yes it is that time of the week again...It is so easy to name your favourite fluffy mammal, but what about invertebrates!! There are by far more invertebrate species on this world than vertebrates (to which mammals belong too).

so what is your favourite invertebrate???

I like Patella vulgata, a sea mollusc. And if I am not mistaken a delicacy in Japan.

Originally posted by spuriousmonkey
And if I am not mistaken a delicacy in Japan.
I'm guessing you aren't mistaken, after all, what ISN'T a delicacy in japan?:rolleyes:

Anyway, the octopus takes this one hands down for me:)
They are such an interesting animal with an enormous multi-faceted array of behavioural characteristics.
Every individual seems to have different tactics in the art of survival.
Squids are awesome too but they have that cartilidge thing in them, are they still invertabrates?
:( I'm serious, I don't know...

but of course theye are invertebrates!! they are actually close relatives to my beloved Patella vulgata. They all belong to the phylum Mollusca. This phylum includes clams, oysters, squids, octopods, and snails. More than 50.000 species have been described so far.

Squids belong to the Class Cephalopoda. about 600 species are known to exist at present.


and how do i know all this?

'Invertebrate zoology', by ruppert and Barnes is one of my favorite books...

In that case I know what my favourite invertabrate is except I don't the name of it, perhaps you can help.
I saw a documentary about the architeuthis deux(sp?) once, I think it was called "in search of the giant squid" but I'm not sure, it might have been a different one. Anyway in this documentary they talked about a species of squid that was about 6 foot long, they lived in warmer waters and they were very aggressive and they hunted in packs, they were thick and stocky in build and at the time I saw them they were red(for what thats worth). They were really freakin' awesome and I never knew a squid could behave like they did. A guy went down amongst them in a steel cage and was feeding them fish and stuff and when he ran out they turned on him and ferociously attacked the cage.
For some reason I remember one biting his leg and taking a huge chunk out but that could be my imagination.
Do you have any idea what type of squid I'm talking about?

Originally posted by Dr Lou Natic
In that case I know what my favourite invertabrate is except I don't the name of it, perhaps you can help.
I saw a documentary about the architeuthis deux(sp?) once, I think it was called "in search of the giant squid" but I'm not sure, it might have been a different one. Anyway in this documentary they talked about a species of squid that was about 6 foot long, they lived in warmer waters and they were very aggressive and they hunted in packs, they were thick and stocky in build and at the time I saw them they were red(for what thats worth). They were really freakin' awesome and I never knew a squid could behave like they did. A guy went down amongst them in a steel cage and was feeding them fish and stuff and when he ran out they turned on him and ferociously attacked the cage.
For some reason I remember one biting his leg and taking a huge chunk out but that could be my imagination.
Do you have any idea what type of squid I'm talking about?


Unfortunately this book is more about the structure than behavior of invertebrates, so there isn't much about these things in here. The giant squid is definitely architeuthid…but that's the genus name so there are probably several species. I don't know about the aggressive ones, but they certainly sound very interesting and shows that we have much to learn about the world around us and especially oceanic life.

So…sorry…I don't know which squid this is…

Oh I'll get by:(
One day at a time:(

The waterbear. Funny, almost microscopic thing that lives in wet moss. 2 claws on each foot.

I like comb jellies (ctenophores...I think) Anyway, there's huge ones that live deep in the sea and they're bioluminescent. Ever seen a squid change colors? It's really amazing!

Forgive me if i sound dumb, but i am fond of Caecillians. I am not sure if they have a spine... they are amphibians.. look like translucent worms..big white worms with hairs.. :D

i like hydras. i spent a good 2 hours watching one perform a ballet for me under the scope totally forgetting what i was supposed to be doing. they're such beautiful little things.

any kind of cephalopod is cool

Dragonflies are cool, did you know they see the world in slow motion?
For their size they are so fast that everything else seems to be in slow motion, you might say "well they wouldn't see a bullet in slow motion" but they would, it would just still be going really fast. Everything is going its real speed but to the dragonfly thats slow motion, its kind of hard to explain but its true.

