While every effort has been made to provide the most reliable and uptodate information available, ultimate legal requirements with respect to species are contained in. Mollusca are the second largest animal phylum on earth after arthropods. What are the four most common and diverse classes of molluscs. Some people use the term mollusk for a member of phylum mollusca, whereas others use the term mollusc. In this article we will discuss about phylum mollusca. Members of the phylum mollusca are softbodied animals, such as the snail, clam, squid, oyster, and octopus. Download objective type questions of phylum mollusca pdf visit our pdf store. Phylum mollusca has been classified differently by different authors depending upon the characters of foot, mantle, shell, muscles, radula, nervous system and respiratory organs. Many organisms belonging to this phylum have a calciferous shell. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Classification of mollusca april, 97 1 victor millard a classification of the living mollusca which was compiled by kay cunningham vaught and published by american malacologists, inc melbourne, florida 32902, usa in 1989 was used as the basis for this compilation. 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 described species. Each mollusk has a muscular organ called a foot that is used for gripping or creeping over surfaces.
Morphological hypotheses generally placed the caudofoveata and solenogastres as plesiomorphic based on their simple wormlike body plan and lack of a shell kocot et al. Phylum mollusca bio 2215 oklahoma city community college dennis anderson phylum mollusca numbers of species molluscs 50,000 100,000 living species 35,000 extinct species largest pounds 80% less than 5 cm soft body most have a shell most marine snails terrestrial most habitat phylum mollusca ventral foot locomotion mantle encloses mantle cavity shell radula. Phylum mollusca the mollusca include chitons, clams, oysters, snails, slugs, squids, nautilus and octopuses. General characteristics of phylum mollusca microbiology notes. Mollusk, also spelled mollusc, any softbodied invertebrate of the phylum mollusca, usually wholly or partly enclosed in a calcium carbonate shell secreted by a soft mantle covering the body. The molluscs first appeared during the cambrian period of the evolutionary calendar. The animals in phylum mollusca all have bilateral symmetry.
Some species have radula which are part of the digestive system. However, it is not a legal authority for statutory or regulatory purposes. The phylum mollusca is the secondlargest animal phylum, with over 100,000 species. These characteristic features are not so easy to identify by the nonexpert. Mollusca phylum mollusca includes snails and slugs, oysters and clams, and octopuses and squids most molluscs are marine, though some inhabit fresh water and some are terrestrial molluscs are softbodied animals, most are protected by a hard shell most molluscs have separate sexes with gonads located in the visceral mass. The heart is key to keep the blood pressure regulated. The scientific study of molluscs is known as malacology. Dec 10, 2015 general characteristics of phylum mollusca mollusca molluscus soft bodies study of mollusca is called malacology. The group is extremely diverse and includes such well known forms as the squid, octopus, slugs, snails and oysters. The group has members that can appear very different to each other, though they do have fundamental features in common. Along with the insects and vertebrates, it is one of the most diverse groups in the animal kingdom, with nearly 100,000 possibly. Mollusks animals of the phylum mollusca labeling page. Start studying characteristics of phylum mollusca diaz. They are characterized by soft, unsegmented bodies and have bilateral symmetry.
In this article we will discuss about the general characters and classification of phylum mollusca. Phylum mollusca is a very diverse 85,000 species group of mostly marine species. The animals within phylum mollusca have three body layers. General characteristics of phylum mollusca mollusca molluscus soft bodies study of mollusca is called malacology. Phylum mollusca, contains 7580% of all animals in phylum. The body of molluscs is unsegmented with a distinct head, muscular foot and visceral hump. The organisms belonging to phylum mollusca exhibit the following characteristics. Mollusk, any softbodied invertebrate of the phylum mollusca, usually wholly or partly enclosed in a calcium carbonate shell secreted by a soft mantle covering the body. Animals in phylum mollusca have an open circulatory system, but also often have a heart that pumps blood. Ruppert and barnes 1994, meglitsch and schram 1991 divided molusca into 7 classes, while parker and haswell 1972, morton and yonge 1964 have clubbed class.
