Jellyfish - what's the story??

hidinginthebush

Bipolar Joe wrote: »

OK! More about their brains, because it is awesome. I guess it depends on what you consider a brain, or sentience, but I do believe that the neural net counts as a type of brain. They have a bunch of nerves which can feel, and this lets them know and do certain things, like travelling. A lot of them don't swim in the conventional sense, sort of like a controlled floating. They can detect salinity, and the flow of the tide. Every tentacle sends messages to the bell, and this tells them which direction food or rocks might be. Some of them even see! They have little things ocelli, which detects light, and that's how they know what way is up. Then you have the Cubozoa, which really do have eyes! They have 24, some of them can see points of light, some of them can even see colour! If that wasn't cool enough, they pretty much have a 360 degree view. They might have the closest thing to a brain as they're usually understood. They're pretty dumb, but they can learn through conditioning, like "This looks like this, feels like this, can not go through or eat." which can turn into "This looks like this, can not go through or eat." when it sees a rock. Unfortunately, they're also vicious, and maybe because of their intelligence, evolved to be able to swim towards prey and deliver a really, really nasty sting, which can kill you. You don't get them around Ireland a whole lot (Basically almost never.)

That is absolutely fascinating Joe. Could this then be viewed as a steppingstone on how we evolved to develop eyes? Start off being able to detect light, then gradually hone those skills?

How do jellyfish eat? Do they sting their prey then hope it floats into their body? I presume the barbs can't move food towards their mouth? And on the topic of eating, do they have stomachs? I've always kept my distance, but jellyfish seem to be pretty uniform in their makeup, there doesn't seem to be different organs throughout their body.

Please keep talking, this is brilliant! How do you know so much? Are you a zoologist or something like that?

Capt'n Midnight

You couldn't make this stuff up.

This is what happened in a Korean Nuclear power station back in '97
http://www.nti.org/facilities/6/

But it's OK because the nuclear industry learns from it's mistakes so it shouldn't happen again.

Except since then jellyfish have also taken out Nuclear power plants in
Japan http://www.reuters.com/article/2011/06/24/us-japan-nuclear-jellyfish-idUSTRE75N0Z520110624
Scotland http://www.bbc.co.uk/news/uk-scotland-edinburgh-east-fife-13971005
Florida http://www.palmbeachpost.com/news/news/jellyfish-swarm-shuts-down-st-lucie-nuclear-power-/nL2Hc/
California http://usnews.nbcnews.com/_news/2012/04/27/11432974-diablo-canyon-nuclear-plant-in-california-knocked-offline-by-jellyfish-like-creature-called-salp?lite
Israel http://www.nbcnews.com/id/43673597/ns/technology_and_science-science/t/jellyfish-invasions-force-shutdowns-separate-nuclear-plants/
South Africa http://scienceinafrica.com/wildlife/rise-jellyfish-joyride

Capt'n Midnight

at the rate we are taking fish out of the sea soon it will be just jellyfish and squid left

http://www.kpbs.org/news/2013/may/20/stung-researcher-connects-jellyfish-blooms-doomed-/
http://ens-newswire.com/2013/05/30/un-warns-of-global-shift-from-a-fish-to-a-jellyfish-ocean/

Assassin saphir

http://en.m.wikipedia.org/wiki/Southern_stingray

On holidays in Barbados last year and I was snorkeling a shallow reef. I went to stand up in the water and luckily looked down before I put my feet into the sand. Saw two eyes looking up at me. The southern stingray was so well camouflaged against the seabed only for his eyes I would have stepped on him.

April O Neill

SeaFields wrote: »

they are some sight in the water pulsating along.

Yeah, I don't like happening upon when I'm actually in the water, but they are very cool to watch from dry land or a boat.

April O Neill

*puts up hand*

Bipolar Joe, we saw moon jellyfish on the sand a few weeks ago that looked like they were evaporating. Some were really shrivelled and only the gonads remained. Is this their fate when they get washed up? Was that actually what was happening to them?

April O Neill

Rubecula wrote: »

Portugese Man'o'War is a nasty bugger but not as bad as the Box Jellyfish.

Apparently, the Portuguese Man O War isn't a jellyfish! :eek:

daddyorchips

Is it true that jellyfish are genetically immortal ?

April O Neill

greenflash wrote: »

As a kid we used to pick up the harmless four ring jellyfish and throw them at each other. We'd scoop them up by flipping over the bell in the palm of our hands then fling them.

At the beach a few weeks ago, all the kids there were running around carrying them, and as you walked down the beach all you could hear was children uttering the word "jellyfish".

April O Neill

Czarcasm wrote: »

I'd always wondered how jellyfish reproduce, but apparently they're not that far off from humans... sort of...


From Wikipedia:





So, the male puts his bell end in the females mouth...

No, just the sperm apparently. But still kinda similar.

yeahimhere

I've no idea why, as I've never had an interest in jellyfish before, but found this thread really interesting!!

I love hearing someone talk about something they really love an are knowledable about. Think the passion comes across and instantly makes the topic more interesting.

Another question Joe. Are actopus and jellyfish part of the same family? Just always thought because of the tentacles...actually that may be a stupid question...

Rubecula

Squid. octopus, nautilous and cuttlefish are all in the same family really but they are not closely related. (Molluscs I believe but without the outer shell in the case of Squid, cuttlefish and octopus)

Capt'n Midnight

Rubecula wrote: »

Squid. octopus, nautilous and cuttlefish are all in the same family really but they are not closely related. (Molluscs I believe but without the outer shell in the case of Squid, cuttlefish and octopus)

no relation between jellyfish and cephalopods
they are related to coral and sea anemones


BTW sharks are more closely related to us than to herring

Chancer3001

say whut?

sharks and herrings are both fish?

Capt'n Midnight

Chancer3001 wrote: »

say whut?

sharks and herrings are both fish?

The Nobel Prize winning biologist Stephen Jay Gould concluded after a lifetime's studying of fish that there is no such thing as a fish.

Chancer3001

Well I'll be damned. Hd a quick look at Wikipedia there.

Same to coelacanth...a fish that's more closely related to mammals than to other fish....

You learn something new every day!!

SlipperyPeople

Some cool jellyfish pictures taken from the north Atlantic

link