Originally posted by Dr Lou Natic
Everything is going its real speed but to the dragonfly that's slow motion, it's kind of hard to explain but its true. How do they differ from other fast-moving insects?

I think I know what you mean, at least applied to vertebrates. It takes something like .01 second for one synapse to fire, and it takes an average of ten sequences of synapse firings to comprise one thought. (Talk about "It's kind of hard to explain," I have no idea who made that decision.) So it's hard for us to perceive more than about ten occurrences of anything per second.

One would assume that a hummingbird, for example, would have a significantly faster cycle time.

Now dragonflies, with no central nervous system, no brain, I'm not sure how the concept applies to them, but it makes sense intuitively.

Still I wonder how they are substantively different from any other insect of the same scale.

yes...insects do have a brain....

I like squids, highly intelligent and delicious.

Originally posted by Fraggle Rocker
Where? I thought a brain was the defining component of a CNS.

I think it is actually strange to think that insects wouldn't have a brain.

but here is some shallow information:
http://www.cals.ncsu.edu:8050/course/ent425/tutorial/nerves.html

SPONGE BOB SQUARE PANTS!!! http://www.dltk-kids.com/crafts/cartoons/image/sspongebob.gif

I'd have to go with an Octopus.

Anyone have an idea what the most intelligent invertebrate is?

Originally posted by blankc
Anyone have an idea what the most intelligent invertebrate is?

see the post above yours....the octopus...

not sure which of the species is most intelligent. I don't know if there is much difference between squids and cuttlefish. Their intelligence is probably correlated to their carnivorous lifestyle and locomotor dexterity.

Nomikal fav. is the answer.

since we are speaking about squids anyway:

Super squid surfaces in Antarctic (http://news.bbc.co.uk/2/hi/science/nature/2910849.stm)

Thats absolutely amazing.
I'd love to see one in action, I can't imagine what it would be like to watch that thing hunt.

imagine being a sperm whale and having to hunt these nasty giant squids...seems spooky to me...

I was thinking the exact same thing, thats one predator-prey interaction that I really hope gets filmed somehow before I die.
A spermwhales life would be a bizarre one thats for sure, they wouldn't just have to hunt these things, they'd have to fight them, all while holding their breath and aquiring the knowledge that these squids could very well overpower and drown them at the bottom of the ocean.
And this has been going on for millions of years, awesome.
Makes me wish they would spend less money on space exploration and more money on earth exploration.

Warning! Warning! Space exploration insulted! Preparing to slap you across the face! :mad:

I stand by what I said:mad:
OR
How about more money for both explorations and less money for aiding 3rd world countries:cool:

Whats the point in having a favourite invertebrate? Do they do tricks? Will they fetch a stick? Have they the intelligence to unzip a banana? Nah, can't see me taking an invertebrate for a walk.

Dr Lou Natic,

I can go with that... though I would proffer cut backs on the military first!

Originally posted by ben nevis
Whats the point in having a favourite invertebrate? Do they do tricks? Will they fetch a stick? Have they the intelligence to unzip a banana? Nah, can't see me taking an invertebrate for a walk.

i'm sure an octopus can unzip a banana if there was something of interest in it...they can remove lids from jars after all. Can a dog do that?

Regardless, I personally don't require an organism to "work" for me in order for me to appreciate it.

Octopus are good for food, as well as squid. Squid are more viscious, but octupi have been known to crawl onto shore (they can stay about 1/2 hour out of water) and drag people back into the ocean. Also, then can climb trees (lots of sticky arms) and fall out, rip out your throat, and drag you into the ocean. But they taste good. Squid will tear you limb from limb if you swim unarmed. :m:

There was a labratory that had a octopus tank next to a lobster one, and 'mysteriously', the lobsters started going down in numbers. So the staff put up a camera and watched over night.
The octopus was opening the tank crawling out and eating the lobsters, then crawling back into its own cage after ereplacing both lids. :m:

Octopi can only go on land for short times because they need to stay moist. By the way Octopi have very short life spans: most in the wild only live for 2 years as adults! They are a lay-eggs-then-die organism, sad really.

