The hinge teeth (consisting of cardinal and lateral teeth) interlock on the two valves preventing slippage. Differences in the nature of the hinge teeth are important in the classification of bivalves.
Where are the hinge teeth on a clam?
The hinge has 2 lateral serrated teeth in each side of the right valve and one on each side of the left valve. and 2 lateral teeth are what most distinguish the Asian Clam from our native clams.
What is the hinge ligament?
A hinge ligament is a crucial part of the anatomical structure of a bivalve shell, i.e. the shell of a bivalve mollusk. … The ligament is made of a strong, flexible and elastic, fibrous, proteinaceous material which is usually pale brown, dark brown or black in color.
Where is the hinge line located?
A hinge line is an imaginary longitudinal line along the dorsal edge of the shell of a bivalve mollusk where the two valves hinge or articulate.
Do bivalves show Cephalization?
Bivalves are a bit of an exception to the cephalization that characterizes most mollusks. Bivalves don’t have a head. They feed by filtering out food from the water in which they live. They actually eat with the same structure used for breathing: the gills.
What is the mantle cavity?
Definition of mantle cavity
: the cavity between the mantle and the body proper of a mollusk or brachiopod in which the respiratory organs lie.
What are cardinal teeth?
Definition of cardinal tooth
: a tooth of the hinge of a bivalve mollusk’s shell situated just under the umbo and often relatively large — compare lateral tooth.
What are differentiated teeth?
In vertebrates, heterodont pertains to animals where teeth are differentiated into different forms. For example, members of the Synapsida generally possess incisors, canines (“eyeteeth”), premolars, and molars. … In contrast, homodont or isodont dentition refers to a set of teeth that possess the same tooth morphology.
Does an oyster have teeth?
Oysters have very small hinge teeth. Most bivalves have more prominent teeth that can be used to help identify the species. The hinge has two ligaments. The external ligament is flexible and provides the axis of move ment for the two halves of the shell.
What does the hinge ligament allow?
Hinge joints allow the movement of certain parts of the body in one plane. There are hinge joints in the fingers, toes, knees, elbows, and ankles. Although hinge joints are stable, people can still dislocate a bone in them. Osteoarthritis is common in hinge joints.
What muscles open and close clams?
Have you ever tried to open a clam by hand? It’s very difficult because the clam has two powerful lateral muscles called “adductor muscles” that allow the clam to close shut.
What is the hinge ligament structure known as in mussels?
Hinge teeth are part of the anatomical structure of the inner surface of a bivalve shell, i.e. the shell of a bivalve mollusk. … To make this possible, in most cases the two valves are articulated using an arrangement of structures known as hinge teeth (often referred to collectively as the “dentition“).
What is the meaning of hinge line?
Definition of hinge line
1a : an imaginary line on the earth’s surface which can be regarded as a boundary between a stable region and one undergoing upward or downward movement. b : a line around which one wall of a fault may appear to have rotated with respect to the other wall.
What is the hinge line of a fold?
Hinge line = where the limbs of the fold meet. It is also the line of maximum curvature. Axial Surface (or Axial Plane if it’s not curved) of a stack of folds passes through the hinge lines and most nearly divides the fold into two equal parts.
What is a cylindrical fold?
Cylindricity. Cylindrical folds. Folds are often drawn as cylindrical structures, meaning that the fold axis is a straight line which, when moved parallel to itself, generates any single fold of the same generation. The axis of cylindricity is parallel to the fold axis.
Do Chitons have cephalization?
The ancestral mollusc probably resembled a chiton, a flattened worm like animal protected by a dorsal shell. … Both flatworms and molluscs are triploblastic, bilaterally symmetric, and cephalized.
Are scallops cephalized?
A handful of ocean animals possess basic nervous systems devised as a nerve net, with no head. These organisms include Cnidarians, such as coral, jellyfish, sea anemones and simple mollusks like scallops. Echinoderms, or sea stars, also lack cephalization.
Do cephalopods exhibit cephalization?
In particular, the appropriately named cephalopods (the group that includes the squid and octopus) are characterized by an advanced degree of cephalization. Their sense organs, including well-developed eyes and a brain, are concentrated in a distinct head region.
What organisms have mantles?
mantle, also called pallium, plural pallia, or palliums, in biology, soft covering, formed from the body wall, of brachiopods and mollusks; also, the fleshy outer covering, sometimes strengthened by calcified plates, of barnacles. The mantle of mollusks and brachiopods secretes the shell in species that possess shells.
What is Monopectinate?
: pectinate along one side.
Who will take up the mantle?
