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Jellyfish (Class Scyphozoa)

By Laura Klappenbach, About.com

Australian Spotted Jellyfish (Pyllorhiza punctata).

Australian Spotted Jellyfish (Pyllorhiza punctata).

Photo © Dwight Smith / Shutterstock.
Description: Jellyfish are invertebrates (they do not have a backbone). They belong to the Phylum Cnidaria (pronounced ni*da"ri*a) which is a group of animals with the following characteristics:
  • radial symmetry
  • diploblastic (body wall consists of ectoderm and endoderm separated by a mesoglea)
  • possess nematocysts
Jellyfish experience alternation of generations in which one generation (medussa) reproduces sexually and the next (scyphistomae) reproduces asexually. The medusa form is the dominant form. The stages of a jellyfish's life cycle include:
  • egg and sperm
  • planula larva
  • scyphistoma (polyp)
  • strobilating scyphistomata (polyp hydroid colony)
  • ephyra
  • medusa
View details about the life cycle of a jellyfish →
Classification:
  • Kingdom: Animalia
  • Phylum: Cnidaria
  • Class: Scyphozoa (Source: Morris and Fautin)

New to animal classification? Find out more about how scientists classify animals.

Habitat: Jellyfish live in all oceans including Arctic and tropical seas (Source: Morris and Fautin).
Range: A few species inhabit the deep sea. Most species are common in coastal waters (Source: Morris and Fautin).
Diet: Jellyfish are carnivores. They feed on zooplankton, fish, and invertebrates. (Source: Morris and Fautin)
Sources:

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