Do clams have a complete digestive system?
Clams (and all mollusks) have a complete digestive system. It consists of a mouth where food is ingested, a short connecting tube called the esophogus, a stomach which temporarily holds food, and an intestine where food digestion and absorption takes place. Food is distributed to the cells of the body by blood.
Do bivalves have a complete digestive tract?
Bivalves have a complete digestive tract; a reduced nervous system; a complete, open circulatory system with a chambered heart, arteries, veins, and blood sinuses; and excretory and reproductive organs.
Are bivalves alive?
Bivalves appear in the fossil record first in the early Cambrian more than 500 million years ago. The total number of known living species is about 9,200….Bivalvia.
| Bivalvia Temporal range: | |
|---|---|
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Subphylum: | Conchifera |
| Class: | Bivalvia Linnaeus, 1758 |
What organs do clams have?
Clams also have kidneys, a heart, a mouth, a stomach, and a nervous system. Many have a siphon.
Do clams have Buttholes?
Clams lack heads, but most can react to changes in light and some have eyes. All clams have two shells joined near a hinge structure with a flexible ligament, and all are filter feeders. Clams also have kidneys, a heart, a mouth, a stomach, a nervous system and an anus. Many have a siphon.
What are the 4 types of bivalves?
Bivalves include clams, scallops, oysters, and mussels. As their name implies, they have two parts of their shell, which can open and close.
Where does final digestion occur in the bivalves?
43 Cards in this Set
| Molluscs are | Lophotrochozoans |
|---|---|
| In the bivalves, final digestion occurs… | In the digestive gland |
| The modified veliger of some freshwater bivalves is called the… | Glochidium |
| Squids, octopuses, cuttlefishes, and nautili belong to the molluscan class… | Cephalopoda |
How many digestive openings do bivalves have and what are they called?
They are called bivalves because their shell is composed of two parts that are called valves. Is there digestive tract complete or incomplete? Explain. Incomplete, because they have one opening (mouth & anus have the same opening).
Is oyster a bivalve?
Bivalve mollusks (e.g., clams, oysters, mussels, scallops) have an external covering that is a two-part hinged shell that contains a soft-bodied invertebrate. Many bivalve species play important roles in aquatic and marine ecosystems by filtering the water and serving as habitat and prey for a variety of sea life.
What are the characteristics of bivalves?
The head is greatly reduced in size and their foot is laterally compressed. Their mantle cavity is the largest of all known molluscs. Their gills tend to be very large and not only function for respiration, but aid in food-collecting as well. Most bivalves have evolved to become burrowers.
What is the function of the stomach in bivalves?
The stomach is lined with chitin and it acts as a gizzard, crushing up the animal. The style is also much reduced in this group and may only function in coating harder particles with mucous to protect the intestine from injury. In the bivalves, one oddity does exist, the “giant clam” Tridacna gigas.
Why do bivalves live in mud?
Bivalves are highly specialized not only in their shape, but in their physiology as well. Because of this specialization, most remain living in and on “soft bottoms” such as sand, silt and well-oxygenated mud. There are a few good taxonomic data bases for one to choose from on the world wide web.
What kind of nervous system does a bivalve have?
Bivalves possess a bilateral and relatively simple nervous system. They have three pairs of ganglia and two pairs of long nerve cords. A cerebropleural ganglia is located on both sides of the esophagus and they are connected by a short commisure across the top of the esophagus .