A jellyfish is a transparent organism with tentacles that comes to mind when we think about it. Jellyfish begin their existence as larvae, little cigar-shaped animals that scurry through the water in search of a rock or something to attach themselves to. The larva transforms into a polyp, which looks like a little sea anemone, once it is firmly in place. As the polyp clones itself, colonies of these polyps form, which means a colony can cover a whole boat dock in a matter of days. Some polyps grow into massive shrub-like plants. When the conditions are correct, these polyps bloom in large numbers, and the juvenile jellyfish that emerge from the polyp are the result of the bloom.

If the beginning of a jellyfish's existence wasn't thrilling enough, the end is much more thrilling. When the everlasting jellyfish medusa (Turritopsis dohrnii) dies, it descends to the ocean floor and decays. It’s cells then reaggregate, but not into a new medusa, but into polyps, from which new jellyfish emerge. The jellyfish has returned to an earlier stage of life to start over. This regeneration process has already been discovered in five different jellyfish species.

Cellular transdifferentiating is a term used to describe what happens to the jellyfish throughout this phase. Its cells switch from one type to another, resulting in a whole new body layout. Although immortal jellyfish are believed to have originated in the Mediterranean Sea, they are now found in oceans all over the world.
-By Bhavya Gupta (SMSMB)