Why do gastropods undergo torsion?

Asked by: Rosie Smith  |  Last update: 18 June 2021
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The evolution of an asymmetrical conispiral shell allowed gastropods to grow larger, but resulted in an unbalanced shell. Torsion allows repositioning of the shell, bringing the centre of gravity back to the middle of the gastropod's body, and thus helps prevent the animal or the shell from falling over.

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Additionally, Do gastropods undergo torsion?

Some gastropods undergo detorsion. In this case the embryo undergoes a full 180° torsion and then untwists approximately 90°. The mantle cavity thus opens on the tight side of the body behind the head.

Also, Why do snails go through torsion?. Garstang suggested further that torsion was an adaptation for protection. Without torsion, larval snails would retract into the shell tail first leaving the head and other important parts exposed to the teeth, claws, and tentacles of hungry predators. With torsion, larval snails would retract the head first.

Furthermore, Does snail undergo torsion?

Common garden snails have both torsion and coiling; the shells of limpets are no longer coiled, but torsion may be seen in the twisted condition of the in- ternal structures. The questions of how torsion originated and what, if anything, is its adaptive sig- nificance, are important for several rea- sons.

What is torsion and Detorsion in gastropods?

Torsion allows foot to be retracted after the head for better protection of head. DETORSION. Detorsion is reversal of torsion which takes place when during evolution shell is lost or a type of shell evolves that has openings on the opposite sides. In such situations twisting of visceral mass is not necessary.

44 related questions found

What is the effect of torsion?

Torsion is an important structural action that increases member shear strength. It occurs when it is twisted causing twisting force acting on the member, known as torque, and the resulting stress is known as shear stress. This stress is added to the existing shear stress due to vertical and lateral applied loads.

What happens during torsion?

Testicular torsion occurs when a testicle rotates, twisting the spermatic cord that brings blood to the scrotum. The reduced blood flow causes sudden and often severe pain and swelling. Testicular torsion is most common between ages 12 and 18, but it can occur at any age, even before birth.

How do snails poop?

Snails surely poop. The process is a bit bizarre by our standards, because the anus opens into the mantle cavity, which also houses the lung! So the poop itself is shed through the breathing pore. It is usually a string of green or brown matter depending on what the snail has been eating.

What does torsion mean?

1 : the twisting or wrenching of a body by the exertion of forces tending to turn one end or part about a longitudinal axis while the other is held fast or turned in the opposite direction also : the state of being twisted. 2 : the twisting of a bodily organ or part on its own axis.

How many shells does class bivalvia have?

Bivalves have two shells, connected by a flexible ligament, which encase and shield the soft vulnerable parts of the creature.

What open and closes bivalve shells?

In life the ligament opens the shell (like a bent eraser in a door hinge), and the adductor muscle or muscles close the shell (like a person pulling the door closed by the handle). When a bivalve dies, its adductor muscle(s) relax and the resilium pushes the valves open.

What is torsion animal diversity?

Gastropods are characterized by "torsion," a process that results in the rotation of the visceral mass and mantle on the foot. The result is that the mantle cavity (including anus) lies in the anterior body, over the head and mouth, and the gut and nervous system are twisted.

How do gastropods move?

Gastropods move using a single appendage—the foot. For many gastropods the power for locomotion is provided by muscular waves moving along the ventral surface of the foot13, the force of these waves being coupled to the substratum by a thin layer of pedal mucus.

Do mollusks breathe?

Aquatic mollusksbreathe” under water with gills. Gills are thin filaments that absorb gases and exchange them between the blood and surrounding water. Mollusks have a circulatory system with one or two hearts that pump blood.

Do mollusks go through larva stages?

Like many invertebrates, the mollusk life cycle includes one or more juvenile or larval stages that are very different from the adult form of the animal. Both mollusks and annelids develop through a larval stage called a trochophore larva. ... Mollusks reproduce sexually, and most species have separate sexes.

What is torsion and Detorsion in zoology?

Torsion allows foot to be retracted after the head for better protection of head. DETORSION. Detorsion is reversal of torsion which takes place when during evolution shell is lost or a type of shell evolves that has openings on the opposite sides. In such situations twisting of visceral mass is not necessary.

Can snails hear you?

Snails are almost completely blind and they don't have any mechanism of hearing sounds either. With the kind of sensory deprivation their sense of smell is extraordinary.

Do snails feel love?

What's making them so impervious, so deeply preoccupied with each other? Here's one answer: Snail sex is very complicated. Snails have a lot to think about when they make love—because they're hermaphrodites. Unlike you, garden snails can produce sperm like males and carry eggs like females at the same time.

How smart is a snail?

A snail has priority. It will always seek cover from predators and look for food as a the basis for survival. It does not contain much of a nervous system so it is most likely not "smart" but it knows how to adapt properly to survive and thrive in many environments.