Sea urchin

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Sea Urchin
A Sea urchin
A Sea urchin
Scientific classification
Kingdom: Animalia
Phylum: Echinodermata
Class: Echinoidea
Subclasses
  • Euechinoidea
    • Superorder Atelostomata
      • Order Cassiduloida
      • Order Spatangoida (heart urchins)
    • Superorder Diadematacea
      • Order Diadematoida
      • Order Echinothurioida
      • Order Pedinoida
    • Superorder Echinacea
      • Order Arbacioida
      • Order Echinoida
      • Order Phymosomatoida
      • Order Salenioida
      • Order Temnopleuroida
    • Superorder Gnathostomata
      • Order Clypeasteroida (sand dollars)
      • Order Holectypoida
  • Perischoechinoidea
    • Order Cidaroida (pencil urchins)

Sea urchins are invertebrates that live in the sea. They belong to the same family of animals as the sea stars, sea cucumbers, brittle-stars and crinoids (perhaps better known as sea lillies). Sea urchins feed on algae, mostly. Their thorns serve to protect them from predators. Stepping on them is painful, but not dangerous.

Sea otters like to eat sea urchins very much. Some humans eat the reproductive organs of sea urchins (what they call roe). This is popular in Korea. In Japan, this kind of sushi is called uni. Peopole think it is an aphorodisiac.

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