Question

How does a hydrostatic skeleton provide support?

Answer 1

The skeleton is the supporting structure of an organism. There are generally three types of skeletons – hydrostatic skeleton, endoskeleton and exoskeleton.

Complete answer:
A hydrostatic skeleton is a flexible skeleton supported by fluid pressure. It provides shape and movement and involves two mechanical units: the muscle layers and the body wall. The fluid-filled compartment within the body is called the coelom. They are supported by the aqueous fluid, which also resists external compression. The compartment supports the other organs of the organism due to the hydrostatic pressure exerted by the liquid. This type of skeletal system is found in simple vertebrate organisms like earthworms, cnidaria, etc.
Some animals have a cavity which is filled with a blood-like substance called haemocoel. The fluid gives pressure against the muscles, which in turn contract against the pressure of the fluid. Due to the incompressibility of the fluid, it maintains a constant volume against which the muscles can contract. It prevents the collapse of the body. The muscles act against the fluid and bring about movement. If the body consists of segments, the pressure of the fluid is localised in a few of the segments.
Muscles surrounding the coelom provide movement. Contraction of the muscles in the hydrostatic skeleton brings change to the shape of the coelom whereas the pressure of the fluid in the coelom produces movement.

Note: Organisms containing a hydrostatic skeleton have advantages and disadvantages. The advantages may include: Fluid shape, Strength, Healing, Lightweight, Circulation, Protection and Suited to environment. The Disadvantages may include: Structure and surface for attachment, Lack of protection, Desiccation and Limited strength.