Starfish

STARFISH

Starfish have this name because most have at least five arms extending around a disk in radial symmetry. The slow, unresponsive starfish we know comes from a very big family, ranging from beautiful designs and strong bodies to pathetic little creatures some of which are bilateral, probably in the larval stage. The most beautiful designs are rich colors with patterns of squares, and patterns of ovals.

Sea Stars
Their Phylum (classification) is echinoderms, taken from a Greek word echinos, our word “hedgehog.” We must also keep in mind that their “class,” a few levels below their “Kingdom,” is “asteroidea.” Starfish are properly called "sea stars” and thus we find the secret for the name "sea stars.” They are found at all ocean depths, and date back to the Cambrian period about 542 million years ago, the first abundant period of life when the first definitive members appeared near the beginning of that period. “Cambria” is the classical name for “Wales,” the area where rocks from the Cambrian period were first studied—but not 542 million years ago, of course. There the scientists found fossilizing multicellular organisms. This sudden appearance of hard-body fossils is referred to as the “Cambrian explosion.” The family of echinodermata contains about 7,000 living species.

Symbol of the Marine Environment
So we begin to see that these rather inactive creatures lacking in graceful movement have a very high standing--not as fish, because it is not a fish, it’s an echinoderm, closely related to sea urchins and sand dollars. But though not fish, they are synonymous with our perception of marine environment. Their respectability lies in their Kingdom's earliest entrance into the world of living creatures, their variety of design, the number of their species, and the impressive fact that they are the largest Kingdom without freshwater or terrestrial representatives. Therefore, we really stand out from them--but they swim better.

Some starfish cannot live in aquariums and some are too dangerous for aquariums.
Starfish do not rely on a jointed, movable skeleton for support and locomotion, although they do have a protective skeleton. They possess a hydraulic water vascular system with many projections called tube feet on the lower surface of the arms, and the tubes provide locomotion. There is an opening on starfish for filtering water into the vascular system. It is on the upper surface of the central disk, located away from the mouth which is in the middle of the underside. They have two stomachs, one for digestion, and the other to catch bigger prey, since their mouths would be too small. Many use a highly advanced chemical detection method to find pieces to eat here and there from old rock, which some might call the “leavings,” as they say in parts of the US. Other ones eat shellfish. The sea star devours this prey by cracking the shell with its tube feet, then pushing its own stomach through its own mouth into the open shell and using digestive juices to liquefy the interior, which can then be sucked out. Starfish are able to regenerate lost arms; even a new starfish may grow from a single arm attached to a portion of the central disk. In nature, there really is a solution for everything.

Watch Closely
We do not want to end by creating an unpleasant picture for you, so we would like you to note that your particular Starfish moves very slowly about your virtual aquarium. Also, be sure to watch the changing light. It’s enchanting.

Well, we hope you have enjoyed our little bit about the Starfish, as best we can determine as nonprofessionals.