, among the solenogasters and gastropods.

How big are gastropods?

Finally, gastropods of the family Entoconchidae, which are parasitic in echinoderm sea cucumbers, may reach a size of almost 1.3 metres. In contrast, there are also minute members, less than one millimetre (0.04 inch) in size, among the solenogasters and gastropods.

Why are mollusks important?

Mollusks are of general importance within food chains and as members of ecosystems. Certain species are of direct or indirect commercial and even medical importance to humans. Many gastropod species, for example, are necessary intermediate hosts for parasitic flatworms (class Trematoda, phylum Platyhelminthes), such as the species that cause schistosomiasis in humans. Most bivalves contribute to the organic turnover in the intertidal ( littoral) zones of marine and fresh water because, as filter feeders, they filter up to 40 litres (10 gallons) of water per hour. This filtering activity, however, may also seriously interfere with the various populations of invertebrate larvae ( plankton) found suspended and free-swimming in the water. One species, the zebra mussel ( Dreissena polymorpha ), is regarded as a particularly harmful exotic invader. Carried from Europe in ship ballast water, zebra mussels were taken to the Great Lakes in 1986. To date, they have caused millions of dollars in commercial damage by clogging the water pipes of power plants and cooling systems. They are driving many native freshwater bivalve species to extinction.

When were zebra mussels taken to the Great Lakes?

Carried from Europe in ship ballast water, zebra mussels were taken to the Great Lakes in 1986. To date, they have caused millions of dollars in commercial damage by clogging the water pipes of power plants and cooling systems. They are driving many native freshwater bivalve species to extinction.

Do mollusks live in air?

The mollusks have adapted to all habitats except air. Although basically marine, bivalves and gastropods include freshwater species. Gastropods have also adapted to land, with thousands of species living a fully terrestrial existence. Found on rocky, sandy, and muddy substrata, mollusks burrow, crawl, become cemented to the surface, or are free-swimming.

What glue do mussels use?

their glue is made from protein strands that can attach strongly to even teflon applications to develop aquatic glues, antifouling paints, stronger sutures

Do octopus have a large gill?

octopus and cuttlefish actual “think & plan” since the cephalopods are so active they require more oxygen than other molluscs most have 1 pr of large gills; no cilia mantle cavity expands and contracts to draw water over gills à more efficient than cilia

History of Phylum Mollusca

What Are The Characteristics of Phylum Mollusca?

Following are a few examples of the animals belonging to phylum Mollusca: Pila (Apple snail) Limax (Slug) Unio (Freshwater mussel) Turbinella (Shankha) Helix (Garden snail) Octopus (Devilfish) Loligo (Squid)