echinoderms 1

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ECHINODERMS

(Phylum Echinodermata)


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Characteristics

phylum ofmarine animals.

consists of sea lilies, sea stars, brittle styars,sea urchins, sand dollars and sea cucumbers.

Echinoderms are found at every ocean depth,

from the intertidal zone to the abyssal zone.

The phylum contains about 70,000 living species


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Echinoderms are also the largest phylum that hasno freshwater or terrestrial representatives.

spiny-skinned animals

Echinoderms are monoicious

Symmetry is usually radial in adults, bilateral in

larvae. Triploblastic.


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Do not have a distinct head ,excretory organs and nobrain

They poses tubular feet for motion, food handlingand respiration. A complex hemal system present.

Respiration by minute dermal branchiae (skin gills) orpapulae protruding from the coelom by tube feet


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Regeneration

A starfish cut radially into a number of parts will, over the course ofseveral months, regenerate into as many separate, viable starfish. Asection as small as a single arm (with the commensurate central-body mass and neural tissue) will, under ideal circumstances,successfully regenerate in this way.

Brittle stars, which are so named because sections of the arms caneasily break off, regenerate the missing arms.

Sea cucumbers when threatened can eviscerateeject theirinternal organs through their anusand later regenerate the lostparts.


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Three different circulatory systems:

Water vascular system - consists of the madreporite,the stone canal, the ring canal, radial canals, ampullae

and tube feet.

Transport system - body fluids circulate throughoutthe tissues

Haemal system - doesn't do much in mostechinoderms except sea cucumbers. Its main functionis to act as a "blood system"


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Reproduction

Sexual reproduction


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Importance of echinoderms

Sea urchins are a food item for humans,

Sea urchin is a popular food in Korean cuisine, and it is called "uni"

Japanese sushi cuisine.

It is also a traditional food in Chile, where it is known as an "erizo,"

highly appreciated in Spain. Apart from domestic consumption, Chile and

a number of other countries export the sea urchin to Japan in order tomeet its demand throughout the country.


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Medicinally, some varieties of sea cucumber (known asgamat inMalaysia) are said to have excellent healingproperties. There are pharmaceutical companies beingbuilt based on this gamat product. Extracts are preparedand made into oil, cream, or cosmetics. Some products

are intended to be taken internally. Claims have beenmade that sea cucumber helps a wound heal morequickly and reduces scarring.

Aesthetically, the diverse forms of the echinoderms, andtheir sometimes brilliant coloring, is often a source of joyto humans observing them.


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sea lily

Class Crinoidea


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Brittle star

Class Ophuroidea


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sea cucumbers, Cucumaria sp


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Sand dollar

Class Echinoidea

echinoderms 1

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