Table of Contents
Mollusca
Mollusca is a large and diverse phylum of invertebrate animals. It includes snails, clams, octopuses, and squids. Mollusks have a soft body, and their most conspicuous feature is a hard shell. Most mollusks are marine animals, but some live in freshwater or on land.
Mollusca Examples:
Mollusks are a large group of invertebrate animals that live in water. They are characterized by a soft body, and a mantle that covers the body and secretes a shell. Mollusks include clams, oysters, snails, and squid.
Mollusca Characteristics
The Mollusca are a large phylum of invertebrate animals. They are characterized by a soft body, and a lack of a backbone. Mollusks have a wide variety of body shapes, and include snails, clams, and octopuses. They are usually hermaphroditic, and use a radula to scrape food from surfaces. Mollusks have a simple nervous system, and a closed circulatory system.
Classification of Mollusca
Mollusca is a taxonomic class of invertebrate animals that includes snails, clams, and octopuses. Mollusks are distinguished by their soft bodies, and the presence of a mantle cavity, a fold of tissue that surrounds the gills. Mollusks have a well-developed nervous system, and their eyes are well-developed. They also possess a radula, a toothed tongue that is used for scraping food from surfaces. Mollusks are divided into eight orders: gastropods, bivalves, cephalopods, scaphopods, monopods, tubularians, aplacophorans, and solenogasters.
Class Aplacophora
The class Aplacophora contains a small, diverse group of mollusks that lack a shell. These animals are sometimes called “worm-snails” because of their long, slender body shape. Aplacophorans live in marine environments and eat a variety of things, including algae, bacteria, and pieces of dead animals.
Class Monoplacophora
Class Monoplacophora contains the mollusks that have a single shell. This shell is made of calcium carbonate and is secreted by the mantle. The class includes the chitons, which are marine animals that can be found on the ocean floor.
Class Polyplacophora
There are around 800 species of mollusks in the class Polyplacophora, which is Latin for “many plates.” These creatures are easily identified by their hard, shell-like bodies, which are made up of eight separate plates. The plates are attached to the animal’s dorsal (back) surface and are used for protection and movement. Polyplacophorans are mostly marine creatures, but a few species can be found in brackish water and a few others in fresh water.
Class Bivalvia
Class Bivalvia is a class of clams, mussels, and other bivalve mollusks.
Bivalvia includes the following groups:
- Lamellibranchia (clams, mussels, oysters, and other bivalves that have a gill)
- Pelecypoda (clams, mussels, and other bivalves that do not have a gill)
- Mytiloida (mussels)
- Arcidae (scallops)
- Pectinidae (jellyfish)
- Anomiidae (winged oysters)
- Unionidae (freshwater mussels)
- Ostreidae (oysters)
- Dreissenidae (zebra mussels)
- Sphaeriidae (clams)
- Cyclostomata (freshwater mussels)
Class Gastropoda
Gastropods are a group of marine and freshwater mollusks that have a single, unsegmented stomach. They are the most diverse and successful group of mollusks, with about 85,000 species.
Class Cephalopoda
Cephalopods are a class of mollusks that includes octopuses, squid, and cuttlefish. These animals are noted for their large, complex brains, and their ability to change color and texture to match their surroundings. Cephalopods are also among the fastest-moving invertebrates, and are able to jet through the water by squirting water out of a siphon.
Class Scaphopoda
- Class Cephalopoda
- Class Gastropoda
- Class Bivalvia
- Class Polyplacophora
- Class Monoplacophora
Economic Importance of Mollusca
Mollusks have a wide variety of shapes and sizes, and can be found in both salt and fresh water. They are an important part of the food chain, and are eaten by many different animals. Some mollusks, such as oysters, are also important sources of food for humans.
Key Points
- Mollusca is a large and diverse phylum of invertebrate animals.
- Mollusks have a soft body, and most species have a shell.
- Mollusks are found in a variety of habitats, and there are many different types of mollusks.
- Mollusks are important in the marine environment, and some species are also important in the freshwater and terrestrial environments.
- Mollusks have a wide variety of feeding habits, and many are important in the human food chain.
- Mollusks are important in biomedical research, and they are also used in other commercial applications.
- Mollusks are important in the study of evolution, and they play a significant role in the ecology of aquatic and terrestrial ecosystems.
