Question

give an account of torsion and detorsion in gastropoda

Answer 1

Torsion is a gastropod synapomorphy which occurs in all gastropods during larval development. Torsion is the rotation of the visceral mass, mantle, and shell 180˚ with respect to the head and foot of the gastropod. This brings the mantle cavity and anus to an anterior position above the head.

In some groups of gastropods (Opisthobranchia) there is a degree of secondary detorsion or rotation towards the original position; this may be only partial detorsion or full detorsion.

The torsion or twisting of the visceral mass of larval gastropods is not the same thing as the spiral coiling of the shell, which is present in many shelled gastropods.

Answer 2

Torsion And Detorsion In Gastropoda

Explanation:

1. Torsion is the revolution of the instinctive mass, mantle, and shell 180˚ concerning the head and foot of the gastropod.
2. In certain gatherings of gastropods (Opisthobranchia) there is a level of optional detorsion or pivot towards the first position this might be just fractional detorsion or full detorsion.  
3. Torsion happens during improvement in all gastropods, normally in the late veliger organize. Be that as it may, a few gastropods don't remain torted while turning out to be grown-ups.  
4. Torsion is a significant basic activity that builds part shear quality. It happens when it is curved causing bending power following up on the part, known as torque, and the subsequent pressure is known as shear stress.This stress is added to the current shear worry because of vertical and sidelong applied burdens.