It would be nice to capture a giant squid alive… though they need high pressures to live and they only come up the surface to die.

Fair enough my dog can't open a jar but can an octopus bark at the moon?

Originally posted by ben nevis
Fair enough my dog can't open a jar but can an octopus bark at the moon?

can your dog change colour?

well, I like most invertebrates, but I like mantis most.
The way it acts looks cute to me...

What do you mean by mantis? Praying mantis?

Originally posted by spuriousmonkey
can your dog change colour?

Better than that, mine can make YOU change color!

okay, so I'm terrible in Biology

Yep, I meant the very popular praying mantis. I thought that the word mantis directly meant that creature.....

Nudibranchs are my favorites... Just because they're pretty. I don't expect them to open jars or bark at the moon.

Favorite Invertebrate:

It's caught up in between Portunus pelagicus, the blue crab, and the barnacle.

My favourite one: polyommatus eros. http://www.guypadfield.com/erosblue.html

My least favorite invertibrate is Bill Clinton. :D
Well he is a spineless blob...

What kinda creature is that? An insect with the look of a twig?

curioucity: No, its a small, squishy, and brightly colored critter that lives in the ocean and eats jelly fish and anenomes. They then extract the poisons and store them in their own skin for defense.

so, what type of phylum the nudibranch is in?
Mollusc?
Coelenterata? (sorry, I have been really away from Biology for a year, so if the name is wrong, forgive me......)
or what?

nudibranchia

phylum mollusca

subclass opisthobranchia

order nudibranchia

Originally posted by curioucity
so, what type of phylum the nudibranch is in?
Mollusc?
Coelenterata? (sorry, I have been really away from Biology for a year, so if the name is wrong, forgive me......)
or what?

You'll find some pictures here... like I said, they are pretty.

http://www.divegallery.com/morebran.htm

They would also give you the worst sting if you were dumb enough to touch one. It would be better to pet a man-of-war. Bright colors in the natural world usually equate with a biohazard or radiation symbol.

oh, speaking about man-o-war, I remembered this odd shaped jellyfish that has a body floating on the sea-surface, while right underneath it, hordes of very long tentacles are ready to catch a fish.....
Do you know the name?

Originally posted by curioucity
oh, speaking about man-o-war, I remembered this odd shaped jellyfish that has a body floating on the sea-surface, while right underneath it, hordes of very long tentacles are ready to catch a fish.....
Do you know the name?

you mean portuguese man-o-war?

link portuguese man-o-war (http://www.tpwd.state.tx.us/expltx/eft/gulf/cspecies/manofwar.htm)

I bet yes..... the last thing I remembered bout that thing is that the name has something to do with the word 'portugese'

Those things are monsters. You should see the rashes they can dish out to the unwary and impetuous.

Speaking of outlandish jellyfish, you might also be enthralled by the vast numbers of them that strand themselves in bayous and inlets and simple coasts every season, eventually to end their unusual little invertebrate lives swept up by the uncaring tide on an indeterminate shore.

I guess that's the problem with eyeless creature....
Wait a second..... how do jellyfish sense their prey? Infrared detector? 'Drones'?

They actually have rudimentary eyes, called ocelli. Box jellyfish even have complex eyes.

Where are the eyes located? Tip of tentacles?
Also, how do the rudimentary eyes work? do they only see things as blurry?

One more thing about man-o-war: What creatures compose man-o-war? I particularly ask about the phylums.... for some reasons I doubt that man-o-war consists of merely small coelenteratas...

