What is the body structure of cnidarians?
The body of a cnidarian consists of two cell layers, ectoderm and endoderm. The cellssurround a digestive cavity called the coelenteron (see Figure below). Cnidarians have a simple digestive system. The single opening is surrounded by tentacles, which are used to capture prey.
What are 5 characteristics of cnidarians?
The five main characteristics of cnidarians are:
- Radial symmetry.
- Diploblastic animals.
- Tissue level of organisation.
- Presence of cnidoblasts with stinging nematocysts on the tentacles.
- Polymorphism and have two body forms, i.e. polyp and medusa.
What is function of stinging cells?
Stinging cells help jellyfish catch prey because they contain organelles called nematocysts. When something brushes against a jellyfish, the nematocysts shoot out, pierce whatever they encounter, and release venom, causing what we experience as a sting.
What are the two body form characteristics of cnidarians?
Cnidarians mostly have two basic body forms: swimming medusae and sessile polyps, both of which are radially symmetrical with mouths surrounded by tentacles that bear cnidocytes. Both forms have a single orifice and body cavity that are used for digestion and respiration.
What is the characteristics of Cnidaria?
Characteristics of Cnidarians 1) They are characterized by stinging cells called Cnidoblast and a cavity called coelenterates, justifying the name Cnidaria or Coelenterata. 2) They are exclusively aquatic and marine. 3) They are radially symmetrical and diploblastic animals.
How are you going to describe the cnidarians?
Cnidarians are radially symmetrical (i.e., similar parts are arranged symmetrically around a central axis). They lack cephalization (concentration of sensory organs in a head), their bodies have two cell layers rather than the three of so-called higher animals, and the saclike coelenteron has one opening (the mouth).
Which characteristics describe cnidarians?
All Cnidaria are aquatic, mostly marine, organisms. They all have tentacles with stinging cells called nematocysts that they use to capture food. Cnidarians only have two body layers, the ectoderm and endoderm, separated by a jelly-like layer called the mesoglea. Most Cnidarians have radial symmetry.
What is the defining characteristic of cnidarians?
What is the function of stinging cells in cnidarians?
Cnidarians contain specialized cells known as cnidocytes (“stinging cells”) containing organelles called nematocysts (stingers). These cells are present around the mouth and tentacles, and serve to immobilize prey with toxins contained within the cells. Nematocysts contain coiled threads that may bear barbs.
What are the functions of Cnidaria?
Respiration and excretion in cnidarians are carried on by individual cells that obtain their oxygen directly from water—either that in the coelenteron or that of the environment—and return metabolic wastes to it. Thus, all physiological functions are carried out at no more than the tissue level of differentiation.
What are the 10 basic characteristics of cnidarians?
Characteristics of Cnidaria:
- Radially Symmetrical.
- Body multicellular, few tissues, some organelles.
- Body contains an internal cavity and a mouth.
- Two different forms exist, medusa and polyp.
- Reproduction is asexual or sexual.
- Has a simple net like nervous system.
- Has a distinct larval stage which is planktonic.
What characteristics of phylum Cnidaria are most important in distinguishing it from other phyla?
What characteristics of Phylum Cnidaria are the most important in distinguishing it from other phyla? They are sessile, radial symmetry, production of nematocysts.