Kingdom Animalia
Phylum Cnidaria
Class Scyphozoa
Order 3
Family 21
Genus Multiple
Species 200
Niche Carnivorous
Length 0.5 inches come 16 inches, though they can prosper up come 7 feet
Weight 20-400g (0.7-14oz)
Lifespan 3 – 6 months
Social Structure Live in groups
Status The vast bulk are no endangered
Natural Habitat Ocean
Average Litter Size 100
Main food item Small fish, fish eggs, larvae, plants, and other small marine creatures
Main threats Sharks, birds, sea anemones, and tuna.

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The Basics

Jellyfish, also known as jellies, room fascinating animals that spend their lives floating in the oceans. Unlike their surname suggest, jellyfish space not really fish together they absence a backbone. In fact, these animals are actually invertebrates and also they are much more closely related to corals, sea anemones, and sea whips than fish.

These an easy animals belong come the phylum Cnidaria and also are written of 95% water! While four of the classes the belong to the phylum Cnidaria are often considered as jellyfish, true jellyfish belong come the class Scyphozoa.

Jellyfish are found in all oceans throughout the world, native tropical waters come the cold waters that the Arctic ocean, and have existed on planet for billions of year – since before the moment of the dinosaurs! some inhabit deep ocean waters, but most live near the coast.


Most types are dome-like in shape, with hanging tentacles the they use to sting and immobilize your prey. These pets have minimal control over your movement yet can move small distances by expanding and also contracting a muscle in your body.

Jellyfish are comprised of 3 layers; epidermis, mesoglea, and also the gastrodermis. The epidermis creates their outer layer which includes the nerve net. The center layer is comprised of the mesoglea which is a thick, elastic, jelly-like substance. The inner great is the gastrodermis which contains the digestive cavity, a straightforward structure the acts together both a stomach and intestines and has just one opened which acts together both a mouth and also an anus.

Unlike a most other animals, jellyfish don’t have a brain. They additionally do not have actually blood or a heart. Your nervous system which is known as a nerve net is very simple and enables them to smell, finding light, and also respond to other stimuli.

All 200 species of jellyfish exhibition radial symmetry. This way that they have actually a distinctive top and bottom, but do not have a left or right side as every one of their appendages radiate outwards indigenous a main point, rather like the spokes the a bicycle wheel.

A Mediterranean jellyfish.

Jellyfish Reproduction

Not a lot is known about the methods that the miscellaneous jellyfish types reproduce. The best-studied jellyfish belong to the genus Aurelia. These jellyfish have separate sexes and also so the adults reproduce sexually. The males release their sperm v their mouths which then enter the surrounding water. This swim to the female and also enter into her oral cavity wherein they are then able to with the eggs. When the eggs space fertilized, the fertilized egg (zygotes) move right into the oral arms wherein they invest some time developing and becoming larvae.

The larvae work out on the seafloor and are now known as polyps. The polyps then begin to bud asexually and also produce medusae which then develop into adults. Other true jellyfish types belonging to other genera might spend their lives exclusively as polyps or medusae and also not alternating between the two various life stages in the exact same way.

Jellyfish go through multiple life stages.

Fun Facts about the Jellyfish!

Jellyfish are one of the oldest pets on Earth and also have readjusted very little from their primitive ancestors. These fascinating creatures have actually been learned by scientists for decades, increasing our understanding of the organic adaptations that have permitted them to persist in the world’s seas for so long. Let’s take it a closer look!

Jellyfish Sting

Jellyfish are recognized for their sting! These animals have tentacles that have tiny sting cells on them referred to as cnidocytes. These cells have tiny frameworks inside them that are full of venom, referred to as nematocysts. Once something touch a jellyfish this nematocysts shoot out and also can pass through the skin of the animal. The jellies use this device to aid capture food or together a defense system when they feeling threatened.

Like many venomous animals, the jellyfish inject your venom to cause pain and also irritation. Jellyfish venom includes a kind of protein referred to as a porin i beg your pardon is responsible because that the pain caused by their sting. This protein is no only uncovered in the gift of every jellyfish but additionally in their relatives, consisting of corals and anemones.

Humans can additionally be stung by jellyfish i beg your pardon can result in mild symptoms such as pain and blistering, to an ext serious symptoms consisting of whole-body illness. In part cases, stings can also be life-threatening.


Many jellyfish varieties have the capability to create their own light, in a procedure known together bioluminescence. This irradiate is used generally as a form of communication in between animals and also can be provided for defense, offense, and also intraspecific communication. The greatest diversity in jellyfish bioluminescence wake up in depths water, where nearly every kind of jellyfish is luminescent and is greatly used in defense against predators.

The irradiate is created by a chemical reaction in between a chemistry substance dubbed luciferin and oxygen indigenous the environment. This reaction release energy and as a result, irradiate is emitted. One enzyme dubbed luciferase helps this reaction occur. For an pet to emit light frequently they must continually bring brand-new luciferin right into their system. Some animals acquire it v their diet while others can create their own.

Bioluminescence is discovered in many marine organisms including approximately 1500 types of fish! Some types of sea stars, crustaceans, worms, and sharks are likewise luminescent.

Moon jellyfish were sent into space by scientists who wanted to understand just how they would certainly respond come microgravity.

Jellyfish in Space

Jellyfish are so cool lock have even traveled right into space! In 1991, part moon jellyfish to be sent into outer an are on plank the room Shuttle Columbia. This mission to be a study carried out by researchers to understand exactly how microgravity influenced them.

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While in space, the number of jellyfish multiplied. Top top their return to Earth, the scientists examined these space-born animals and also discovered that unlike Earth-born jellies, lock couldn’t figure out exactly how to attend to gravity.

Scientists have actually sent a number of animals into room including monkeys, dogs, ants, cats, frogs, and fruit flies!