Sea Urchins Anatomy

Urchins are part of the phylum echinoderm and their name comes from ancient greek echinos meaning hedgehog and derma meaning skin. Main enemies of sea urchins are otters sea birds fish crabs sunflower stars and humans.

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Sea urchin any of about 950 living species of spiny marine invertebrate animals class echinoidea phylum echinodermata with a globular body and a radial arrangement of organs shown by five bands of pores running from mouth to anus over the test internal skeleton.

Sea urchins anatomy. The internal organs are enclosed in a hard shell or test composed of fused plates of calcium carbonate covered by a thin dermis and epidermis. Males expel white sperm filled liquid into the surrounding waters while females expel yellowish eggs into the same sperm water. The test is rigid and divides into five ambulacral grooves separated by five interambulacral areas.

Sea weed algae plankton and decaying organic matter are usually on the menu of sea urchins. There are more than 900 species of sea urchins and they come in a range of colors including purple blue brown green and red. The pores accommodate tube feet which are slender extensible and often sucker tipped.

Reproductive organs in both sexes. Quizlet flashcards activities and games help you improve your grades. Sea urchins are omnivores they eat both plants and animals.

Sea urchin anatomy study guide by thomasschroeder6 includes 17 questions covering vocabulary terms and more. They belong to the phylum echinodermata which makes them closely related to sea stars crinoids and other members of the phylum. Sea urchins are tiny water creatures found in oceans in different parts of the world.

Belonging to the sub phylum echinozoa sea urchins are further divided into several sub classes. Even though sea urchins have spines they have a lot of predators. They have hard rounded shells covered with sharp movable spines.

Sea urchins have no visible eyes legs or means of propulsion but can move freely but slowly over hard surfaces using adhesive tube feet working in conjunction with the spines.

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