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Sea Cucumber

Page history last edited by rachel.mckenzie@... 11 years, 9 months ago

Sea Cucumber

Rachel McKenzie

Description

Sea cucumbers are echinoderms, a marine invertebrate with leathery skin. They have an elongated body and one sole gonad, which is an organ that produces reproductive cells. It also has a mouth surrounded by tentacles, and tube feet. Sea cucumbers have an endoskeleton just below the skin. One of the unique and interesting features of the sea cucumber is the collagen that makes up their body wall. The collagen can be loosened and tightened, therefore allowing the sea cucumber to liquefy and slip through small gaps when necessary, as well as hook up its collagen fibres to make its body firm again.

 

 

Habitat

The deep sea floor is populated by sea cucumbers; this is where they frequently make up the majority of the animal biomass. In areas deeper than 8.8 km, sea cucumbers compose 90% of the biomass. Most sea cucumbers live near rocks, corals, or seaweeds, and while most live among the sea grasses, there are some that do live in the mud or sand.

 

 

Symbiotic Interactions

A variety of fish, but most commonly pearl fish, have evolved a commensalistic symbiotic relationship with sea cucumbers. This is a symbiotic relationship in which one organism benefits and the other is unaffected.  The pearl fish live in the sea cucumber’s cloaca (otherwise known as its anus). It will benefit from this by using the cloaca as protection from predation, a source of food (by drawing in the nutrients passing in and out of the anus from the water), and as a place to help develop into the adult stage of their life. Polychaete worms and Horseshoe crabs have also taken to using the cloaca as protection.

 

 

Predator Adaptations

Sea cucumbers have tentacles (tube feet) with suction pads surrounding their mouths, and these tentacles assist greatly in helping the sea cucumber gather food items, usually tiny organisms like algae and plankton or decaying matter on the sea floor. Sea cucumbers can liquefy and slip into gaps, then extend their tentacles farther into the water to snatch up unsuspecting prey.

 

 

Prey Adaptations

Green sea turtlesHawksbill sea turtlesLoggerhead sea turtles, lobsters, Hermit crabs, Horseshoe crabs, and people eat sea cucumbers.  When threatened, sea cucumbers have their collagen at disposal, so that they can liquefy and slip into gaps and spaces to escape from their predator. Some can even shoot out their intestines, distracting the predator so that it will occupy itself with the intestines and not bother the sea cucumber. The sea cucumber will later grow new intestines. The sea cucumber can even extrude masses of white threads to entangle predators.

 

 

Species Comparison: Starfish

 

Similarities

Both organisms are from the echinoderm classifications. They both have tentacle structures called tube feet with suction pads. They are exclusively marine animals, and both of their habitats vary from deep sea trenches to coral reefs and among the sea grasses.

Differences

While starfish are carnivorous, sea cucumbers are scavenging omnivores, either sucking up decaying matter from the sea bed, mud, plankton, and algae. Starfish are characterized by radial symmetry, which means that there are several arms protruding from a central body, while sea cucumbers are bilateral.

 

 

Resources:

1.Wikipedia Foundation. Sea Cucumber. May 10th, 2012. Wikipedia Foundation. Monday, May 21st, 2012. http://en.wikipedia.org/wiki/Sea_cucumber

2.All the Sea. All the Sea Foundation. Tuesday, May 22nd, 2012. http://www.allthesea.com/Sea-Cucumbers.html

3.Sea Cucumber. January 7th, 2004. ThinkQuest. Wednesday, May 23rd, 2012. http://library.thinkquest.org/J001418/seacuc.html#

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