Mollusca

Mollusks are invertebrate animals with unique characteristics, whose closest relatives include snails and slugs. They have soft bodies with a mantle that often secretes a shell from calcium carbonate deposits in their tissues. Mollusks are found all over the world, living on land or in water. Although there are hundreds of different types of mollusk, there are four main groups: gastropods (slugs and snails), bivalves (clams, oysters), cephalopods (squids and octopuses), and scaphopods (tusk shells). This article will discuss 9 unique features that define these interesting creatures. What is a characteristic vs trait vs adaptation? Characteristic All living things have characteristics. Characteristics are fundamental features, or qualities, of an organism. A trait is a characteristic of an organism that can have different visible, or phenotypic expressions, as well as be influenced in some cases by the environment. Adaptation Adaptations are features in an animal that arise as a result of natural selection. A good example of this is eye color. The presence of eye color is the character, the noticeable feature. Trait The trait is which eye color a person expresses. An example of an adaptation would be a species that selected for the brown eye color trait because blue eye color was too noticeable by predators. In this case, brown eye color would become the only eye color over several generations in said population and be an adaptation of this trait. 9 Characteristics of mollu...

Mollusca 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. The term Mollusca was derived from the term given by Aristotle to cuttlefish. Mollusc means soft. These organisms are found in the terrestrial as well as in deep seas. Their size ranges from microscopic organisms to organisms 20 metres long. 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. Mollusca Characteristics 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. • 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. • • The blood circulates through the open circulatory system. • They have a pair of metanephrid...

By the end of this section, you will be able to: • Describe the unique anatomical features of mollusks • Describe the features of an animal classified in phylum Annelida The mollusks are a diverse group (85,000 described species) of mostly marine species. They have a variety of forms, ranging from large predatory squid and octopus, some of which show a high degree of intelligence, to small grazing forms with elaborately sculpted and colored shells. The annelids traditionally include the oligochaetes, which include the earthworms and leeches, the polychaetes, which are a marine group, and two other smaller classes. The phyla Mollusca and Annelida belong to a clade called the Lophotrochozoa, which also includes the phylum Nemertea, or ribbon worms (see: Phylum Mollusca Mollusca is the predominant phylum in marine environments, where it is estimated that 23 percent of all known marine species belong to this phylum. It is the second most diverse phylum of animals with over 75,000 described species. The name “mollusca” signifies a soft body, as the earliest descriptions of mollusks came from observations of unshelled, soft-bodied cuttlefish (squid relatives). Although mollusk body forms vary, they share key characteristics, such as a ventral, muscular foot that is typically used for locomotion; the visceral mass, which contains most of the internal organs of the animal; and a dorsal mantle, which is a flap of tissue over the visceral mass that creates a space called the mantle ...

gastropod, any member of more than 65,000 Gastropods are among the few groups of animals to have become successful in all three major habitats: the ocean, fresh waters, and land. A few gastropod types (such as General features Size range and diversity of structure Some adult Homalogyra) and forest-litter snails ( Stenopylis, Punctum) are less than one millimetre (0.04 inch) in diameter. At the other extreme, the largest land snail, the African Achatina achatina, forms a shell that is almost 20 centimetres (eight inches) long. The largest freshwater snails, Pomacea from Parenteroxenos doglieli, which lives as a Snails show a tremendous variety of shapes, based primarily upon the Planorbis; become globose with the whorls increasing rapidly in size, as in Pomacea; have the whorls become elongate and rapidly larger, as in Conus and Scaphella; have a few flatly coiled whorls that massively increase in width, as in Haliotis; become elongated and spike-shaped, as in Turritella; or be humped to form a Fissurella. Often a number of such shell shapes can be found among species within a single family, but such marine families as the Terebridae, The local abundance of snails and slugs can be spectacular. Millions of some brackish-water and freshwater species can live on small mud flats. An acre of British farmland may hold 250,000 slugs, and a Panamanian montane forest was estimated to have 7,500,000 land snails per acre. Despite this abundance, snails and slugs often pass unobserved....

MolluscaBase MolluscaBase is a taxonomically oriented database which aims to provide an authoritative, permanently updated account of all molluscan species. Mollusca are the second largest animal phylum on Earth after arthropods. The number of valid Recent species is currently estimated around 50,000 to 55,000 marine, 25,000 to 30,000 terrestrial and 6,000 to 7,000 freshwater. The number of fossil species is not known accurately, but is in the same order of magnitude and may range between 60,000 (a conservative guess, Taylor & Lewis, 2007) and more than 100,000 species. Subject to availability, the following information is provided for taxa included in MolluscaBase: • Accepted (valid) name • Classification (presented with a parent/child hierarchy) • Synonyms • Reference of original description and other relevant literature sources • Type locality and distribution • Stratigraphic range • Traits (environment, feeding type, host/parasite relationship) and notes • Images The recent, marine component coincides with the Mollusca entries in the World Register of Marine Species ( Editorial conventions The basic taxonomic unit in MolluscaBase is the binomen, i.e. the combination of a genus name and a specific epithet. Some scientists make an extensive use of subgenera and/or subspecies. Names including subgenera are flagged in MolluscaBase as "alternate representation", i.e. both name strings (with/without subgenus) are taxonomically correct, but only the binomen is flagged as "acc...

• Afrikaans • Alemannisch • አማርኛ • العربية • Aragonés • অসমীয়া • Asturianu • Avañe'ẽ • Azərbaycanca • تۆرکجه • বাংলা • Bân-lâm-gú • Башҡортса • Беларуская • Беларуская (тарашкевіца) • Български • Bosanski • Brezhoneg • Буряад • Català • Cebuano • Čeština • Cymraeg • Dansk • Deutsch • Diné bizaad • Eesti • Ελληνικά • Español • Esperanto • Estremeñu • Euskara • فارسی • Føroyskt • Français • Gaeilge • Galego • ГӀалгӀай • ગુજરાતી • 한국어 • Հայերեն • हिन्दी • Hornjoserbsce • Hrvatski • Ido • Bahasa Indonesia • Interlingua • Ирон • Íslenska • Italiano • עברית • Jawa • ಕನ್ನಡ • ქართული • Қазақша • Kernowek • Ikinyarwanda • Kiswahili • Кыргызча • Latina • Latviešu • Lëtzebuergesch • Lietuvių • Limburgs • Lingua Franca Nova • Magyar • Македонски • മലയാളം • مصرى • Bahasa Melayu • ꯃꯤꯇꯩ ꯂꯣꯟ • 閩東語 / Mìng-dĕ̤ng-ngṳ̄ • မြန်မာဘာသာ • Na Vosa Vakaviti • Nederlands • 日本語 • Napulitano • Nordfriisk • Norsk bokmål • Norsk nynorsk • Occitan • ଓଡ଼ିଆ • Oromoo • Oʻzbekcha / ўзбекча • ਪੰਜਾਬੀ • پنجابی • Plattdüütsch • Polski • Português • Română • Runa Simi • Русский • Scots • Simple English • Slovenčina • Slovenščina • Српски / srpski • Srpskohrvatski / српскохрватски • Suomi • Svenska • Tagalog • தமிழ் • Taclḥit • Tarandíne • తెలుగు • Tetun • ไทย • Тоҷикӣ • Türkçe • Українська • Vèneto • Tiếng Việt • Walon • West-Vlams • Winaray • 吴语 • ייִדיש • 粵語 • Žemaitėška • 中文 Molluscs have been and still are an important food source for A handful of mollusc species are sometimes considered hazards or pests for ...