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Episode 68: Immortal, is forever, Jellyfish

Jellyfish are some of the most ancient animals on Earth. One of the most peculiar is the Immortal Jellyfish. This jellyfish theoretically can live forever due to their incredible physiology and adaptations.

Immortal Jellyfish Description

Jellyfish have existed for over 500 million years and some suspect they existed even further, maybe 700 million years ago. They are truly one of the first multicellular organisms still in existence. Species of jellyfish have survived every mass extinction event on Earth.

The physiology of the jellyfish, to include the Immortal Jellyfish, is very crude in comparison to more advanced lifeforms like us.  There are only two basic cellular layers. The outer cell layer, or epidermis, and the inner gastrodermis. Within, these animals have a basic neural net and no real organized tissues like lungs or digestive system. Jellyfish are 95% made up of water.

Jellyfish are no actual fish. They lack a backbone or any bone for that matter. The basic life cycle of a jellyfish is once the egg is fertilized, it forms a polyp which drifts down and attaches to the bottom of the ocean. This often looks like a sea urchin. Over time, small immature “medusa” form, which eventually grow into the adult form. Most adult jellyfish look like an upside down bell with many tentacles hanging down.

Jellyfish capture their prey by their tentacles and specialized cells called cnidocytes, which shoot out like a harpoon injecting their victim with venom. The Box Jellyfish is the world’s deadliest which is responsible for over 40 human deaths a year in the Philippines.


Immortal Jellyfish Facts

Almost any organized lifeform ages. As cells get older, their DNA gets shorter, and eventually stop functioning. The Immortal Jellyfish is the only lifeform that can actually reverse the aging process and go back to an immature stage. They have developed the strategy to transdifferentiate their cells and go from a medusa back to a polyp. This in turn, releases immature medusas that are identical clones to the original jellyfish.

Other facts include:

  • Potential to live forever
  • Can be killed or eaten
  • Only 4.5 mm (0.18 in) wide
  • Eat plankton, small mollusks and fish eggs
  • First found in the Medditarian and then off the coast of Japan. Now thought to be worldwide

Immortal Jellyfish Conservation

As ocean predators and other species are in decline. Overall, jellyfish are thriving and populations are exploding.

Conservation Tips

Go visit the beach. Yet, be good stewards of the environment and clean up after yourself and even volunteer to participate in a beach cleanup.

Organizations to Support

Ocean Conservancy

Be sure to check out Underdone Comics 

January 15, 2019
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