Starfish: The Sea Stars of the Ocean
Saturday, 14 April 2007The body of the starfish is being supported by a complex and intricate internal skeletal composition which, because the individual skeletal elements are held together by consecutive tissue and muscle fibers, is very much flexible. The upper surface of the body is covered with small, blunt spines. The underside, or oral surface, is marked by grooves, which extend from the small central mouth outward along the center of each arm. From these ambulacral grooves protrude many tiny, minute tube feet. At the tip of each arm is a small touch-sensitive tentacle and a light sensitive eyespot. The tube feet are connected by an intricate system of canals to form a water vascular system. Seawater, flowing through this system, fills the tiny, flexible tube feet, enabling the starfish to move along the ocean bottom or to cling tightly to objects.
One magnificent characteristic that a starfish has is its ability to regenerate. For example, if one arm of the starfish was accidentally broken or cut-off, it will regenerate it. More amazing is the fact that at times the entire body is able to be regenerated from just a fragment of the central disc, the central part of the body.
Starfishes feed on mollusks, crustaceans, and other marine invertebrates or any water organism that are slow moving. Starfishes cause a great loss in oyster beds where by gripping the opposite valves of the oyster’s shell with their tube feet, they exert a steady pull until the shell is forced open. The stomach is then averted over the oyster’s soft body and the oyster is digested in place. Starfish’s digestion of food is being carried by two separate stomachs – the cardiac and the pyloric stomach each bearing a complex job of digesting the food intake of the starfish.
Among the more common starfishes is asterias forbesi, which occurs along the Atlantic coast of North America. It has five arms, is brownish in hue, and attains a spread of from 6 inches to a foot. The sunflower star occurs along the Pacific coast. It has 18 up to 24 arms and spreads to up to 30 inches.
Truly amazing, the starfishes even when they are regarded as not fishes due to their anatomical composition, the fact that they are able to survive in the water system gives them the right to be called as a contributing life form in the ecology of water. Rightfully, the starfishes are to be called as SEA STARS not only because they are not real fishes but because just like the stars in the galaxy, the starfishes bring bright in the entire bodies of water.