Originally posted by NenarTronian
Forgive me if i sound dumb, but i am fond of Caecillians. I am not sure if they have a spine... they are amphibians.. look like translucent worms..big white worms with hairs.. :D

That's Sicillians big hairy people that live in Sicily, spineless but still vertebrates. (This is just a joke for all you mafiosoes out there.)

in Hawaii, there's a sea anenome that secretes a shell on it's base for hermit crabs to occupy (anenomes benefit from mobility and picking up bits of food from hemit crab meals). This shell looks indistinguishable from mollusc shells, and, in fact, was given a genus and species name based solely on the shell before an organism was ever described. Stupid taxonomists!

There lives on Cetacea, ectoparasitic (however the parasitic nature of this organism is in question) crustaceans (Family Cyamidae). All the species in this family only live on Cetacea (no free living forms) and most species live only on single species of cetacean (obligatory species specificity). It was thought that these crustaceans sucked whale blood or at least ate whale skin, however it now appears that they are grazers feeding on diatoms and algae that live on whale skin.

There is a parasitic barnacle (Rhizocephalan: a crustacean) that lives on a species of crab that changes its secondary sex characteristics (makes males into females). Apparently parasitic barnacles are prevalent.

In the Indo-West Pacific, lives the blue ring(ed) octopus that has an accessory salivary gland in which it sequesters bacteria which secrete tetrodotoxin. Presumably this tetrodotoxin protects the octopods from predation and would account for their bright warning coloration. Many humans die yearly from blue ringed octopus bites. Interestingly, other animals which sequester this bacteria and, due to the tetrodotoxin, are dangerous to humans are poison arrow frogs and at least one puffer fish species.

I just learned about the most interesting spider.
I can't remember its name but it only lives for a year and breeds once, its babies feed off a kind of "baby food" for the first few days of life but moult and then require real food, the mother litterally sacrifices herself and presses her body onto the young ones to encourage them to eat her. Even though her instincts tell her she wants to do this their stings make her itch and she then starts trying to scratch them off, but the thousands of bites eventually overwhelm her and she is liquified by her young and slurped up.

My mother would never do that for me:(

fucking loser guys

Jolly Rodger,

I guess your asking for a thrashing? :mad:

Mr. Fetus What is a thrashing?
i'm new at this place.
please help
HELP

Main Entry: 1thrash
Pronunciation: 'thrash
Function: verb
Etymology: alteration of thresh
Date: 1588
transitive senses
...
2 a : to beat soundly with or as if with a stick or whip : FLOG b : to defeat decisively or severely ''thrashed the visiting team''
3 : to swing, beat, or strike in the manner of a rapidly moving flail ''thrashing his arms''
...

the cuttle fish.
theyr just so cute.

And Cuttly!:D

Cute and Cuttly... ehe...

Originally posted by curioucity
Where are the eyes located? Tip of tentacles?
Also, how do the rudimentary eyes work? do they only see things as blurry?

The eyes are inside the rhopalium. In cubic medusae the complex eyes may be able to form images (too bad they don't have brains to process them):
http://www.mhhe.com/biosci/pae/marinebiology/casestudies/case_09.mhtml

In other jellyfish the rudimentary eyes are just sensitive to light.

Originally posted by curioucity

One more thing about man-o-war: What creatures compose man-o-war? I particularly ask about the phylums.... for some reasons I doubt that man-o-war consists of merely small coelenteratas...

Family: Physaliidae, Order: Siphonophora, Class: Hydrozoa, Phylum: Cnidaria.

Each man of war is a colony of specialized polyps attached to a gas-filled bladder.

Thats right! I find that fascinating.
They are a colony of organisms that all have different jobs.

Which reminds me of ants, I forgot about ants, ants have to be my favourite invertabrate.
They rule this planet with an iron fist.
An ant colony is like a giant brain, chemical messages fire from ant to ant and the colony as a whole is one coordinated organism.

