July 18, 2006

The Sea Cucumber


The sea cucumber is an echinoderm of the class Holothuroidea, with an elongated body and leathery skin and is mostly found on the sea floor worldwide. It is so named because of its cucumber-like shape. Like all echinoderms, sea cucumbers have an endoskeleton just below the skin.

Sea cucumbers are generally scavengers, feeding on debris in the benthic layer. Their diet consists of plankton and other organic matter found in the sea. One way they might get a supply of food is to position themselves in a current where they can catch food that flow by with their tentacles when they open. Another way is to sift through the bottom sediments using their tentacles. They can be found in great numbers beneath fish farms.

They have the peculiar adaptation of expelling first sticky threads, perhaps to incapacitate predators, and then their internal organs when startled by a potential predator. These organs can then be regrown.

When sea cucumbers are eating, by browsing the seabed, they cannot breathe through their mouth, so they can breathe through their bottom as well. Sea cucumbers reproduce by releasing sperm and ova into the ocean water. Depending on conditions, one organism can produce thousands of gametes.

(Courtesy of Wikipedia)

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