A typical organism to examine in a biology rap is the hydra. The hydra belongs to a team of organisms known as cnidarians or sometimes dubbed coelenterates. This phylum likewise includes animals such as the jellyfish and also sea anemone and the organisms that make up coral reefs. The common characteristic to every one of these pets is the they have stinging cells located, recognized as cnidocytes, on your tentacles.

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Because they belong to the animal kingdom, girlfriend can likewise assume the all cnidarians space multicellular and heterotrophic - an interpretation they must consume their food in part way. Plenty of cnidarians spend their resides attached come objects wherein they wait because that fish or other organisms come swim by them and become trapped by your tentacles.

Let"s compare the main types of cnidarians. Sea anemones belong to the course Anthozoa, which equates to median "flower animal". Anemones are often really colorful and also have hundreds of tentacles that wave in the water currents if the main component of your body stays attached come a surface. They are pretty come look at, yet deadly come fish the swim too close. The fish i do not care paralyzed through the stinging cells and also eventually is pushed right into the anemone"s mouth, i beg your pardon is in ~ the center of the tentacles. The main body area has a gastrovascular cavity, i m sorry is choose a stomach, where the fish is digested.

Coral is also related come the sea anemone, despite organisms in this group tend to it is in smaller and live in colonies. Coral reefs space actually do from the skeletons the cnidarians that have construct up for numerous years. A coral reef gives a residence to numerous other s organisms, such together fish, octopus, crustaceans and also even sharks. The good Barrier Reef turn off the shore of Australia is the biggest coral reef top top the planet.

The next team of cnidarians room the Scyphozoans, or jellyfish. These pets can move openly in the water. Basically, if girlfriend imagine a sea anemone upside down, climate you have a jellyfish. In fact, because cnidarians deserve to come in 2 forms, they have names for their body plans. The ones that sit top top a surface with your tentacles pointing increase are called polyps. The ones the swim with their tentacles pointing downward are dubbed medusas. Jellyfish achieve their food in the same means as other cnidarians, by catching smaller animals with their tentacles. Unfortunately, occasionally swimmers can accidentally come into contact with a jellyfish. In most cases, the sting from your tentacles is painful come humans, however not fatal.


The last group of cnidarians is the Hydrozoans, which includes the hydra. This little organism is found in freshwater and also can conveniently be grown and also studied in a biological laboratory. That is big enough to it is in seen with the nude eye, however if you desire to see better detail, location the hydra ~ above a concave slide and also view the under a microscope. You will notification five or six tentacles surrounding the hydra"s mouth. Even under low power, you deserve to see the individual bumps on the tentacles that note the place of the cnidocytes. Like everywhere cnidarians, the hydra has actually venom within these stingers offered to capture and paralyze prey. At the bottom that the hydra is its basal disk, i m sorry secretes a difficult substance because that attaching to surfaces. The hydra have the right to still move by floating and likewise by law a properties cartwheel whereby it flips end onto that is tentacles and then pops back to its original orientation.

You might even have the ability to see the hydra eat by place a little organism, such together daphnia or brine shrimp top top the slide. When these biology swim close come the hydra, they will instantly be grabbed by the tentacles and consumed. Since the hydra go not have a separate opening because that waste, any type of material the cannot be spend is regurgitated the end of that mouth.

Cnidarians do not have a head or a brain or various other organs the we uncover familiar come animals. The is exceptional that they deserve to live, eat, and respond to their environment. Instead of a brain, their bodies have a nerve net, which is used to coordinate their movements and respond come the environment. Most cnidarians deserve to regenerate their tentacles or various other damaged body parts. In fact, lock can also grow a whole new body attached to their main body. This smaller sized version of themselves is referred to as a bud and is a form of asexual reproduction.

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Part A: - Citation. Because that each concern below, do a notation in ~ the write-up for wherein the answer is found. Usage the exact same number a the question. One the exactly answer.

1. To what kingdom carry out cnidarians belong? a. Animalia b. Porifera c. Cnidaria

2. What might a hydra eat? a. Algae b. Brine shrimp c. Jellyfish

3. I m sorry of the following remains mainly stationary, attached come surfaces? a. Jellyfish b. Sea anemone c. Hydra

4. A "bud" is formed by a hydra as a way of: a. Defense b. Swim c. Reproduction

5. Anthozoans were named such because: a. Castle looked choose flowers b. Lock were found near Anthoa c. They have actually stingers

6. I m sorry cnidarians is most most likely to be studied in a biology class? a. Jellyfish b. Sea anemone c. Hydra

7. I m sorry of the following features are typical to every cnidarians? a. Stinging cell b. Live in oceans c. Medusa body form

8. Just how does a hydra remove wastes or undigested material?a. Exits through an anus b. Regurgitated from the mouth c. Took in through the tentacles

9. Jellyfish belong to the Phylum ______ and also the course ______.a. Cnidaria, Anthozoa b. Scyphozoa, Cnidaria c. Cnidaria, Scyphozoa

10. What structure permits a jellyfish (and other cnidarians) come respond come its environment?a. Central nervous device b. Nerve net c. Gastrovascular cavity

Part B: Summarizing

11. In a solitary sentence, identify the MAIN allude of the article.

12. Create a VENN diagram of two organisms stated in the post which compares and contrasts the characteristics of each.