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Why do bivalves lack a radula?

Most bivalves do not have radula because they eat by filtering water through their gills to obtain organic particles. Most bivalves attach themselves to something or burrow underground.

How do bivalves feed?

Like fish, bivalve mollusks breathe through their gills. As filter feeders, bivalves gather food through their gills. Some bivalves have a pointed, retractable “foot” that protrudes from the shell and digs into the surrounding sediment, effectively enabling the creature to move or burrow.

Does a mussel have a radula?

Clams, oysters, scallops, and mussels are bivalves. This type of mollusk does not have a radula. They are mostly filter-feeders.

Do all mollusks have a shell?

Among the Mollusks are some of the most well known of invertebrate sea creatures, like snails, clams, mussels, squid, and octopods. Mollusks usually have a shell (although some do not). Mollusks also have an extension of the body wall called the mantle.

Why is a closed circulatory system better?

Still, blood can flow backward and the system is only slightly more efficient than the open system of insects. The closed circulatory system has more advantages over the open circulatory system. 1. The blood transfers faster in the closed system, thus oxygen, nutritients, and wastes transport fast also.

What is the name of the fluid that is pumped through an open circulatory system?

hemolymph

Do annelids have open circulatory system?

Much like humans, annelids have a closed circulatory system, which means the blood circulates through a closed network of blood vessels. The heart-like structures in the earthworm are called aortic arches, which pump blood out into the network of vessels that run in a circuit through the body.

Does a snail have a closed circulatory system?

Cephalopods have a closed circulatory system. A Snail has an open circulatory system which means that blood is not restricted from travelling within the blood vessels. The heart of the snail is found on the left side of the body and is made up of one auricle and one ventricle.

Why do grasshoppers have an open circulatory system?

There are two types of circulatory system; closed and open circulatory system. Grasshoppers have an open circulatory system, which is different from that of vertebrates and other invertebrates. An open circulatory system is beneficial because animals don’t have a blood pressure, so they can live at great ocean depths.

Do grasshoppers have hearts?

Like other insects, grasshoppers have an open circulatory system and their body cavities are filled with haemolymph. A heart-like structure in the upper part of the abdomen pumps the fluid to the head from where it percolates past the tissues and organs on its way back to the abdomen.