Are mollusks Coelomates?
Although molluscs are coelomates, their coeloms are reduced to fairly small spaces enclosing the heart and gonads. The main body cavity is a hemocoel through which blood and coelomic fluid circulate and which encloses most of the other internal organs.
Does Mollusca have true segmentation?
Mollusks are mostly dioecious and are divided into seven classes. The phylum Annelida includes worm-like, segmented animals. Segmentation is both external and internal, which is called metamerism.
Why do molluscs and arthropods have reduced coelom?
The body cavity or the coelom of arthropods and molluscs is filled with blood. The haemocoel is an enlarged blastocoel, which greatly reduces the coelom (this is restricted to the cavities of the gonads and excretory organs). The haemocoel can act as a hydrostatic skeleton.
Do molluscs have true Nephridial system?
Molluscs also have a well-developed excretory system, using tubular nephridia organized as kidneys, that collect liquid wastes from the coelom and dump them in the mantle cavity, where they are pumped out of the shell.
Is Mollusca a Pseudocoelomate?
Type of Coelom: Animals in Mollusca are coelomates. Examples of phylum Mollusca are Sea Hares, Sea Butterfly, Squid, Octopus, and cuttlefish. So, the correct answer is ‘Nematoda’.
Which of the following accurately describes the coelom in mollusks?
Which of the following accurately describes the coelom in mollusks? It is highly reduced. It is in spaces around the excretory organs, the heart, and part of the intestine.
What are characteristics of Mollusca?
Mollusca Characteristics
- They are mostly found in marine and freshwater.
- 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.
Do arthropods have a true coelom?
Similar to annelids, arthropods are coelomates with a true coelom, or body cavity. However, in arthropods the coelom is reduced to a small compartment surrounding the reproductive and excretory organs.
How do molluscs differ from other animals?
Molluscs have a mantle or mass of soft flesh that covers the soft body and encloses the internal organs. In many species, the mantle produces a hard shell. Not all molluscs produce a shell. Many molluscs have a radula, which, in most species, is a rasp-like scraping organ used in feeding (Fig.
Are mollusks Acoelomates pseudocoelomates or coelomates?
protostome coelomates
The protostome coelomates (acoelomates and pseudocoelomates are also protostomes) include the mollusks, annelids, arthropods, pogonophorans, apometamerans, tardigrades, onychophorans, phoronids, brachiopods, and bryozoans.
Are mollusks pseudocoelomates?
In pseudocoelomates, mesoderm and endoderm are separated by the body cavity, limiting developmental interactions between these tissues. The only major phylum of coelomates without segmented bodies are the Mollusca.
Which phylum does not have a true coelom?
So, the correct answer is ‘Platyhelminthes’.