But the greatest jellyfish contribution to humankind must be the green fluorescent protein (GFP), a common biomarker synthesised from crystal jellies. GFP allows scientists to monitor how certain genes work in real time, and has proved invaluable in medical research, being used in well over 30,000 studies including the study of HIV and Alzheimer’s disease. As such, the scientists behind the synthesis of GFP were awarded the Nobel prize in chemistry in 2008. Jellyfish may well have started the villain, but to many scientists around the world, they have become the inadvertent hero.
Although only a few millimetres in size, and lacking the obvious characteristics of an adult, the “pancakes” are in fact tiny jellyfish. Eventually they will mature into sexually reproducing adults and begin the cycle anew (assuming they don’t reverse develop if conditions are bad).
One reason they are so common is that contrary to appearances, a body made from jelly is a very successful strategy. Gelatinous bodies have evolved independently three times and have existed, largely unchanged, for at least 500m years, surviving all five major extinction events in the Earth’s past that wiped out 99% of all life.
Each planula then develops into a polyp, a small (2mm-3mm), stationary lifeform that feeds off floating bits of plankton. These polyps reproduce asexually, forming a colony of clones. When the time is right, the clones undergo a process known as strobilation, which transforms each one into something that looks like a stack of pancakes. One by one, they are then released into the surrounding plankton.