Cnidarian Fun Facts:

• The name Cnidaria comes from the Greek "Cnidos" meaning stinging nettle.
• A group of jellyfish is called a smack.
• Jellyfish can have up to 800 tentacles.
• The firing of nematocysts are the fastest reactions in the animal kingdom.
• Sea anemones are names after the Anemone Flower, and that is why the anemone is sometimes called the flower of the sea.

What type of adaptations to Cnidarians have?

Jellyfish are well-adapted to their environment with bodies that are 90% water, which helps them float around easily and not get crushed by water pressure. This adaptaion also can act as a form of camoflauge, when they look almost clear. Their stinging tentacles not only ward off predators, but also keep them warm in the freezing water so far below the surface. Their bell-like shape also helps them move through the water.

When where the first fossils of the phylum Cnidaria from?

The earliest fossil record of the Cnidarians come from about 700 million years ago.

Are Cnidarians similar to any other phylum?

The phylum most like the phylum Cnidaria is the phylum Porifera (sea sponges).

How have Cnidarians evolved over time?

Over time, Cnidarians have changed from being rooted to one place over their lifetime-like the Anthozoa class- to a type of creature that is at one point able to move around freely.

What do Cnidarians eat? What eats them?

Sea anenomes and larger jellyfish feed on small fish that pass by their stinging tentacles, but smaller jellyfish typically have a diet of plankton. The natural predators of most Cnidarians are sea turtles, fish that eat coral (ex. Parrotfish), echinoderms (ex. Starfish), and some crustaceans.

Are Cnidarians endangered?

While not many are officially endangered, the majority of Cnidarians are in some way threatened by the dustruction of coral reefs.

Where do Cnidarians live?

Cnidarians such as sea anemones primarily live in great coral reefs, near the shoreline in shallow water. Jellyfish of the Cnidarian phylum can be found in extreme depths and shallow tide pools, and some Cnidarians can survive in freshwater too.

The (typical) Cnidarian life cycle:

A hydrozoan Cnidarian, such as a Moon Jelly, starts as a fertilized egg. As a planula, or larva, it swims around and eventually plants itself on a study surface. It reaches the polyp stage and buds off of itself. Then the polyp turns into a strobola and branches out, turning eventually into an ephyra, which is a smaller and lighter version of the actual medusa. As an adult medusa, it can lay eggs and start the whole process over again.

Life cycle of a Moon Jelly Game:

http://www.neaq.org/education_and_activities/games_and_activities/online_games/jellies_game.php

How do Cnidarians reproduce?

Some Cnidarians reproduce sexually, but others are able to be female and male at the same time, so they reproduce asexally.

Can Cnidarians communicate with each other? How do they do it?

Some jellyfish of the Cnidarian phylum can communicate by different flashing lights in their bodies. Still others can release certain chemicals into the water that others of their species can pick up.

How do Cnidarians move?

By a type of jet propulsion; they suck water into their mouths and spit it out in a powerful burst.

How do Cnidarians espond to stimuli?

Cnidarians have sensitive nervous tissue that allows rapid communication between cells, enabling coordinated movement.

How do Cnidarians breathe?

Cnidarians use diffusion for respiration, excretion, and circulation.

How do Cnidarians eat?

Typically, a Cnidarian such as a sea anemone or a jellyfish eat by stinging their prey with their nematocysts, or stinging cells. They then move the prey with their tentacles to their mouth, which is located at the center of the body.

Cnidarians come from the Kingdom Animalia.
Examples of the Phylum Cnidaria:
(Class-Scyphozoa)
          (Order-Stauromedusae)
                    (Famliy-Eleutherocarpidae)
                             (Genus-Haliclystus)
                                       (Species-Halicystus auricular)

(Class-Anthozoa)

           (Order- Alcyonacea)

                     (Family- Cornulariidae)

                               (Genus- Sarcodictyon)

                                          (Species- Sarcodictyon Catenata)