coelenterate

Thân thiện

A marine biologist carefully observes a coelenterate in a clear aquarium tank.

Definition

1. Noun:
   • A marine invertebrate animal: A coelenterate is a member of a phylum of simple, mostly marine animals characterized by a soft, sac-like body with a single opening serving as both mouth and anus, and tentacles armed with stinging cells.
   • Radial symmetry: These animals exhibit radial symmetry, meaning their body parts are arranged around a central axis.
   • Two body forms: Coelenterates exist in two main structural forms: the sessile polyp (e.g., sea anemone, coral) and the free-swimming medusa (e.g., jellyfish).

Usage Examples

• Noun:
  • The jellyfish is a common example of a coelenterate.
  • Coral reefs are built by colonies of tiny coelenterates.
  • The biologist studied the stinging cells of the coelenterate.

Advanced Usage

• In scientific classification: The term "coelenterate" is an older classification that included animals now more precisely divided into the phyla Cnidaria (e.g., jellyfish, corals) and Ctenophora (comb jellies). In modern taxonomy, "Cnidarian" is often the preferred term for most animals previously called coelenterates.
  • While 'coelenterate' is still used descriptively, many texts now refer specifically to 'cnidarians'.

Variants and Related Words

• Coelenterata (n): The former phylum name encompassing these animals.
• Cnidarian (n): The modern phylum name for most animals traditionally called coelenterates (excluding comb jellies).
• Polyp (n): The typically tubular, sessile life stage of a coelenterate.
• Medusa (n): The free-swimming, bell- or umbrella-shaped life stage of a coelenterate.

Synonyms

• Cnidarian: A more precise modern synonym for most coelenterates.
• Jellyfish (for the medusa form): A common type of coelenterate.
• Sea anemone / Coral (for the polyp form): Common types of coelenterates.

Related Phrases / Terms

• Stinging cell / Nematocyst: The specialized cell on the tentacles used for capturing prey and defense, a defining feature of coelenterates/cnidarians.
• Gastrovascular cavity: The single internal cavity that functions in digestion and circulation in a coelenterate.

Học thuật

Noun

1. radially symmetrical animals having saclike bodies with only one opening and tentacles with stinging structures; they occur in polyp and medusa forms

Từ đồng nghĩa

• cnidarian