The hydrozoan
When the medusa the immortal jellyfish (Turritopsis dohrnii) dies, it sinks to the ocean floor and begins to decay. Amazingly, its cells then reaggregate, not into a new medusa, but into polyps, and from these polyps emerge new jellyfish. The jellyfish has skipped to an earlier life stage to begin again.
Although many species of jellyfish have some capacity to reverse aging and revert to a larval state, most of them lose this ability once they reach sexual maturity. However, Turritopsis dohrnii appears to be the only known species able to repeatedly revert back into a larval stage even after sexual reproduction.
To date, there's only one species that has been called 'biologically immortal': the jellyfish Turritopsis dohrnii.
Jellyfish are animals that possess the unique ability to regenerate body parts. A team of scientists has now revealed the cellular mechanisms that give jellyfish these remarkable 'superpowers. ' Jellyfish are animals that possess the unique ability to regenerate body parts.
The hydrozoan Turritopsis dohrnii, an animal about 4.5 millimetres wide and tall (likely making it smaller than the nail on your little finger), can actually reverse its life cycle. It has been dubbed the immortal jellyfish.
How long does the immortal jellyfish live? Potentially forever. Which gets more impressive considering these creatures have been floating through the oceans long before the dinosaurs went extinct (66 million years ago) – it's biologically possible for a single immortal jellyfish to have been alive for this entire time.
Wild species can live anywhere from a few days to decades. One species in particular, dubbed the 'Immortal Jellyfish' (Turritopsis dohrnii) may actually live forever. This jellyfish is more likely to die at the hands (or mouth) of a turtle or fish, than from old age.
Of those that do exist, the oldest-known jellyfish fossils, found in Utah, date to 505 million years ago and have enough detail to show clear relationships with some modern species of jellyfish.
Regenerating flatworms
This apparently limitless regeneration also applies to aging and damaged tissue, allowing the worms to cheat death indefinitely, according to a study at the University of Nottingham.
The percentage of genetic similarities between humans and animals does vary: chimps, 97% similar; cats, 90%; cows, 80%; mice, 75%; fruit flies, 60%, and jellyfish, 60%.
Jellyfish sting for the same reason many sharks bite, they bump into something they think might be food and try and eat it. Are jellyfish conscious? Jellyfish have no brains and therefore are not aware of their own existence. So no, while alive they are not “conscious”.
Jellyfish predate dinosaurs by hundreds of millions of years. Jellyfish don't have bones, so fossils are hard to come by. Even so, scientists have uncovered evidence these creatures have been living in our Ocean for at least 500 million years!
Never touch a jellyfish that's washed up on shore. Dead jellyfish still have venom in their tentacles that can sting on contact.
According to Hesiod's Theogony, she was one of three Gorgon sisters born to Keto and Phorkys, primordial sea gods; Medusa was mortal, while the others, Stheno and Euryale, were immortal.
Like other jellyfish, they are preyed upon by sea turtles, fish, and even larger jellyfish or sea anemones. But if a predator tries to eat them or the jelly experiences environmental stress, the transformation process is triggered and they return to early polyp stage, often unharmed.
Turritopsis dohrnii, the so-called "immortal jellyfish," can hit the reset button and revert to an earlier developmental stage if it is injured or otherwise threatened. Like all jellyfish, Turritopsis dohrnii begins life as a larva, called a planula, which develops from a fertilized egg.
Oldest living creature on Earth identified, emerging 700 million years ago. Scientists have announced that the oldest living creature on our planet is a jellyfish-like organism called a ctenophore. It evolved from the same primordial animals that humans did.
Oldest Living Marine Animals: Bowhead Whales
The result is longer lives and less tissue damage. As a result, bowheads live well into their hundreds. According to researchers, the current record holder lived for 211 years.
How big are they? They are tiny, at a maximum of 4.5mm tall and wide. Younger jellyfish have only eight tentacles and are 1mm tall, while adults can have up to 90 tentacles.
Life Span. Moon jelly adults may live mostly for more than one year in aquarium while the polyp can live up to 25 years.
“Immortal jellyfish” had mutations that preserved telomeres, or DNA sequences that protect the end of a chromosome and typically shorten with age, New Scientist writes. These differences may be key to the jellyfish's immortality.
The researchers found many of the duplicated genes among them, including some that protect and repair the jellyfish's DNA, as DNA is often eroded with age in animals. To trigger rejuvenation, the researchers put the jellyfish under stress by letting them go hungry, among other regimens.
Lifespan refers to the maximum number of years an individual can live, making lifespan unique to everyone. The longest recorded lifespan was Jeanne Calment who lived for 122 years and 5 months, making the maximum possible human lifespan 122 years and 5 months – that is, until someone outlives Calment.
Jellyfish don't feel pain in the same way that humans would. They do not possess a brain, heart, bones or a respiratory system. They are 95% water and contain only a basic network of neurons that allow them to sense their environment.