Hello, everybody! Today, I'm talking about a rather paradoxical creature... Let's start! (And sorry for being late!)
They live in every ocean, from the surface to the deep. An individual is called a medusa. They sting their prey. I am, of course, talking about jellyfish! Let's start off with an interesting fact about them: they have no blood, no brain and no gills. So let's look at how they solve these problems!
First off is getting oxygen. This one is simple: their skin is so thin that they breathe through it.
The thing with having no brain is that it doesn't necessarily mean no neurons. Jellyfish still have neurons - it's just that they're not really concentrated in one area like in our brains. They also have nerves (so they can USE their neurons.)
And not having any blood is related to not having any gills. Since they breathe through their skin, jellyfish don't need blood to transfer oxygen throughout the body - they just breathe near the organs... as strange as that sounds.
Some jellyfish have organs similar to eyes. They have the same purpose - but they aren't nearly as detailed as ours. Although some, like the deadly box jellyfish, have proper eyes and can see (the box jellyfish has 24 eyes. Two of them sense colour. Also, their eyes are on stalks.)
There are four classes of jellyfish: hydrozoans - the tons-of-individual-animals animals, stauromedusae - the stalked jellyfish, cubozoans - the box jellyfish and scyphozoans - the true jellyfish (kind of like how Aloe vera is the 'true aloe'.)
Jellyfish begin their life as polyps, small stalks with mouths that feed all the time. This stage can last for years before the jellyfish grows again.
Then it becomes a medusa - the pulsating, swimming, stinging creature that most simply cal a jellyfish.
Jellyfish can be immortal (to some extent) - it's true! Take, for example, Turritopsis dohrnii. It has actually gained the common name of the immortal jellyfish! When threatened. or if food becomes scarce, it reverts to the polyp stage and waits for things to get better. In theory, they could live forever! ...In practise, they get eaten. Nevertheless, their ability to do such a thing is quite an amazing feat!
I just want to say hi to my mum's friend Donna, who we went to see (while she and her family were camping) on Friday! She's really funny and one of my mum's best friends. So hi, Donna!
Anyway, I'll see everyone tomorrow for some more Pokémon Sun and Moon news! Bye for now!