Filum Mollusca
Mollusca name is derived from the Latin 'molluscus' which means soft. Molluscs is the second largest phylum in the animal kingdom, after the phylum Arthropoda. Currently there are an estimated 75 thousand kinds, as well as 35 thousand kinds in the form of fossils. Molluscs living in marine, freshwater, brackish, and land, from the trough, continents, sea, until the high mountains, even easily be found around our homes.
Characteristic Features:
1. The size and shape varies molluscs.2. Bodied soft and not jointed.
3. Animal triplobastik selomata.
4. Not having a spine
5. Life in the water and on land
6. Have the nerve ring that is the nervous system
7. The organs of excretion form nephridial
8. Have a radula (tongue toothed).
9. Animal Heterotof
10. reproduce sexually
11. The structure of bilateral symmetry body
12. The body consists of a foot, visceral mass and mineral
Digestive System
Mollusca complete digestive system, consisting of the mouth, esophagus, stomach, intestine and anus. Except in Pelecypoda, in the oral cavity molluscs are radula (tongue grated). Radula consists of cartilage (odontophore) on which there are several rows of teeth chitin whose tip leads into. Radula serves to scrape moss, grazing, drilling, and capture prey. The anus is located on the edge of the dorsal mantle cavity, in the posterior part. Waste products in the form of solid pellets, so it does not pollute the mantle cavity. In addition, there is also a digestive glands are well developed.
Respiratory system
Molluscs that live in water breathe with gills or more so-called ktenidium, paruatau both lungs. While living on land do not have gills. Air exchange molluscs carried in the blood vascular mantle cavity that serves as the lungs. Tools excretion in the form of a pair of protonefridium.
Sistem Sirkulasi
Sistem
peredaran darah Mollusca merupakan sistem peredaran darah terbuka, karena darah
tidak beredar di dalam pembuluh darah tetapi di dalam sinus darah (rongga di
antara sel-sel organ). Jantung pada hewan ini sudah terdapat atrium (serambi)
dan ventrikel (bilik) serta terdapat pembuluh darah vena dan arteri, misalnya
pada kelas Gastropoda. Jantung Mollusca terdiri atas dua serambi (aurikel) dan
satu bilik (ventrikel).
Pigmen darah
hemosianin yang larut dalam plasma darah mengandung Cu, bukan Fe; berwarna biru
pucat bila mengandung oksigen daan tidak berwarna bila kekurangan oksigen.
Nervous System
Nervous system nerve encircling ring-shaped with three pairs of esophageal ganglion ganglion namely cerebral, visceral ganglion and ganglion nerve fibers pedal with wide and two pairs of nerve fibers associated with foot, mantle, and internal organs.
Reproductive System
Molluscs including hermaphroditic animals, which have both male and female genitalia in a single individual (monoecious), but there is also a separate genitals (married two). Molluscs reproduce sexually and each of the sexual organs apart from each other in individual lain.Fertilisasi done internally and externally to generate telur.Telur develop into larvae and develop further into mature individuals.
locomotion
Locomotion between molluscans varies, and is determined by the structure of the foot. Herbivorous forms generally glider, moves in waves of muscle contraction. However, many forms of carnivores has reached a more advanced form of propulsion. Squid swim actively by the type of jet propulsion, where the water is quickly removed from the mantle cavity through the siphon. In the squid efficient this technique has allowed for the animal to reach the fastest speed of any aquatic invertebrates. The Squid and the Sea Hares rely lateral corrugated fins to move very maneuverable. In bivalves foot has evolved into a tool for digging, which can be very fast, for example in the Razor Shells.
Mollusca role in Life
1. The role of the favorable
a, As a counterweight in the ecosystem
b. As a source of protein-containing foods
c. As a pearl
d. as a garnish
a. Achatina fulica and Pomacea caniculata become pests for agriculture
b. Some types of shells into intermediate host for the parasitic worms in humans
b. As a source of protein-containing foods
c. As a pearl
d. as a garnish
2. Role of adverse
a. Achatina fulica and Pomacea caniculata become pests for agriculture
b. Some types of shells into intermediate host for the parasitic worms in humans
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