MOLLUSK BIBLIOGRAPHY
Mollusk is a group of invertebrates and there are over 50,000 known species of mollusk. Snails, clams, mussels are the most well known mollusk but not much people know that they are pretty similar with squid. Mollusks live almost everywhere; rocky shore, freshwater habitats and in our garden.
Generally mollusk has 3 body parts: head, visceral mass and “foot”. Head contains the sense organs and “brains”, visceral mass contains internal organs and the “foot” is the muscular part under the body that has contact with the surrounding. Mollusk is another name for shellfish. There are 3 different groups of shellfish:
There are 7 classes of mollusks:
1. Monoplacophora: rare and/or extremely deep-water creatures, also known as “bearing one plate” live at the bottom of the deep sea with soft, and muddy sea floor. They are known from the fossil record.
2. Polyplacophora: meaning “many-plated” commonly called the chitons. These creatures have 8 plates and often-found under logs and rocks in the forest. They are extremely slow moving, they might only move more than 10 feet in a year. They are able to detect the presence of light with their primitive eyes in the shells plates.
3. Aplacophora: rare and/or extremely deep-water creatures, also known as shell-less. The group contain 2 clades; Solenogastres (Neomeniomorpha) and Caudofoveata (Chaerodermomorpha) which also contain 28 families and about 320 species. Aplacophora ia considered as the ancestor of mollusk, however their relationship with other mollusk groups is unclear. Aplacophorans are cylindrical and worm-like in shape, very small (no longer than 5cm) however some species can reach 30cm in length.
4. Gastropoda: Meaning, “stomach-foot”. Snails, limpets, nudibranchs and abalones are listed in this class. All of them have shell(s) except for mudibranchs. Even though they own about 70% of mollusk species, but there are only a small number of Gastropods on land (some snails, slugs, etc)
5. Scaphapoda: rare and/or extremely deep-water creatures, the name meaning “shovel-footed” can reach 0.5-15cm in length. They live on soft substrates offshore. They feed on microscopic organism.
6. Bivalvia: meaning “two-shells” perhaps the most well known mollusk because they are used as a food source. Clams, oyster, mussels and scallops are bivalve and 80& of them live in the sea while the rest live in the fresh water. The mantle from the inside generates the shells.
7. Cephalopoda: meaning “head-footed”, these creatures are able to swim while the most of mollusk cannot. There are squid, octopus, cuttlefish and nautiluses in this class. The terms “head-footed” given from they way their body constructed. The “feet” are attached to the part of the body where the eyes are, usually called arms or mistakenly tentacles.
Cephalopods might not seem very closely related to other mollusk, but physiologically they are similar in internal construction. The most obvious difference between them and other mollusks species is they are lack of shell(s), but actually they do have shell inside their body. The only cephalopoda that has external shell is Nautiluses, which can be found in the South Pacific and Indian Oceans.
FACTS ABOUT MOLLUSKS
BY. AISYAH PUTRI
Generally mollusk has 3 body parts: head, visceral mass and “foot”. Head contains the sense organs and “brains”, visceral mass contains internal organs and the “foot” is the muscular part under the body that has contact with the surrounding. Mollusk is another name for shellfish. There are 3 different groups of shellfish:
- Hatchet-footed: these shellfish live between 2 shells that are connected by muscular which give them the ability to open and close their shell. Lines on the shells show old the mollusk is, as the shellfish gets older. Clams, scallops, oyster, and mussels are the examples.
- Belly-footed: these clams only have one-spiral shells and they also carrying their shells on their backs. They also known as univalves. Snail, slug, periwinkle and conch belong to this group.
- Head-footed: these have a head surrounded by tentacles. Squid and octopus belongs in this group.
There are 7 classes of mollusks:
1. Monoplacophora: rare and/or extremely deep-water creatures, also known as “bearing one plate” live at the bottom of the deep sea with soft, and muddy sea floor. They are known from the fossil record.
2. Polyplacophora: meaning “many-plated” commonly called the chitons. These creatures have 8 plates and often-found under logs and rocks in the forest. They are extremely slow moving, they might only move more than 10 feet in a year. They are able to detect the presence of light with their primitive eyes in the shells plates.
3. Aplacophora: rare and/or extremely deep-water creatures, also known as shell-less. The group contain 2 clades; Solenogastres (Neomeniomorpha) and Caudofoveata (Chaerodermomorpha) which also contain 28 families and about 320 species. Aplacophora ia considered as the ancestor of mollusk, however their relationship with other mollusk groups is unclear. Aplacophorans are cylindrical and worm-like in shape, very small (no longer than 5cm) however some species can reach 30cm in length.
4. Gastropoda: Meaning, “stomach-foot”. Snails, limpets, nudibranchs and abalones are listed in this class. All of them have shell(s) except for mudibranchs. Even though they own about 70% of mollusk species, but there are only a small number of Gastropods on land (some snails, slugs, etc)
5. Scaphapoda: rare and/or extremely deep-water creatures, the name meaning “shovel-footed” can reach 0.5-15cm in length. They live on soft substrates offshore. They feed on microscopic organism.
6. Bivalvia: meaning “two-shells” perhaps the most well known mollusk because they are used as a food source. Clams, oyster, mussels and scallops are bivalve and 80& of them live in the sea while the rest live in the fresh water. The mantle from the inside generates the shells.
7. Cephalopoda: meaning “head-footed”, these creatures are able to swim while the most of mollusk cannot. There are squid, octopus, cuttlefish and nautiluses in this class. The terms “head-footed” given from they way their body constructed. The “feet” are attached to the part of the body where the eyes are, usually called arms or mistakenly tentacles.
Cephalopods might not seem very closely related to other mollusk, but physiologically they are similar in internal construction. The most obvious difference between them and other mollusks species is they are lack of shell(s), but actually they do have shell inside their body. The only cephalopoda that has external shell is Nautiluses, which can be found in the South Pacific and Indian Oceans.
FACTS ABOUT MOLLUSKS
- Not only oysters that able to produce pearls! Most bivalves can produce pearls such as mussels, clams and also snails like conch. Pearls are made when a grain of sand/other small irritant stuck in the mantle of creatures. bivalve coats the irritant withe same material that secreted to produce the inner lining of the shell. this makes the irritant smooth and theoretically less painful to the bivalve.
- Mollusk use slime to variety of purposes. It helps snails and slugs move by providing lubrication and suction. Slime also provides slugs with protection by making them unpalatable or difficult for predators to pick up. Slime also prevents dehydration and helps in reproduction.
- The giant squid and the giant clam are among the worlds' largest mollusk! Member of squid in the deep sea are known to reach as much as 43 feet in length, while the giant clams can reach 440 pounds in weight and more than 47 inches.
- Some mollusk do not have shell(s)! Although many mollusks have a shell, it is not a defining characteristic of the group. Sea hares, slugs, caudofoveates, squid and octopuses are some examples of mollusks that do not have a shell.
BY. AISYAH PUTRI