What do gastropods and cephalopods have in common

The larvae undergo torsion during development. It is a twisting that positions the visceral mass so that the anus is above the head. It is due to one side of the visceral mass growing faster than the other. The advantage or function of torsion is uncertain but it may be to balance the animal or it may be to allow the head to be withdrawn into the shell first when predators approach.

Some gastropod species are terrestrial and have lungs for gas exchange, others are aquatic and use gills. The space near the entrance to the shell that is bound by the mantle is the mantle cavity. Aquatic gastropods have gills located in the mantle cavity. The mantle of terrestrial gastropods functions as a lung.

Bivalves have two shells valves held closed by powerful muscles. The shell is produced by the underlying mantle; it grows along the outer margins. They use their foot for burrowing. Mussels use their foot for the production of threads for attachment. The gills are large because they are used for filter-feeding as well as respiration.

Food is trapped by mucus on the gills and moved by cilia. Water enters and exits through siphons. Obtain a preserved clam for dissection and place it on a dissecting tray. Remove one of the valves shells by inserting a scalpel and cutting the adductor muscles on each side of the hinge. See the diagram below for the location of the adductor muscles.

Figure 5. The anterior and posterior adductor muscles being cut so that the valves can be pulled apart. The mantle is a membrane that surrounds the internal structures and is characteristic of all mollusks.

The portion of the mantle from the exposed surface may have remained attached to the valve that was removed or it may be covering the internal structures. Find the mantle and if necessary, remove it to expose the internal structures of the clam. Identify the foot, visceral mass, gills, and labial palps. Food is trapped by mucus on the gills and moved by cilia to the mouth.

Cilia on the labial palps also direct food and mucus to the mouth. The heart can be found in the area dorsal to and slightly posterior to the visceral mass. The coelom of bivalves is reduced and limited to the area surrounding the heart.

Because the coelom is reduced, it is difficult to see the digestive organs. Cut through the visceral mass and identify the intestine. Gastropods and cephalopods have very different anatomical structures. The name cephalopod translates to "head-foot.

Gastropod means "stomach-foot. By using the site, you agree to the uses of cookies and other technology as outlined in our Policy, and to our Terms of Use. Habitat Among the most obvious differences between gastropods and cephalopods are the habitats in which they live.

Diet Cephalopods have much more specific diets than gastropods. Shell All species of gastropods, expects for slug species, have hard, external shells to protect their internal organs. Anatomy Gastropods and cephalopods have very different anatomical structures. Cephalopods are the most intelligent invertebrates. They have a highly developed nervous system with a complex brain. Moreover, they show rapid movements in the water. They can swim fast. Furthermore, they have a closed circulatory system.

Cephalopods have a series of tentacles that circle the head. They are mostly predators that feed on fish, crustaceans, worms, and other molluscs. Their well-developed camera-type eyes help them catch prey.

Some cephalopods such as octopus, squid, and cuttlefish species have the ability to change their colours. Gastropods are a group of molluscs that include snails, conchs, abalones, whelks, sea slugs, and garden slugs. It is the only group that contains terrestrial molluscs. Therefore, the majority of gastropods are terrestrial. Some gastropods live in marine water, while some other types live in freshwater.

They live in a range of habitats. Gastropods such as snails have a coiled shell. But some gastropods like slugs do not have a shell. Gastropods have a fairly well-developed head. They also have muscular foot.

Though molluscs are described as bilateral symmetrical, gastropods are asymmetrical.