Colonies are interesting because they completely release the pressure of natural selection on the individual. You'll find true altruism in colony animals, they no longer consider themselves priceless, the passing on of genes is not of an individuals concern because it is the whole colony that evolves as opposed to individuals, its survival of the fittest colony so they are completely and unquestioningly willing to kamikaze themselves for the good of the colony.

Humans should have naturally been like this before they started living like a colony.
We are all screwed up because we are still selfish mammals that want to pass on our own genes more than anything else, but we try to make a civilisation, and clearly its a sloppy mess, which is understandable when you consider the traits we are missing that would be required to make a civilisation work.
Traits like those of the ants.

Originally posted by Dr Lou Natic

Colonies are interesting because they completely release the pressure of natural selection on the individual.
this is not true. it appears to be altruism and sacrificing for the good of the colony, but it is still individual selection because of inclusive fitness.

I better go fill EO wilson (aka the antman) in on this new information:rolleyes:

It is not inclusive fitness because the fit are expected to sacrifice themselves, they would be unfit to not do so, and anyway they were never born to breed.
A breeding ant is born to be a breeder and stays within the safe confounds of the colony.
UNLESS we are talking about the colony passing on its genetic material which is where natural selection steps in, the individual ants are not pressured directly by natural selection, they need to do their job well in order for the colony to be successful and spawn new colonies. Most of them aren't going to breed no matter how long they avoid death.
Doing their job well will often involve dying. Ants don't bite an anteaters nose and then run away, they clamp on so there will definately be no option but death. But these individuals clearly have not been cleansed out of the gene pool yet, why is that?
That queen will continue to pump out all sorts of individuals suited to specific tasks, few of which will resemble what their father or mother are specifically designed to do, which is breeding.

I don't even have an indepth knowledge of ants, I probably made a mistake there somewhere, what I do know is individual ants (the ones you see) are not being accounted for by ant evolution.
The ants you see can live untill the die of old age, their success at life won't lead to their quality genes being passed on because that is not their task.
Colonies evolve, individuals do not, even run of the mill cooperative pack animals aren't pressured by natural selection the same way solitary animals are.
Ants are the extreme where their individual lives have no evolutionary significance at all.

About colony...
Well yeah.... for most invertebrates colony means size matters; greater army, more chance of surviving.... s o I agree......
By the way, is it ALWAYS true that the smaller the members of the colony are, the more members are in the colony? Ants are small, and they are numerous..

Originally posted by curioucity
... is it ALWAYS true that the smaller the members of the colony are, the more members are in the colony? Ants are small, and they are numerous..

Volvox are even smaller, and there aren't more than 500 individuals in the colony. By comparison, a queen ant can lay 1000 eggs or more per day.

Originally posted by Dr Lou Natic
... Colonies evolve, individuals do not....

Actually queens are subject to evolutive pressures. Their survival depends on breeding succesful workers.

Originally posted by Dr Lou Natic
I better go fill EO wilson (aka the antman) in on this new information:rolleyes:
no need, i've spoken to him and he knows what i'm talking about, however you do not. the reason why it is still individual selection and not group selection is the amount of shared genes betwee the ants (inclusive fitness) where an individual ant's fitness is increased by sacrificing its reproducing and protecting those ants with whom it shares genes.

Originally posted by Dr Lou Natic
It is not inclusive fitness because the fit are expected to sacrifice themselves, they would be unfit to not do so, and anyway they were never born to breed.
A breeding ant is born to be a breeder and stays within the safe confounds of the colony. it appears you need to look up 'inclusive fitness.' and perhaps read Wison's book on ants. other colonial organisms like bees and termites share this same evolutionary trend (including the colonial mammal, the naked mole rat) where individuals give up reproducing for the sake of protection and care of their reproducing siblings due to inclusive fitness. some search terms 'kin selection' 'altruism' 'inclusive fitness'

So we agree and you are just refusing to admit that this obviously means that the pressures of natural selection are not on the inidividual?
The only naked mole rat who is subject to the pressures of natural selection is the male that goes on the long journey to find a new colony in which to plant his seed.
Is that not correct?
Therefore it is the colonies reproduction that is an evolutionary event.

no:

kin selection and inclusive fitness allow us (evolutionary biologists) to explain, by individual selection, what appears to be group selection (which by the way doesn't exist)

Ants and bees and other hive-type creatures are a bit of a special case for kin selection.

