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Cephalopods

Posted: Mon Aug 11, 2008 16:50
by MorningWood
Image
are full of amazingness.
interesting facts:

1.Cephalopods are primarily designed to be open water hunters.

2. In the shelled cephalopods (Nautilus, Sepia and Spirula) the gas-filled chambers provide the animal with buoyancy.Changing the volume of fluid within the chambers regulates buoyancy.

3. Cephalopods swim by a water jet produced by the expulsion of water from the mantle cavity through the funnel.

4. Most living (extant) cephalopods contract the mantle wall to generate the water jet.They can do this because their shell is reduced and internal or lost completely, freeing the mantle wall for the pumping action.

5. Octopods have evolved a crawling benthic (bottom-dwelling) life-style.They use jet propulsion for long-distance swimming or escape.

6. Most cephalopods seize prey with a pair of prehensile tentacles and hold it with eight suckered arms.Octopus lack the pair of tentacles, Nautilus possess 38 non-suckered tentacles.

7. Prey is killed with a horny parrot-like beak and a pair of poison glands (modified salivary glands).The radula acts as a tongue.The digestive system is adapted to digest food rapidly.

8. Much of the anatomy and physiology of cephalopods is directly or indirectly related to their active life-style and high metabolic rate :

Secondary folded gills
No gill cilia
Closed blood-vascular system
Accessory branchial hearts
Presence of hemocyanin
Highly developed eyes
Complex behavior and nervous system
Chromatophores
Ink glands

In sexual reproduction the male uses a modified arm to transfer a spermatophore to the female.Before release, the eggs are fertilised in the oviduct or mantle cavity or in some cases from a spermatophore deposited by the male into a receptacle around the mouth of the female.The eggs are laid on substrate or scattered into the water.Development of the young is direct i.e. they hatch as miniature adults.

interesting. yes.

Re: CEPHALOPODS

Posted: Mon Aug 11, 2008 16:53
by islandhopper
If nothing else you've just reminded me that that Richard Dawkins thing on Darwin is on tonight. Thanks!

Re: CEPHALOPODS

Posted: Mon Aug 11, 2008 16:59
by humblebee
MorningWood wrote:5. Octopods have evolved a crawling benthic (bottom-dwelling) life-style.
That's not so amazing. I did the same thing years ago.

Re: CEPHALOPODS

Posted: Mon Aug 11, 2008 17:01
by MorningWood
humblebee wrote:
MorningWood wrote:5. Octopods have evolved a crawling benthic (bottom-dwelling) life-style.
That's not so amazing. I did the same thing years ago.
lord baby jesus how did you manage that?

Re: Cephalopods

Posted: Mon Aug 11, 2008 17:22
by Modern Antiquarian
I used to be really into squid, particularly giant squid. There seemed to be a bit of a giant squid overload in the last few years including the historic photography of a living specimin. I'll only get excited in them again if someone catches a truly ginormous one - the stories of sizes of beaks and sucker marks found on sperm whales suggest they can get a lot bigger than any of the bodies washed up recently.

Then there was the exciting discovery of the colossal squid, but again, although a fantastic beast its not quite on the jaw dropping scale of colossal-ness I'd be really awe struck by. I'd like to see one 100 feet long.

Now I'm much more interested in yeti and bigfoot.

Re: Cephalopods

Posted: Mon Aug 11, 2008 17:32
by MorningWood
Modern Antiquarian wrote:I used to be really into squid, particularly giant squid. There seemed to be a bit of a giant squid overload in the last few years including the historic photography of a living specimin. I'll only get excited in them again if someone catches a truly ginormous one - the stories of sizes of beaks and sucker marks found on sperm whales suggest they can get a lot bigger than any of the bodies washed up recently.

Then there was the exciting discovery of the colossal squid, but again, although a fantastic beast its not quite on the jaw dropping scale of colossal-ness I'd be really awe struck by. I'd like to see one 100 feet long.

