Cnidarians: polyp or jellyfish-shaped animals

Cnidarians are marine animals that have a simple and remarkable body structure, which makes them very easily recognizable: their body is basically a tubular bag with a mouth at one end, surrounded by tentacles specialized in asking for food.

Differences in morphology

There are two main ways that cnidarians manifest themselves: as polyps or as jellyfish. Polyps are cylindrical animals and are often sac-shaped. They have a base attached to a solid surface, such as a rock, a shell, or the dead remains of other animals. The tentacles of the polyps are short and very thin, and often branch into many parts.

On the other hand, jellyfish are umbrella-shaped animals. Its body is diametrically flattened, so its appearance is reminiscent of an umbrella. The mouth is located at the bottom of the jellyfish, while the tentacles emerge from the edges of the body. In contrast to polyps, jellyfish tentacles are usually longer and less branched.

Differences in reproduction

Another important difference between polyps and jellyfish lies in their way of reproduction. Polyps reproduce asexually, by dividing the body or by forming buds that then separate from the original organism to form new colonies of animals. On the other hand, jellyfish reproduce sexually, producing gametes that fertilize each other to give rise to new derived jellyfish.

Summary

In summary, polyps and jellyfish are two different forms of manifestation of animals belonging to the cnidarian group. Polyps are animals attached to a solid surface, with short and branched tentacles, while jellyfish are umbrella-shaped animals, with longer and less branched tentacles. Additionally, polyps reproduce asexually, while jellyfish reproduce sexually.

sample lists

Polyps

• The corals
• sea ​​anemones
• the hydras

Jellyfish

• The moon jellyfish
• The lion's mane jellyfish
• The Aurelia jellyfish

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