Quite possibly, the oddest of all ocean creatures, these nifty Cnidaria are made of 98% water and have no brains!! Despite this, they have existed on our planet for millions of years.... They are beautiful, deadly, misunderstood and maybe even harbour the secrets to stem cell research and cell regeneration! So here are some amazing facts about the Jellyfish...
Basics:
The plural term for Jellyfish works in the same way as the plural term of fish; more than one jellyfish is jellyfish; more than one type of jellyfish, is jellyfishes! The scientific name for jellyfish is Scyphozoa and they belong to the Phylum: Cnidaria (pronounced; ni-daria) - hence my amazing alliteration in the intro ;) Other member of this phylum include, corals and anemones. The collective noun for jellyfish can be known as a; bloom, brood, fluther, smack or smuth!!
Numbers:
Jellyfish actually are, the oldest animal in the world! They pre-exist the dinosaurs (about 240 million years ago) and even the sharks (about 240 million years ago) – yes, the jellyfish is thought to have existed 500 or some say even 600 million years ago! As they have no bones, therefore leave no fossils - it is difficult to be exact.
There are more than 10,000 species of jellyfish and they come in all sizes, shapes and colours. The largest jellyfish, the Lion’s Mane Jellyfish can be as long as 36.5 meters from head to end of the tentacles. The smallest jellyfish, in contrast, is the Irukandji which is only about 1-2cm.
Ruthless and deadly!
Jellyfish are carnivorous and can feed on anything from tiny zooplankton to small fish or crustaceans – some even exhibit cannibalistic tendencies, eating other jellyfish of the same species!
Not all Jellyfish sting, but the ones that do can be deadly – and not just to their prey. Some Jellyfish, like the box jellyfish, are deadly to humans! Their stinging tentacles are so-called because they are covered in stinging cells called nematocysts. On contact with their prey, these tentacles fire out harpoons, which then release and inject their venom. This venom causes paralysis, potentially resulting in cardiac arrest and then death. Jellyfish use two steps to feed. First, the Jellyfish catch passing prey, like fish, with their stinging tentacles. The fish is caught, paralysed and then reeled in by the tentacles. The paralysed (but not dead) fish, is then passed to the oral arms, which begin to liquify and digest the poor fish!
Forever young!
Jellyfish take 2 different forms during their lifecycle; the immature polyp and the adult medusa. The lifespan of Jellyfish can vary wildly between species, from a few hours to a few years! However, there is one species of jellyfish, turritopsis dohrnii, known literally as the immortal jellyfish! This species can regenerate any and all of its cells in a process called, transdifferentiation. During this process, the jellyfish can alter their cells into their sexually immature colonial polyp state – which, in theory, can go on indefinitely. Much like the Ship of Thesus, its immortality remains up for philosophical discussion! Could they hold the key to human ageing and stem cell research...?
Brainless, Spineless and Gutless!
Jellyfish are very simple organisms. They have no brain, bones, lungs and no heart. Absorbing oxygen through their skin, they have no requirement for a circulatory system and their nervous system without a brain is rudimentary, but they can still detect light and vibrations using structures called rhopalia. Their digestive system is also lacking the basic structures; oesophagus, liver, pancreas and intestines. Instead, they use the same orifice to "eat", act as the intestines, and expel their waste - one hole does it all!
Should you pee on a Jellyfish sting?
It is a commonly believed fact that to ease the pain of a jellyfish sting, you should pee on it! However, in reality, this could make the stinging worse. It is acid that neutralises the stinging cells of the jellyfish tentacles stopping the release of the venom. A persons urine will go though phases of being both acid and alkaline. If your unlucky enough to pee on the sting while your urine is in the alkaline phase, it will actually increase the effect of the venom! Even if you do manage to pee on it while your urine is in the acidic phase, the acidity of your urine will be only slight, with a pH of maybe around 4.5. Therefore, at its best, it's effects will be only minor. We need a lower pH to have a better effect and adequately neutralise the stinging cells. This is why vinegar is used; it has a pH of around 2-3 making it a far superior choice and the approved approach - who wants to pee on themselves anyway?! Quite literally, adding insult to injury!
How do you treat a jellyfish sting?
Firstly, carefully remove any tentacles or foreign material. Rinse the area in vinegar to neutralise the stinging (or saltwater if you have no vinegar). Then, to control pain, immerse in water as hot as you can withstand (or ice water) and treat with painkillers; paracetamol and/or ibuprofen. Ultimately, avoidance is the best way; suiting up in simple long-sleeve rash guard and long pants could save you from the sting!
So, with these amazing facts about jellyfish, hopefully, you are now inspired! Maybe you will even do further research and be the one to discover their secrets of regeneration, applying them to human wound healing or how we can defy the ageing process... or maybe you will just grab an extra point at your next pub quiz!
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