Phylum mollusca questions answers. Phylum Mollusca: Class Gastropoda MCQs 2019-01-28

Phylum mollusca questions answers Rating: 7,6/10 1725 reviews

Mollusks Questions including are seashells

phylum mollusca questions answers

Classification with Characters : Class 1. In nematodes, the circulation of gases and nutrients through the pseudocoelom fluid takes place. Few Bivalves and snails inhabit freshwater or brackish water. By the modification of foot, they can creep, leap, burrow, float or swim. True gill is absent and respiration is performed by pulmonary sac or lung.

Next

Solved: QUESTION 78 Which Of The Following In NOT Unique T...

phylum mollusca questions answers

Reproductive System of Neopilina : Neopilina is a dioecious animal. Elon­gated bilaterally symmetrical worm­like bodies covered by cuticle. In annelids, the circulatory system is closed, meaning that blood circulates only inside blood vessels. In some cases the shell instead of forming an elongated spire, forms either a flattened spire Polygyrantia or a globular spire Pila. Another species was discovered during the voyage of American Research Vessel, Vema in 1958. Some squid hunt in large predatory packs which work cooperatively to bring down large prey.

Next

Phylum Mollusca: Characters and Classification (With Diagram)

phylum mollusca questions answers

Germ layers and coelom: triploblastics, coelomates. The hinge-teeth are derived from the crenulations of the shell surface. In some molluscs like Pila, due to torsion twisting during growth, the adults become asymmetrical. Mollusks can be divided into seven classes, each with distinct morphological characteristics. Four ctenidia, four auricles and four kidneys present. How can the cephalization in annelids be compared to cephalization in nematodes and platyhelminthes? Due to their diet, this class of mollusks lacks a radula. It includes 21 families with approxi­mately 200 species.

Next

Mollusks Questions including are seashells

phylum mollusca questions answers

Usually isomyarian more or less equal adductor muscles. Appendages bear suckers or hooks except Nautilus. Unionoida: i Shells oblong, ovate, elliptical or rhomboidal. In Chaetoderma and Neomenia, gametes are dis­charged into the pericardium and they ulti­mately pass out through kidney. Many members lead to amphibious life. Circulatory system: closed, with hemoglobin.

Next

Molluscs

phylum mollusca questions answers

How can they be described according to examples of representative species, basic morphology, type of symmetry, germ layers and coelom, digestive system, respiratory system, circulatory system, excretory system, nervous system and types of reproduction? Habitat: Mainly freshwater forms; a few are marine and brackish water forms. The two valves can be opened or closed by adductor muscles. Each kidney is a special portion of the coelom and remains in communication with other parts of the coelom. Molluscs play an important role in several food chains in ecosystems. Molluscs, with the exception of cephalopods, have an open circulatory system, meaning that the blood circulates within blood vessels and through the heart, as well as filling open cavities. Mollusks are predominantly a marine group of animals; however, they are known to inhabit freshwater as well as terrestrial habitats.


Next

What are some examples of phylum mollusca?

phylum mollusca questions answers

Eyespots and statocysts may be absent in some species. It acts as scavenger and keeps water clean. In terrestrial molluscs, the large network of veins under the mantle cavity absorbs air, playing the role of a primitive lung. Conchiolin constitutes a sort of mem­branous framework for the shell. The suborder is represented by three fami­lies of which: i Cirroteuthidae e. Some Molluscs are pelagic and a few are recorded to sink down to the depth of about 35,000 feet.

Next

Phylum Mollusca

phylum mollusca questions answers

Mostly non-marine gastropods, some bivalves and cephalopods are hermaphrodites. Fossil forms are not known. But the relation of the soft parts with reference to the shell differs in Spirula and Nautilus. Subclass Palaeoheterodonta Order Unionoida e. Gills when present are placed ante­rior to the heart, so the name of the subclass is Prosobranchia. Since the entire spectrum of conotoxins, as well as their mechanisms of action, are not completely known, the study of their potential applications is still in its infancy.

Next

Phylum Mollusca

phylum mollusca questions answers

Shell internal which may be reduced or absent, and when present completely surrounded by mantle tissue. It is a hermaphrodite animal. The relationships between the organisms are too convoluted C. Body Form: The body of molluscs is un-segmented with a distinct head, muscular foot and visceral hump. Relationships of Neopilina with other Molluscs : Neopilina possesses many peculiar fea­tures which make the precise relationship of it debatable. Osphradia are present in Nautilus among cephalopods.

Next

Molluscs

phylum mollusca questions answers

From which other phyla of the animal kingdom does this feature differentiate them? This species is characterized by filled um­bilicus with a concretion and colour pattern extending nearly entire shell. Acces­sory glands are usually absent in dioecious forms. Berthelinia and julia have bivalved shells. Mantle margins are not fused. Fea­tures common in Neopilina and Chiton are the shape of body, the flat ventral foot, the shell covering the head and mantle many dorso-vental muscles, auricles, numerous gills, etc. In some Gastro­pods only the left kidney originally the right kidney is persistent in the adult. There are present filamentous tentacles called the captacula, which are useful in feeding.

Next

Phylum Mollusca: Class Monoplacophora Quiz

phylum mollusca questions answers

Sex cells discharged into the pericar­dial cavity. Like all other organ systems, the excretory system in Gastropods exhibits great diversities. Gills, if present, placed behind the heart generally, hence called Opistho­branchia. Subclass Pteriomorphia Order Arcoida e. Females of some species care for the eggs for an extended period of time and may end up dying during that time period. Geological record: They range from Mississippian to the present.

Next