Jellyfish are known for their serene nature, drifting gracefully through the ocean’s depths. But do you know that jellyfish are also the only immortal animals on Earth?
The science behind this is absolutely mind-blowing.
How is this possible?
Jellyfish belong to a group of animals called Cnidarians, and one particular species, Turritopsis dohrnii, dubbed the ‘immortal jellyfish,’ is the primary focus of this natural wonder. This tiny, transparent jellyfish, native to the Mediterranean, seems to have cracked the code of immortality. The secret to jellyfish immortality lies in their ability to transdifferentiate. Transdifferentiation is the process by which one type of cell can convert into another type of cell. In jellyfish, this process allows them to revert to their juvenile polyp stage after they have reached sexual maturity. This means that jellyfish can essentially rewind their life cycle and start over again. It’s almost like a perpetual cycle of rebirth.
Scientists are still not sure how Turritopsis dohrnii is able to transdifferentiate, but they believe that it may have something to do with its unique set of genes or a very efficient repair system that allows them to repair damaged cells and tissues.
Scientists also believe it’s related to environmental factors like temperature, nutrition, and stress. When conditions become unfavourable, the jellyfish undergo transdifferentiation as a survival mechanism.
Let’s break it down further: most animals have a lifespan that is determined by how old their cells and organs get. Humans, for example, experience a gradual decline in cell function as they age, leading to old age and eventual death. But Turritopsis dohrnii defies this natural progression.
When environmental conditions become worse, these jellyfish retract their tentacles and sink to the ocean floor, attaching themselves to a hard surface. Once they are anchored, they begin to transform into a blob-like structure, losing their specialised cells. Then, they slowly transform into tiny, free-swimming polyps, which are the youngest stage of jellyfish development. These polyps can then develop into new jellyfish, restarting the life cycle.
Though the Turritopsis dohrnii is called the ‘immortal jellyfish,’ they are not totally immortal. They can still fall sick, be eaten by predators, or other environmental hazards. Their ability to regenerate is just a strategy for surviving in their harsh world.