Elijah, a prophet of God, leaves his mantle, or cloak, once he ascends to heaven. Elisha, “picks up the mantle,” taking his Elijah’s place as a prophet.
What is a bivalve muscle?
The adductor muscles are the main muscular system in bivalve mollusks (e.g. in clams, scallops, mussels, oysters, etc.). In many parts of the world, when people eat scallops, the adductor muscles are the only part of the soft parts of the animal which are eaten.
What is the difference between brachiopods and bivalves?
The key to distinguishing brachiopods from bivalves is determining their lines of symmetry. Bivalves have a plane of symmetry that cuts between their two valves. … Bivalves are often described as having left and right valves. Brachiopods have a plane of symmetry that cuts across the two valves.
Do bivalves shell?
Bivalves by definition possess two shells or valves, a “right valve” and a “left valve”, that are joined by a ligament. The two valves usually articulate with one another using structures known as “teeth” which are situated along the hinge line. … The shells of bivalves are equal sides connected by a hinge.
What is pleurodont teeth?
Pleurodont is a form of tooth implantation common in reptiles of the order Squamata, as well as in at least one temnospondyl. The labial (cheek) side of pleurodont teeth are fused (ankylosed) to the inner surface of the jaw bones which host them.
What is mammalian tooth?
Mammal teeth are specialized for their diets. Mammal teeth can look really different from each other. But mammals’ mouths have four main types of teeth: incisors, canines, premolars, and molars. Incisors. Incisors are the teeth at the front of your mouth.
What is mammalian dentition?
Meaning of Dentition in Mammals: The arrangement of teeth in the upper and lower jaws, mainly on the premaxilla, maxilla and dentary bones, is called dentition. Absence of teeth: Modern turtles and birds lack teeth. Teeth are present in all mammals though a secondary toothless condition is found in some mammals.
Do oysters have tentacles?
Some oysters make beautiful pearls that are used in jewelry. The last group of mollusks is the cephalopods (SEF ul o pods). … These mollusks capture food with their flexible, muscular tentacles. Sensitive suckers on the tentacles have the senses of taste and touch.
Do shellfish have teeth?
Lobsters and crabs have teeth— in their stomachs. These are used to crush its food, but they also have a strange secondary function in ghost crabs: making a noise that wards off predators.
Do mussels have teeth?
The Shells
Some mussels have interlocking hinge “teeth” (pseudocardinal teeth and lateral teeth) on the inside of the shell to help keep the two valves in proper alignment. Other species are toothless.
What are examples of hinge joints?
[3][4] The hinge joints of the body include the elbow, knee, interphalangeal (IP) joints of the hand and foot and the tibiotalar joint of the ankle.
Is jaw a hinge joint?
Opening and closing the jaw is a simple hinge action while side-to-side jaw movement requires a sliding action of the joint. Chewing food requires a combination of these movements.
Is hinge joint?
Hinge joint | |
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TA2 | 1558 |
FMA | 75296 |
Anatomical terminology |
How does clam breathe?
Clams are under the water during high tide and are uncovered on the tide flats during low tide. To protect themselves clams burrow down in the mud and sand using their foot. … When the tide comes in, they stick their siphons out and inhale fresh seawater to get oxygen so they can breathe.
How water passes through a clam?
The clam has a pair of very large gills, and the surface of the gills is covered with cilia. The cilia beat in a coordinated fashion, and the movement of the cilia cause water to move into and through the clam. Food-containing water enters through the incurrent siphon and passes over the gills.
Why do clams open their shells?
Clams close their shells with powerful adductor muscles which pull the two valves together. A springy ligament at the hinge pulls the shell open when the muscles relax. Just like us, the clam needs to use nerve cells to signal the muscle to do its thing.
What is the function of the tooth like projections on a clam?
What is the function of the tooth-like projections at the dorsal edge of the clam’s valves? These microscopic teeth help make sure that the valves align properly while closing. To make sure that the shells form a tight seal of protection.
What is bivalve shell made of?
The bivalve shell is made of calcium carbonate embedded in an organic matrix secreted by the mantle. The periostracum, the outermost organic layer, is secreted by the inner surface of the outer mantle fold at the mantle margin.
Where are a clams eyes?
Giant clams possess several hundred small pinhole eyes (or also known as ‘hyaline organs’) on the exposed mantle (Kawaguti & Mabuchi 1969; Land 2003). These ‘eyes’ are light-sensitive, which allows them to detect changes in light levels, i.e. dark versus light.
What is a limb in geology?
The limbs are the sides of the fold that display less curvature. The inflection point is the area on the limbs where the curvature changes direction. The axial surface is an imaginary plane connecting the hinge of each layer of rock stratum through the cross sectional anticline.