Kin selection is an attempt to explain altruism between dissimilar individuals, and is (in my opinion) not the strongest argument in the world. You probably share 75 percent of your genetic material with the cow that you eat, but that doesn't stop you from eating it.

Ants however, have a slightly different take on things because the workers are all parthenogenic clones of the queen. Hence the entire colony - to some extent - is an individual. When an ant dies to save the queen ant from the same colony, that's a much closer kinship than if you die to save your child, since the two share pretty much the exact same genetic code, where your child only gets half of yours.

So, evolutionary pressures on ants have to be considered in this light.

Originally posted by BigBlueHead
Ants and bees and other hive-type creatures are a bit of a special case for kin selection.
Kin selection is an attempt to explain altruism between dissimilar individuals, and is (in my opinion) not the strongest argument in the world. You probably share 75 percent of your genetic material with the cow that you eat, but that doesn't stop you from eating it. it is an excellent argument and is accepted by biologists now, your opinion notwithstanding.

you're misunderstanding the difference between sharing 'genetic material' and sharing genes. the genes are the source of the phenotype, upon which selection acts, and are only a portion of the genetic code. e.g. 2 individual humans share much greater than 99% of their genetic material, but if there is only ONE nucleotide difference at each gene, they share ZERO genes, therefore kin selection would not be relevant!

Originally posted by BigBlueHead
Ants however, have a slightly different take on things because the workers are all parthenogenic clones of the queen. Hence the entire colony - to some extent - is an individual. When an ant dies to save the queen ant from the same colony, that's a much closer kinship than if you die to save your child, since the two share pretty much the exact same genetic code, where your child only gets half of yours. bee and ant drones/workers (i.e. non-reproductive) are NOT clones of the queen! The reason hypothesized that they would forgo reproduction and sacrifice themselves for nest/hive defense is that they share 75% (on average) of their genes with their sibs (not 50% like other diploids). Its a reproductive strategy which only works because of the haplo-diploidy of the organisms.

You may want to read up more on this in Behavioral Ecology, Krebs and Davies, 1st ed.

Also try; http://www.utm.edu/~rirwin/391KinSel.htm

Apologies for the clones bit!

All the same, people have accepted kin selection a little too easily in my opinion; I am unsure whether it's reasonable to assume that an altruism gene can become fixed in a population when the beneficiary of the altruism is NOT necessarily carrying the altruism gene - hence, altruism represents a selective disadvantage when it is not prevalent in the population.

That is, everyone would be willing to take advantage of the sucker who shares their food. Whether or not the bilkers would share the altruism allele is an open question.

that's exactly why altruism doesn't exist, good point.

with kin selection, we can show why it's NOT altruism. the action which appears altruistic is not, in reality, because of the benefits recieved by saving a close relative. i.e. sacrificing oneself by saving 2 sibs (each sharing on average 50% of your genes), one loses no reproductive capacity. one gains, if one can save 3 sibs, or 6 cousins, etc.

This all leads into the theory of ESS (evolutionary stable strategy).

a character that would increase the risk of losing reproductive capabilities for the benefit of others (increasing their chance of reproduction) is not an ESS (i.e. the character would be quickly lost in the population) unless those individuals which were saved carried many or most of the characters (including the character that puts reproductive capacity at risk) of the 'altruistic' individual. This is, in general, kin selection and the theory of inclusive fitness.

Yes, but wouldn't "altruists" and "bilkers" eventually reach an equilibrium in the society? How do we get all the way to the hive? Or is that something that only happens by chance?