HYDROSTATIC SKELETON Meaning and
Definition
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A hydrostatic skeleton is a structural framework found in certain soft-bodied organisms, primarily invertebrates, that provides support and enables movement without the need for bones or rigid structures. The hydrostatic skeleton consists of a fluid-filled cavity, known as a coelom, that is surrounded by flexible tissues and muscles.
The primary characteristic of a hydrostatic skeleton is the presence of an incompressible fluid within the coelom. This fluid, often called hydroskeleton, is typically water-based or gel-like and provides both support and rigidity to the organism. The fluid transmits the forces exerted by the muscles, allowing for coordinated movement and locomotion.
When muscles contract, they compress the fluid in certain regions of the coelom while expanding it in others. This creates pressure gradients, which generate force and movement. By alternately contracting and relaxing different muscle groups, the organism can change the shape and volume of its body, facilitating various types of locomotion, such as crawling, burrowing, or swimming.
Hydrostatic skeletons are found in several groups of invertebrate animals, including annelids (e.g., earthworms), cnidarians (e.g., jellyfish), and mollusks (e.g., squids). They offer flexibility and versatility in movement, making them well-adapted to a variety of environments and lifestyles. The absence of a rigid skeleton allows these organisms to maneuver through narrow spaces, squeeze into crevices, and exhibit contortions and deformations that would be impossible for animals with a more solid framework.
Etymology of HYDROSTATIC SKELETON
The word "hydrostatic skeleton" is derived from two components: "hydro-" and "static skeleton".
The prefix "hydro-" comes from the Greek word "hydor", which means water. It is commonly used in words related to water or fluid.
The term "static skeleton" refers to a structural system in an organism that provides it with support and protection. The word "skeleton" comes from the Greek word "skeletos", meaning dried up or withered. In biology, a skeleton refers to the rigid framework that supports the body, typically made of bones or cartilage.
Thus, "hydrostatic skeleton" combines these two elements, indicating a skeletal system in certain invertebrate animals, such as worms, that uses fluid-filled compartments to provide structure and support for movement.
