ACTIVITY #6

MOLLUSCA

Name: ________________________________________________________ Score: _____________Course/Yr & Sec.: __________ Group #: __________ Date: __________ Prof.: _________________

I. Table 1. Fresh Specimen Examined

Name of the Specimen / Class Distinctive Feature / Characteristics

Green Mussel Class: Bivalvia

Squid Class: Cephalopoda

Snail Class: Gastropoda

Brown Clam/Mussel Class: Bivalvia

Octopus Class: Cephalopoda

It is a large mussel 80-165mm in length. Young ones have a distinctive bright green shell, which fades to brown with green edges in adults. The exterior surface of the shell is smooth with concentric growth rings and a slightly concave ventral margin. The inner surface of the shell is smooth with a pale blue to green hue. The ridge, which supports the ligament connecting the two shell valves, is finely pitted.

Asian clams (brown clams/mussels) are oval to nearly triangular in shape, reaching 50 mm in length. The exterior of the shell is normally a yellow-green to brown in color with thick, concentric rings. Internally they may be white or purple and have long, leaf-like lateral teeth on each side of the beak (native freshwater mussels have only lateral teeth on one side of the beak or lack them entirely).

The main body mass is enclosed in the mantle, which has a swimming fin along each side. These fins are not the main source of locomotion. The skin is covered in chromatophores, which enable the squid to change color to suit its surroundings, making it practically invisible. The underside is also almost always lighter than the topside, to provide camouflage from both prey and predator.

The octopus has an ink sack, opening near the anus, from which it can discharge a dense, sepia-colored fluid, creating a smoke screen, and it can also change its color patterns to become concealed in its surroundings. The common octopus would be unique for its appearance alone, with its massive bulbous head, large eyes, and eight distinctive arms.

Snails are gastropods, and have coiled shells and retractable tentacles on their heads that are sometimes tipped with eyes. Their rasp-liked tongue, the radula, saws away at food. Their most distinctive feature, though, is torsion. They are twisted in such a way that the back half of their body sits above their heads, facing forward. Only one group of gastropods does not show torsion.

II. Draw the Fresh Specimen and label their parts and give their Taxonomic Account.

Taxonomic Account

Phylum: MolluscaClass: BivalviaOrder: MytiloidaFamily: MytilidaeGenus: PernaSpecies: P. viridis

Scientific Name:Perna viridis

Common Name:Asian green mussel

Taxonomic Account

Phylum: MolluscaClass: CephalopodaOrder: TeuthidaFamily: LoliginidaeGenus: LolligunculaSpecies: L. brevis

Scientific Name:Lolliguncula brevis

Common Name:Atlantic brief squid

Taxonomic Account

Phylum: MolluscaClass: GastropodaOrder: NeotaenioglossaFamily: BithyniidaeGenus: BithyniaSpecies: B. tentaculata

Scientific Name:Bithynia tentaculata

Common Name:Faucet snail

Taxonomic Account

Phylum: MolluscaClass: BivalviaOrder: VeneroidaFamily: CorbiculidaeGenus: CorbiculaSpecies: C. fluminea

Scientific Name:Corbicula fluminea

Common Name:Asian clam

Taxonomic Account

Phylum: MolluscaClass: CephalopodaOrder: OctopodaFamily: OctopodidaeGenus: OctopusSpecies: O. vulgaris

Scientific Name:Octopus vulgaris

Common Name:Common octopus

III. Preserved Specimen

It is a species of bivalve mollusk in the family Carditidae. It can be found along the Atlantic coast of North America, ranging from North Carolina to Florida.

Tapestry turban is a species of sea snail, marine gastropod mollusk in the family Turbinidae. The length of the shell varies between 30 mm and 100 mm.

Clibanarius vittatus lives inside the empty shell of a gastropod mollusc. It is found the Caribbean Sea, the Gulf of Mexico and the western Atlantic Ocean.

Phalium bandatum, or the bonnet shell, is a species of sea snail, from the family Cassidae. The size of an adult shell varies between 40 mm and 140 mm.

A large, well-known family of usually white, hard-shelled clams in which the cardinal teeth are small and the anterior muscle scar is narrow and long.

It is called "money cowry" because the shells were used in many Pacific and Indian Ocean countries as a form of exchange before coinage was in common usage.

Like other clams, it is a filter feeder. This species has a large, heavy shell that ranges from being a pale brownish color to shades of gray and white. 

The adult bears a hard, thin calcareous shell 25-40 mm in diameter and 25-35 mm high, with four or five whorls. The shell is somewhat variable in color.

This species lives in shallow water, crawling and burrowing into the sand. The shell is thin, globose and fragile. The last whorl covers the rest of the whorls.

Bubble conches lay eggs in long strands: the eggs are contained in twisted gelatinous tubes. Strombus bulla moves with a leaping motion.

White Shelled Hermit crab (Dardanus lagopodes), which usually inhabits shells with wide openings, lived underwater in the Red Sea.

Anadara lienosa is a species of saltwater bivalves, commonly called as ark clams, in the family Arcidae.

Dardanus pedunculatus usually attain a maximum size of 10 cm (4 in). The carapace is mottled in tan and cream, while the eyestalks are white with red bands.

 This species is a robust brown snail, 2 cm high, with dark brown markings and a pointed spire. The shell is thin, with 6 to 7 whorls and a sharp apex.

The adult bears a hard, thin calcareous shell 25-40 mm in diameter and 25-35 mm high, with four or five whorls. The shell is somewhat variable in color.

Shells of the Pecten sp consist of two valves which are circular to broadly ovate with the right valve usually more inflated than the left valve.

Conch shell is a tropical marine gastropod mollusk, in the genus Strombus, having large, often brightly colored spiral shells and edible flesh.

