Facts about cnidarians?

Fast Facts: Cnidarians

• Scientific Name: Cnidaria.
• Common Name(s): Coelenterates, corals, jellyfish, sea anemones, sea pens, hydrozoans.
• Basic Animal Group: Invertebrate.
• Size: 3/4 of an inch to 6.5 feet in diameter; up to 250 feet long.
• Weight: Up to 440 pounds.
• Lifespan: A few days to more than 4,000 years.
• Diet: Carnivore.

1. What is unique about cnidarians?
2. What is a cnidarian known for?
3. How do cnidarians eat?
4. Are all cnidarians aquatic?
5. How do cnidarians breathe?
6. How do cnidarians reproduce?
7. Are Cnidaria autotrophic or heterotrophic?
8. Do cnidarians have a brain?
9. Do all cnidarians sting?
10. Do cnidarians have organs?
11. How do cnidarians communicate?
12. Where do cnidarians get their name from?
13. Are cnidarians poisonous?

What is unique about cnidarians?

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 a cnidarian known for?

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. Fast Facts.

How do cnidarians eat?

All cnidarians are carnivores. Most use their cnidae and associated toxin to capture food, although none is known actually to pursue prey. ... The mouth opens, the lips grasp the food, and muscular actions complete swallowing.

Are all cnidarians aquatic?

Cnidarians are invertebrates such as jellyfish and corals. They belong to the phylum Cnidaria. All cnidarians are aquatic. Most of them live in the ocean.

How do cnidarians breathe?

Cnidarians don't have lungs, and even though they live in aquatic environments they don't have gills either. ... Instead of breathing, gas exchange in Cnidarians occurs through direct diffusion.

How do cnidarians reproduce?

Reproduction of Cnidarians

In general, polyps primarily reproduce asexually by budding, however, some produce gametes (eggs and sperm) and reproduce sexually. Medusae usually reproduce sexually using eggs and sperm. ... The planula then develops into a polyp that can reproduce either sexually or asexually.

Are Cnidaria autotrophic or heterotrophic?

The common characteristic to all of these animals is that they have stinging cells located, known as cnidocytes, on their tentacles. Because they belong to the animal kingdom, you can also assume that all cnidarians are multicellular and heterotrophic - meaning they must consume their food in some way.

Do cnidarians have a brain?

Cnidaria do not have a brain or groups of nerve cells ("ganglia"). The nervous system is a decentralized network ('nerve net'), with one or two nets present. They do not have a head, but they have a mouth, surrounded by a crown of tentacles. The tentacles are covered with stinging cells (nematocysts).

Do all cnidarians sting?

All Cnidarians have tentacles with stinging cells in their tips which are used to capture and subdue prey. In fact, the phylum name "Cnidarian" literally means "stinging creature." The stinging cells are called cnidocytes and contain a structure called a nematocyst.

Do cnidarians have organs?

Cnidarians are radially or biradially symmetric, a general type of symmetry believed primitive for eumetazoans. They have achieved the tissue level of organization, in which some similar cells are associated into groups or aggregations called tissues, but true organs do not occur.

How do cnidarians communicate?

Although cnidarians are essentially floating nerve nets, with no true brains, they possess ganglia to coordinate nerve messages along the body. Cnidarians lack specific response to external stimuli, such as detecting what direction a stimulus is coming from.

Where do cnidarians get their name from?

Cnidarians get their name from cnidocytes, which are specialized cells that carry stinging organelles called cnidocysts. As for the etymology, the word Cnidaria comes from the Greek word "cnidos", which means "stinging needle".

Are cnidarians poisonous?

Cnidarians are the oldest extant lineage of venomous animals. ... Utilizing specialized penetrating nematocysts, cnidarians inject the nematocyst content or “venom” that initiates toxic and immunological reactions in the envenomated organism. These venoms contain enzymes, potent pore forming toxins, and neurotoxins.