2025年1月24日 · Cnidarian, any member of the phylum Cnidaria (Coelenterata), a group of more than 9,000 species of mostly marine animals. The group includes corals, hydras, jellyfish, Portuguese men-of-war, sea anemones, sea pens, sea whips, and sea fans. Learn more about cnidarians in this article.

2025年1月24日 · Cnidarian - Polyp, Medusa, Tentacles: Cnidarians have two cell layers, ectoderm and endoderm (gastrodermis), with the mesoglea between them. Medusae have a more highly developed nerve net than do polyps. Respiration and excretion are carried out by …

In cnidarian (hydrozoans); Scyphozoa (scyphozoans); Anthozoa (anthozoans); and Cubozoa (cubozoans). All cnidarians share several attributes, supporting the theory that they had a single origin. Variety and symmetry of body forms, varied coloration, and the sometimes complex life histories of cnidarians fascinate layperson and scientist alike.

2025年1月24日 · Cnidarian - Symbiosis, Adaptations, Predators: Cnidarians are used for food, building material, and jewelry. Extracts from many cnidarians have medicinal properties. All the species are capable of sexual reproduction.

2025年2月7日 · Echinoderm, any of a variety of invertebrate marine animals belonging to the phylum Echinodermata, characterized by a hard, spiny covering or skin. Living species include sea lilies, sea urchins, sea cucumbers, starfishes, basket stars, and sea daisies. Learn more about echinoderms.

2025年2月1日 · Jellyfish, any planktonic marine member of the class Scyphozoa (phylum Cnidaria), a group of invertebrate animals composed of about 200 described species, or of the class Cubozoa (approximately 20 species). Learn more about the characteristics and natural history of jellyfish in this article.

The phylum Cnidaria is made up of more than 9,000 living species, mostly marine animals. Corals, jellyfish, sea anemones, and sea fans are all cnidarians.

Medusa, in zoology, one of two principal body types occurring in members of the invertebrate animal phylum Cnidaria. It is the typical form of the jellyfish. The medusoid body is bell- or umbrella-shaped.

2025年1月24日 · Cnidarian - Radial Symmetry, Polyp & Medusa: The exact relationships between the cnidarian groups are unknown. The oldest fossils were soft-bodied. Representatives of all four modern classes have been identified in the Ediacaran fauna of the Precambrian Period.

Cnidarians range in size from nearly microscopic to more than 100 ft (30 m) long and more than a ton (910 kg) in weight. There are two basic body forms: the polyp (e.g., coral ) and the medusa (e.g., jellyfish ).