It includes such familiar organisms as snails, octopuses, squid, clams, scallops, oysters, and chitons. Molluscs phylum mollusca are actually the largest marine phylum, although many do live on land. Molluscs are found in nearly all freshwater and marine. While it is not so easy to see why some very different members are all molluscs, there are subgroups which are. Animals of the phylum mollusca labeling page exploring nature educational. This lesson is intended to introduce the phylum mollusca and to go over its general physical characteristics. Mollusca is one of the most diverse groups of animals on the planet, with at least 50,000 living species and more likely around 200,000. 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. Phylum mollusca objective type questions pdf download. Structure soft bodied animals name from latin word mollus meaning soft most are protected by a hard shell made of calcium carbonate have a reduced internal cell or have lost the shell completely during evolution. Shell microstructures in early cambrian molluscs pdf. The world mollusca has its root in the latin word molluscus meaning thin shelled which in turn is derived from. Members of this phylum have soft, unsegmentated bodies usually enclosed, wholly or partly, in a shell composed of calcium carbonate.
The number of valid recent species is currently estimated around 50,000 to 55,000 marine, 25,000 to 30,000 terrestrial and. Brusca and others published phylum mollusca find, read and cite all the research you need on researchgate. The animals of this phylum are softbodied, nonmetameric, triploblastic coelomates and fundamentally bilaterally symmetrical invertebrates with. To value these shall animals their classification anatomy and physiological aspects of various classgenus are described with important biological systems like digestive, respiratory, circulatory, excretory, sense organs and reproductive etc. Mollusca is the secondlargest phylum of invertebrate animals after the arthropoda.
Phylum mollusca characteristics, classification and examples. The references in that work have not been transferred to this one. Itis taxonomy is based on the latest scientific consensus available, and is provided as a general reference source for interested parties. A mollusc has a muscular foot, a mantle which can harden, creating a shell, and visceral mass. Phylum mollusca mcq multiple choice question and answer phylum mollusca mcq with detailed explanation for interview, entrance and competitive exams. The proportion of undescribed species is very high. The phylum mollusca also includes lesser known forms such as the chitons, tusk shells, solenogasters, among others. Most species use a tongue like organ called a radula when.
The phylum also provides some of the most familiar animals, such as snails, clams, mussels, squids, and octopus which, like the arthropods, are well known because theyre good to eat. The last 360 degrees of the coiled shell is called the body whorl and is the last whorl of the tube that does not have the shell coiled completely around it. They can be found in terrestrial regions as well as in the depths of the seas. True coelomate unsegmented soft bodied animalsmollusca study of mollusca malacology second largest phylum mollusca study of molluscan shells choncology jhonson created the name mollusca for cephalopods and barnacles the classification which was revised and first to include modem views was published by cuvier. In any case, both terms are pronounced the same way. The number of fossil species is estimated between 60,000 and 100,000 additional species. Also rivals arthropods in terms of ecological success. Mollusks animals of the phylum mollusca labeling page logged in as bingbot click here to login. This book has informations about phylum mollusca which has great potential in aquatic resources. The phylum mollusca is the second largest in the animal kingdom including about 100,000 living species and with a long fossil record of some 35,000 more. Phylum mollusca characteristics, classification, examples. The bodies are generally very soft and are covered by the hard exoskeleton. The molluscs americans spell it as mollusks constitute one of.
Freshwater and amphibious gastropods may be found in any temporary or permanent aquatic habitats, except phytotelmata. Depending on the author, family, genus, and species definitions and numbers will vary greatly. Many, however, occur in fresh water and some even in damp soil. Molluscabase is a taxonomically oriented database which aims to provide an authoritative, permanently updated account of all molluscan species. The latter, because it is more like the spelling of the formal name of the phylum, is easier to remember. Mollusks animals of the phylum mollusca labeling page exploring nature educational resource 20052020. Clams have a muscular foot that they use for movement if they. The word mollusc comes from the latin word mollis, which means soft. Phylum mollusca bio 2215 oklahoma city community college dennis anderson phylum mollusca numbers of species molluscs 50,000 100,000 living species 35,000 extinct species largest pounds 80% less than 5 cm soft body most have a shell most marine snails terrestrial most habitat phylum mollusca ventral foot locomotion mantle encloses mantle cavity shell radula coelom eucoelomate. The term mollusca was first applied by aristotle to cuttle fish.
They also have a tonguelike organ called the radula. Around 85,000 extant species of molluscs are recognized. Mollusca is the second largest phylum of invertebrate animals. Relationships of mollusca evolutionary hypotheses for the major groups of molluscs are controversial largely because of the extreme diversity in the phylum. Members of this phylum have soft, unsegmentated bodies usually enclosed.
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