The shell background color is a creamy white. Different individuals may have shells with varying degrees of pale to dark brown markings.

Conus geographus has a broad, thin shell, cylindrically inflated. It grows to about 4-6 inches in length. The size of an adult shell varies between 43 mm and 166 mm.

Thorny oyster is more closely related to the scallop. They have a well developed middle mantle that carries sensory tentacles with multiple eyes around the shell edges.

The size of the shell is generally between 35 mm and 60 mm (maximum 90 mm). It is a purple-gray mottled with brown-black dotted spots.

Ostrea edulis is a species of oyster native to Europe and commonly known as the European flat oyster. Adults range from 3.8-11 cm (1.5 to 4.3 in) across.

Cypraeidae have adult shells which are very rounded, almost like an egg; they do not look like a typical gastropod shell because the shells are extremely smooth and shiny.

Teeth coarse, extending only slightly out of the aperture. Base rounded, white or partly fawn. The whole surface marked with white spots of varying size.

These attractive univalve mollusks are highly valued by shell collectors. They usually grow to around 10 cm in length and have very distinguished colors and patterns.

The shell of Acanthocardia tuberculata can reach a size of about 95 mm. This shell is robust, equivalve, inflated and slightly inequilateral, with crenulated margins.

The shell of Venerupis philippinarum is elongate, oval, and sculptured with radiating ribs. It grows to 7.5 cm (3.0 in) across and 3.5 cm (1.4 in) in width.

Cardita laticostate is a bivalve mollusc of the family Carditidae. It is found from low tide to depths of approximately 185 m.

Cerastoderma edule, commonly known as the common cockle, is a species of edible saltwater clam. This species is found in coastal areas of the eastern Atlantic Ocean.

Lucina sp in the family Lucinidae is a family of saltwater clams, marine bivalve mollusks. They have rounded shells with forward-facing projections.

Species that make up the family Cancellariidae are quite diverse. Most are under an inch (25mm) in size, though some Panamic species are known to reach 4 or 5 in. 

It is called "money cowry" because the shells were used in many Pacific and Indian Ocean countries as a form of exchange before coinage was in common usage.

Adult snails have a height of around 7 cm and their length can reach 20 cm or more. The shell has a conical shape, being about twice as high as it is broad.

They reach on average 38-50 mm of length, and a maximum size of 90 mm. The shells of these cowries may various in pattern and size.

Little bear conch has a varied coloration of white, cream or brown with contrasting spotted color. It is basically 3-5cm length with thicker shell.

Murex belongs to the family Muricidae. Their elongate shells highly sculptured with spines or fronds. The inner surfaces of their ornate shells are often brightly colored.

The distinctive rounded shells of common cockles are symmetrical and are heart-shaped when viewed from the end.

The shell of Lioconcha castrensis reaches a maximum length of about 55 mm. The shape of the shell is trigonal ovate and this species is equivalve.

Dardanus guttatus, also known as Blue-knee hermit, is carnivorous. It is an active hunter for snails, clams and other small invertebrates as well as small fish.

Batillaria zonalis is a species of small sandy shore snail, a marine gastropod mollusk in the family Batillariidae, the horn snails.

Thin, acute, coeloconoid (approaching conical shape but with concave sides) shell is imperforate or rarely umbilicate, with numerous spiral lines.

Pagurus bernhardus is the common marine hermit crab of Europe's Atlantic coasts. It is about 3.5 cm long, and is found in both rocky and sandy areas.

IV. QUESTIONS

1. What characteristics distinguish phylum Mollusca?

These are the following characteristics that may distinguish the phylum Mollusca: (1) they are

bilaterally symmetrical; (2) their bodies have more than two cell layers, tissues and organs; (3) absent

of different cavities; (4) body possesses a through gut with mouth and anus; (5) has body monomeric

and highly variable in form, may possess a dorsal or lateral shells of protein and calcareous spicules;

(6) has a nervous system with a circum-esophageal ring, ganglia and paired nerve chords; (7) has an

open circulatory system with a heart and an aorta; (8) has gaseous exchange organs called ctenidial

gills; (9) has a pair of kidneys; (10) reproduction normally sexual and gonochoristic; (11) they feed a

wide range of material and lastly; (12) different species from phylum Mollusca live in many types of

environments (terrestrial or marine habitats).

2. Give the ecological importance of mollusks.

Mollusks play an important role in several food chains in ecosystems. Mollusks, which include

land snails, freshwater snails, mussels, clams, and slugs, are vital to healthy ecosystems. They provide

not only food for small animals like birds and fish, but they also supply recycling forest nutrients from

plants and animal wastes, essentially keeping water clean and healthy. Other marine mollusks like

octopus and squid are part of a common human diet, very appreciated in the East, and even oysters

and mussels, consumed all around the world. They are considered as excellent ecological indicators for

they provide a window into the health of the entire ecosystems. Besides, mollusks that are part of the

food industry, pearls for example, made by oysters have high commercial value.

References:

http://en.wikipedia.org/wiki/Perna_viridishttp://en.wikipedia.org/wiki/Lolliguncula_brevishttp://en.wikipedia.org/wiki/Bithynia_tentaculatahttp://en.wikipedia.org/wiki/Corbicula_flumineahttp://en.wikipedia.org/wiki/Common_octopushttp://www.earthlife.net/inverts/mollusca.htmlhttp://www.habitat.noaa.gov/pdf/best_management_practices/Preventing%20Spread%20of%20Invasive%20Bivalve%20Species.pdfhttp://animals.nationalgeographic.com/animals/invertebrates/common-octopus/http://www.life123.com/home-garden/gardening-tips/garden-pests/snail-facts.shtmlhttp://www.biology-questions-and-answers.com/mollusca.html