Monday, February 1, 2010


Echinoderm means "spiny skin."Echinodermata always starts from a larvae stage and has approximately 7000 described living species and about 13,000 extinct species known from the fossil record. This phylum is the largest without any freshwater or terrestrial forms. Mainly a marine group, echinoderms are found in all the oceans.
An internal skeleton is present throughout members of the phylum. The skeletal and muscular arrangement varies among groups but mostly RADIALLY SYMMETRICAL. It also has a poorly defined open circulatory system. The OSSICLES are calcareous plates buried in the fleshy region beneath the outer skin. This represents the endoskeletonwhich gives the body rigidity and support. Echinoderms in general are most vulnerable in their larval stage. As adults, asteroids have an anti-predator adaptation where they can lose an arm to a predator and the arm is later regenerated. Sea urchin eggs are also edible and often served in sushi bars. Echinodermata includes the starfish, sea urchins, brittle stars, sea cucumbers and feather stars.


  1. Mr. Jaren, this is Emmanuela Michelle and Natasha Ureyang from 7 PIB 3
    We would like to ask you some questions about echinodermata. Please anwer it
    -What is open circulatory system? (sorry, we forgot about it)
    -What is asteroid?
    -What is the difference between feather star and starfist?
    thank you Mr.

  2. Emamanuela and Natasha,

    Thank you for asking these questions.

    1. An open circulatory system means that the body of an animal does not have any blood vessels such as arteries, veins and etc.

    2. An asteroid is a species of starfish.
    3. They're basically different kind of starfishes.

    Mr. Jaren

  3. Thank you for answering our questions
    Emmanuela and Natasha

  4. Mr.Jaren is coelentereta and cnidaria the same?
    please answer it before the chapter test!


  5. Mr jaren is nemathelminthes same with nemertinea

    thank you

  6. To Elsa,
    Thank you for asking. Coelenterata and cndaria are one and the same. Cndarian is just another name for the phylum that the jelly fish and some corals belong to.

    Mr. Jaren

  7. To Elza,

    The same goes for nemathelmintes and nemertinea, they are the same.

    Mr. Jaren

  8. Mr Jaren, I want to ask about cestoda...
    1. Can Cestoda get out from the human intestines then spread to other organs?
    2. Can they eat most of the part of the intestine walls?
    And then I want to ask about Echinodermata...
    1. How Echinodermata move in the marine/ocean?
    2. Are the larvae of the Echinodermata finds food by themselves or been feed by their parents?
    3. Who are the predators of Echinodermata?
    4. How the adults can against the predators?
    Ad the last, mamalia.... (Placentals)
    1. Did the Placentals ever happens this incident? "One day the placenta ever torn and one of the body parts can get out from their placentas"
    Thank you...

    From Celine Angelina 7pib2

  9. to Mr Jaren, thanks for replying my question


  10. To Celine,
    1. Class Cestoda can definitely invade other internal organs of the body.
    2. Tapeworms doesn't literally eat but they actually ABSORB nutrients from a host's body.
    3. Their movement is brought about the bristles under the body, it looks like hundreds of tiny legs.
    4. Other large fishes.
    5. Sometimes they lose a body part to distract its predator.
    6. As far as I know, it doesn't happen.

    Mr. Jaren

  11. Thank You Mr.Jaren....