Sea Star

Posted by: Aamir

Jan 27th, 2007 • Category: Eye CandyTags: ,

Sea stars (also known as starfish) are spiny, hard-skinned animals that live on the rocky sea floor. Featured below is the Bat star (Asterina miniata) which comes in a wide variety of solid and mottled colors, including red, orange, yellow, brown, green and purple. They have webbing between their short, triangular arms, which gives them a bat-like look. Normally, bat stars have five arms, but they occasionally have as many as nine arms. Bat stars have sensors at the end of each arm that sense light and detect prey. When a bat star finds a food item, it extends its stomach over the prey and oozes its digestive juices onto it, liquefies the prey meal and then slurps up the resulting soup.

Sea stars exhibit a superficially radial symmetry. They typically have five “arms” which radiate from a central disk.

A new sea star may be regenerated from a single arm attached to a portion of the central disk.

These invertebrates are NOT fish; they are echinoderms. Sea stars move very slowly along the sea bed, using hundreds of tiny tube feet.

Sea stars are carnivores (meat-eaters). They eat clams, oysters, coral and other animals too slow to evade the attack (e.g. dying fish). They have two stomachs. One stomach is used for digestion, and the other stomach can be extended outward to engulf and digest prey. This feature allows the sea star to hunt prey that is much larger than its mouth would otherwise allow.

There are over 2,000 different species of sea stars worldwide and they occur in all of the Earth’s oceans. The greatest variety of sea stars is found in the tropical Indo-Pacific.


    



Posted by: Aamir

Jan 27th, 2007 • Category: Eye CandyTags: ,
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