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Sea Urchin


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Sea Urchin
Sea Urchin
The sea urchin in found across the ocean floors worldwide, but rarely in the colder, polar regions. Sea urchins are commonly found along the rocky ocean floor in both shallow and deeper water and sea urchins are also commonly found inhabiting coral reefs.

There are nearly 200 different species of recognised sea urchin, that come in all shapes and sizes. Some sea urchins are covered in long thin spikes where others have a hard shell that is made up of chalky plates. The red sea urchin is the longest living creature on earth, with some living more than 200 years.

Sea urchins are omnivorous animals and therefore eat both plant and animal matter. The sea urchin mainly feeds on algae on the coral and rocks, along with decomposing matter such as dead fish, mussels, sponges ans barnacles.

Sea urchins are preyed about by many predators that inhabit their marine environment, but also those animals that don't. The main predators of the sea urchin are crabs, large fish, sea otters, eels, birds and humans. In some countries, certain species of the sea urchin are hunted and served as a delicacy.

Sea urchins have a round shaped body and with long spines that come off it. The spines of the sea urchin are used for protection, to move about, and to trap food particles that are floating around in the water. Sea urchins have five paired rows of tiny tube feet which are found amongst the spines. The feet of the sea urchin have suckers which help the sea urchin to move about, capture food, and to hold onto the ocean floor.

Sea urchins also have little claw-like structure among their spines which the sea urchin uses for protection. These structures (known as pedicellarines) are small stinging structures that are not only used for defence and obtaining food, but are also vital in keeping the body of the sea urchin clean.

The mouth of the sea urchin (known as the Aristotle's lantern), is found in the middle on the underside of the sea urchin's body and has five tooth-like plates for feeding. The anus of the sea urchin is located on the top of the body. As with other echinoderms, sea urchins do not have a brain and instead rely on their water-vascular system which is like a circulatory system and comprises of water-filled channels that run through the body of the sea urchin.

Sea urchins spawn during the spring, and the female sea urchin releases millions of tiny, jelly-coated eggs into the water that are then fertilised by the sperm of the male sea urchin. The tiny sea urchin eggs become part of the plankton and the sea urchin babies (larvae) do not hatch for several months. The sea urchin young will not become large enough to retreat from the plankton and down to the ocean floor until they are between 2 and 5 years old.

Due to dredging on the ocean floor and pollution in the water, the sea urchin populations are declining and the sea urchin and today thought to be threatened with extinction.


Sea Urchin Comments (44)

Anonymous

"how do they communicate?"

Kris leach

"this is really cool . I love it !"

bhavesh

"where are they found ?"

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Sea Urchin Facts

Kingdom:
Five groups that classify all living things...
Animalia
Phylum:
A group of animals within the animal kingdom...
Echinodermata
Class:
A group of animals within a pylum...
Echinoidea
Order:
A group of animals within a class...
Echinoida
Common Name:
Most widely used name for the species...
Sea Urchin
Scientific Name:
Comprised of the genus followed by the species...
Echinoidea
Origin:
The area where the animal first came from...
Worldwide
Size:
How long (L) or tall (H) the animal is...
3-10cm (1.2-3.9in)
Water Type:
Either freshwater, brakish or salt...
Salt
Optimum pH Level:
The perfect acidity conditions for the animal...
6.0-9.0
Life Span:
How long the animal lives for...
15-200 years
Conservation Status:
The likelihood of the animal becoming extinct...
Threatened
Skin Type:
The protective layer of the animal...
Plates
Favourite Food:Algae
Habitat:
The specific area where the animal lives...
Rocky ocean floor and coral reefs
Average Clutch Size:
The average number of eggs laif at once...
2,000,000
Main Prey:
The food that the animal gains energy from...
Algae, Fish, Barnacles
Predators:
Other animals that hunt and eat the animal...
Fish, Birds, Crabs, Sea Otter
Special Features:Small stinging structures and claw-like mouth

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