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Difference Between Cnidaria and Ctenophora

Main Difference

The main difference between Cnidaria and Ctenophora is that the Cnidaria shows the radial symmetry, whereas the Ctenophora shows the bilateral symmetry.

Cnidaria vs. Ctenophora

Cnidaria is the most advance group than the ctenophore, while ctenophore is less advance than the cnidarian. Cnidarian shows more diversity than ctenophore, whereas ctenophore shows less variety than cnidaria. Cnidaria shows radial symmetry; on the other side, ctenophore shows the bilateral symmetry. Cnidaria lives in both fresh and marine water habitats, whereas ctenophore lives only in marine water habitats. Cnidaria exhibits the alternation of generations; on the opposite side, ctenophora does not present any type of alternation of generations.

Cnidaria occurs in both the medusa and polyp stages; on the flip side, ctenophora occurs only in the medusa stage. Cnidaria can be immotile or can move freely in water; on the contrary, ctenophora are motile only with the help of the comb plates. Cnidaria contains an incomplete or less developed digestive system; on the flip side, ctenophora includes a complete and highly developed digestive system. Cnidaria are the type of animals that can be unsexual or hermaphrodites; on the other side, ctenophora are the animals that are only hermaphrodites.

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Cnidaria includes five classes that are Anthozoa, Hydrozoa, Cubozoa, Scyphozoa, and Staurozoa; on the flip side, ctenophora consists of two classes only that are Tentaculata and Nuda. Cnidaria includes the type of animals that have tentacles around its mouth and have stinging structure; on the other hand, ctenophora consists of the kind of animals that have comb jellies. The examples of cnidaria are corals, jellyfish, hydra, and sea anemones; on the opposite side, the example of ctenophora is comb jellies.

Comparison Chart

CnidariaCtenophora
It includes the type of animals that have tentacles around its mouth and have a stinging structureIt consists of the kind of animals that have comb plates
Symmetry
It shows radial symmetryIt shows bilateral symmetry
Size
Small in sizeLarge in size
Advance
More advanceLess advance
Diversity
Shows more diversityShows less diversity
Habitat
It is present in both freshwater and marine habitatsIt lives only in marine habitat
Alternation of Generation
It shows alternation of generationsIt does not show alternation of generations
Polyp / Medusa
It possesses both polyp and medusa formIt possesses only medusa form
Motility
It is immotile or free-swimmingIt can swim only with the help of comb plates
Digestive system
Incomplete and less organizedComplete and organized
Unisexual / Hermaphrodite
It can be unisexual or hermaphroditeIt is hermaphrodite only
Classes
It includes five classes such as Anthozoa, Hydrozoa, Cubozoa, Scyphozoa, and StaurozoaIt consists of two categories such as Nuda and Tentaculata
Examples
Jellyfish, hydra, corals, and sea anemonesComb jellies
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What is Cnidaria?

Cnidaria is the type of phylum that contains animals having the stinging structure and has tentacles around its mouth. It also includes cnidocytes that help in capturing and killing the prey that comes near the body. It consists of both immobile organisms and free swimming in the freshwater and marine habitats.

It also contains both polyp and medusa in its body forms that form during the reproductive cycle. Cnidaria is also known as coelenterates that contain an incomplete and less developed digestive system and includes a hollow gut. It contains just one hole or opening that serves or functions as the mouth and anus.

It is the diploblastic animal that is made of two cell layers. Between these two germinal layers, there is a jelly-like substance that is known as mesoglea. The absorption of different materials occurs through the process of diffusion. The example of cnidarian includes jellyfish, hydra, corals, and sea anemones.

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What is Ctenophora?

Ctenophora is the type of phylum that contains animals having the comb plates in its structure that helps in the movement in the water. It has a body that looks like a pear. It also contains colloblasts that help in disabling and killing the prey that comes near the body. It is the motile organisms in the marine water habitat only.

It also contains the only medusa in its forms that produces during the reproductive cycle of life. It includes the bilateral symmetry and large. It consists of an entire digestive or alimentary system. It is also a diploblastic animal that contains two cell layers, but it has glass transparency. It includes the excretory pores through which the excretion of waste materials occurs. It also contains sensory organs known as the statocyte that is present in the aboral pole, whereas the mouth is present in the oral pole.

The statocyte helps in the identification of gravity. It includes only the hermaphrodites in which the male sperm and female egg is present in the same organism. Nuda and Tentaculata are the two major classes of ctenophora. The example of ctenophora is comb jelly.

Key Differences

  1. Cnidaria includes the type of animals that have a stinging structure and contain tentacles all around the mouth; on the other hand, ctenophora includes animals that contain comb jellies.
  2. Cnidaria shows the radial symmetry; on the flip side, ctenophora shows the bilateral symmetry.
  3. Cnidaria includes more diversified animals; on the opposite side, ctenophora includes less diversified animals.
  4. Cnidaria is the more advance phylum; on the other side of the coin, ctenophora is the less advance phylum than the cnidaria.
  5. Cnidaria can live in both marine and freshwater environments or habitats; on the other hand, ctenophora can live only in marine water habitats.
  6. Cnidaria can be immotile or free mobile in water, whereas the ctenophora can swim only with the help of comb plates.
  7. Cnidaria can exhibit the alternation of generations; on the flip side, ctenophora cannot exhibit alternation of generations.
  8. Cnidaria contains both polyp and medusa stages; on the opposite side, ctenophora contains only the medusa stage.
  9. Cnidaria is small in body size; on the other hand, ctenophora is large in body size.
  10. Cnidaria contains cnidocytes that can capture the prey; on the opposite side, ctenophora contains colloblasts to disable the victim.
  11. Comb plates are absent in cnidarian; on the other hand, comb plates are present in ctenophora.
  12. Cnidaria contains a less developed and incomplete digestive system; on the other hand, ctenophora includes a highly developed and complete digestive system.
  13. Cnidaria can be a hermaphrodite or unisexual; on the other side of the coin, ctenophora can only a hermaphrodite.
  14. The examples of cnidaria are hydra, corals, sea anemones, and jellyfishes; on the opposite side, the example of ctenophora is comb jellies.
  15. Cnidarian includes Anthozoa, Hydrozoa, Cubozoa, Scyphozoa, and Staurozoa as five classes; on the other hand, ctenophora includes Tentaculata and Nuda as two classes.

Conclusion

The above discussion concludes that the cnidarian and ctenophora are the two phylums. Cnidaria is the phylum that contains more diversified animals, whereas the ctenophora provides less diversifies animals.

Janet White

Janet White is a writer and blogger for Difference Wiki since 2015. She has a master's degree in science and medical journalism from Boston University. Apart from work, she enjoys exercising, reading, and spending time with her friends and family. Connect with her on Twitter @Janet__White