Now I'm much more interested in yeti and bigfoot.
I'm waiting for this to turn up.
Image
the cracken lives! is the title of that piccy.

Re: Cephalopods

Posted: Mon Aug 11, 2008 19:27
by Modern Antiquarian
Wow - that pic probably only makes the thing to be about 30 feet which scientists have known examples of, and its still pretty impressive - looks more like the body proportions of a colossal squid too. My squid love has been rekindled! I believe one day soon a true giant will be discovered! I bet all those fishermen and sailors who see things like this now have mobile phone video cameras, so I 'm sure I'll get to see a real sea monster in my lifetime.

Re: Cephalopods

Posted: Mon Aug 11, 2008 19:46
by MorningWood
hopefully.

longlive the octopus, squid, and cuttlefish!

Re: Cephalopods

Posted: Mon Aug 11, 2008 22:50
by meepmeep
Okay. I'm going to have nightmares now. Shouldn't have looked at this before bedtime. I was just on my way to post in the kittycat thread. Unfortunately however, I did not know what a cephalopod was, so I decided to find out. I now regret that. All those arms and massive heads in that picture, it gives me goose bumps. Eugh.

Re: Cephalopods

Posted: Mon Aug 11, 2008 22:54
by linus
literally this is the best thread ever

how does the cephalopod doctor get paid?

sick squid an hour

sorry

Re: Cephalopods

Posted: Mon Aug 11, 2008 23:01
by alongwalkhome
meepmeep wrote:Okay. I'm going to have nightmares now. Shouldn't have looked at this before bedtime. I was just on my way to post in the kittycat thread. Unfortunately however, I did not know what a cephalopod was, so I decided to find out. I now regret that. All those arms and massive heads in that picture, it gives me goose bumps. Eugh.
I have the same problem. I find them really cool in aquariums and on nature programs, but that famous sketch has always scared the bejeebus out of me, along w/Moby Dick, and sharks. I'm gonna have nightmares now. Feck.

Re: Cephalopods

Posted: Mon Aug 11, 2008 23:04
by Concrete
linus wrote:literally this is the best thread ever

how does the cephalopod doctor get paid?

sick squid an hour

sorry
Oh, don't apologise. That's made my evening. Oh hang on, Sarah's about to show me photos of kittens; that might be better. Still, that's a good joke, innit.

Re: Cephalopods

Posted: Mon Aug 11, 2008 23:11
by linus
Concrete wrote:Oh, don't apologise. That's made my evening. Oh hang on, Sarah's about to show me photos of kittens; that might be better. Still, that's a good joke, innit.
you're very kind to me, andrew

Re: Cephalopods

Posted: Tue Aug 12, 2008 14:04
by MorningWood
Something I've come across. Thought this was a bit cutesy myself.


Captain Queeg goes into a harbor bar with his pet octopus and says 'I'll bet $50.00 that no one here has a musical instrument that this here octopus can't play.'
The people in the bar look around and someone fetches out an old mandolin. The octopus has a look, picks it up, tunes it, and starts playing a few choruses of 'Rawhide.' Captain Queeg quickly pockets the fifty bucks.
The next bar patron comes up with a trumpet. The octopus takes the horn, loosens up the keys, licks its chops and starts playing 'Stella By Starlight.' Yet another $50.00 is handed over to the smiling captain.
The bar owner has been watching all of this and disappears into the back room, returning a few minutes later with a set of bagpipes under his arm. He puts them on the bar and says to the captain and his octopus,
'Now, I'll bet you $100.00 your damn octopus can't play that!'
The octopus takes a look at the bagpipes, lifts it up, turns it over, has another look from a different angle and then starts the process over again.
Puzzled, the captain comes over to the octopus and says, 'What are you waiting around for? Hurry up and play the damn thing!'
'Play it, hell!' frowned the octopus. 'As soon as I figure out how to get her pajamas off, we're outta here!'