What are the two forms of cnidarians?
They have a simple body consisting of a central gut cavity surrounded by tentacles. A jelly-like substance called mesoglea lies between the outer and inner layers of the body. There are two basic cnidarian body shapes: a polyp form, which is attached to a surface; and an upside-down free-floating form called a medusa.
What is Coelenterata called Cnidaria?
Coelenterata is a term encompassing the animal phyla Cnidaria (coral animals, true jellies, sea anemones, sea pens, and their allies) and Ctenophora (comb jellies). Coelenterata lack a specialized circulatory system relying instead on diffusion across the tissue layers.
Why is a jellyfish called a medusa?
A jellyfish is called a Medusa The shape of this bell is called a medusa because it looks like the evil Medusa in Greek mythology – a woman who had offended the goddess Athena who then changed her hair into snakes and made her face so hideous it turned people into stone.
Are Cnidaria and Coelenterata the same?
Cnidarian, also called coelenterate, any member of the phylum Cnidaria (Coelenterata), a group made up of more than 9,000 living species. Mostly marine animals, the cnidarians include the corals, hydras, jellyfish, Portuguese men-of-war, sea anemones, sea pens, sea whips, and sea fans.
Is not found in Coelenterata?
Sea cucumber is an echinoderm from the class Holothuroidea as it has a spiny skin. Whereas sea pen or sea feather and sea fan are the Coelenterates. Thus, the correct answer is option C.
Do polyps turn into jellyfish?
The polyps clone themselves and bud, or strobilate, into another stage of jellyfish life, called ephyra. It is this form that grows into the adult medusa jellyfish. The jellyfish sting actually comes from tiny nematocysts, or stinging cells, on the jellyfish body.
Why cnidarians are called Coelenterates because they have?
Why are Coelenterates called Cnidarians? Coelenterates are called Cnidarians because they contain specialized cells called cnidoblasts. They possess stinging structures called nematocysts.
What happens jellyfish polyps?
In the adult, or medusa, stage of a jellyfish, they can reproduce sexually by releasing sperm and eggs into the water, forming a planula. The polyps clone themselves and bud, or strobilate, into another stage of jellyfish life, called ephyra. It is this form that grows into the adult medusa jellyfish.
What are 5 examples of cnidarians?
CNIDARIA
- Anthozoa. Corals and sea anemones.
- Scyphozoa. Swimming Jellyfish.
- Staurozoa. Stalked Jellyfish.
- Cubozoa. Box jellyfish.
- Hydrozoa. Hydroids and siphonophores.
Is jellyfish a polyp or medusa?
Jellyfish have a stalked (polyp) phase, when they are attached to coastal reefs, and a jellyfish (medusa) phase, when they float among the plankton. The medusa is the reproductive stage; their eggs are fertilised internally and develop into free-swimming planula larvae.
Why cnidarians are called so?
The name Cnidaria comes from the Greek word “cnidos,” which means stinging nettle. Casually touching many cnidarians will make it clear how they got their name when their nematocysts eject barbed threads tipped with poison.
What is the coolest Cnidaria?
Staurozoa. The most rare of these types of cnidarians, staurozoans are stalked jellyfish that dwell in cold, near-shore water attached to the substrate. They appear to be upside down jellyfish, with tentacles that project upwards from their trumpet-shaped bells and a singular stalk protruding from the center.
What three features do all cnidarians share?
Cnidarians share several basic characteristics. 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.
