[sci.bio] Octopus....fish, reptile or what?

avi@XN.LL.MIT.EDU (Avi Weiss) (07/13/87)

I was wondering whether an octopus is a fish or a reptile? Or prehaps
some other class? Correct answers would be most appreciated!!

   thanks

      ---avi (avi @ xn.ll.mit.edu)

dd@a.UUCP (Dan Davison) (07/14/87)

In article <596@xn.LL.MIT.EDU>, avi@XN.LL.MIT.EDU (Avi Weiss) writes:
> I was wondering whether an octopus is a fish or a reptile? Or prehaps
> some other class? Correct answers would be most appreciated!!

It's a highly developed mollusc, most closely related to the cuttlefish.

dan davison Theoretical Biology, Los Alamos National Lab
dd@lanl.gov
(formerly at U of Houston)

felsenst@entropy.ms.washington.edu (Joe Felsenstein) (07/14/87)

In article <596@xn.LL.MIT.EDU> avi@XN.LL.MIT.EDU (Avi Weiss) writes:
>I was wondering whether an octopus is a fish or a reptile? Or prehaps
>some other class? Correct answers would be most appreciated!!

It's in the Phylum Mollusca, a relative of clams, snails, etc. Fish and
reptiles are in the Phylum Chordata together with us and a few others.
The correct plural of "octopus" in Greek is, I am told, "octopodes".

Now for the really interesting question: what is the butterfly: is it a
bird or a bat?   ;-)

Joe Felsenstein, Dept. of Genetics, Univ. of Washington, Seattle, WA 98195
... uw-beaver!uw-entropy!uw-evolution!joe

smitty@aeras.UUCP (Jim Smith) (07/14/87)

In article <596@xn.LL.MIT.EDU> avi@XN.LL.MIT.EDU (Avi Weiss) writes:
>I was wondering whether an octopus is a fish or a reptile? Or prehaps
>some other class? Correct answers would be most appreciated!!
>
>   thanks
>
>      ---avi (avi @ xn.ll.mit.edu)

Would you believe mollusks (like in snails, clams, squid, etc.)?

De-licious!

	You're welcome!
			Smitty

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duncan@csd4.milw.wisc.edu (Shan D Duncan) (07/14/87)

In article <234@a.UUCP> dd@a.UUCP (Dan Davison) writes:
>In article <596@xn.LL.MIT.EDU>, avi@XN.LL.MIT.EDU (Avi Weiss) writes:
>> I was wondering whether an octopus is a fish or a reptile? Or prehaps
>> some other class? Correct answers would be most appreciated!!


>
>It's a highly developed mollusc, most closely related to the cuttlefish.
>
>dan davison Theoretical Biology, Los Alamos National Lab
>dd@lanl.gov
>(formerly at U of Houston)


And...

The class is Cephalopoda ("head-foots") also along with the cuttlefish, there
are the squids and nautilus.  The class is considered to be the most
evolutionary "advanced" of the invertebrates.  Around 600 species living, all
marine-- I believe.  An interesting note---octopus show very good parental
care and squid are believed to have a "better engineered/designed" eye then
vertebrates.  A whimsical notion by J. Diamond (sp?).  If everything was
created by design---then God is a squid :-).

						Shan

bill@ut-ngp.UUCP (Bill Jefferys) (07/14/87)

In article <623@entropy.ms.washington.edu> uw-entropy!uw-evolution!joe@uw-beaver.UUCP (Joe Felsenstein) writes:
>In article <596@xn.LL.MIT.EDU> avi@XN.LL.MIT.EDU (Avi Weiss) writes:
>>I was wondering whether an octopus is a fish or a reptile? Or prehaps
>>some other class? Correct answers would be most appreciated!!
>
>It's in the Phylum Mollusca, a relative of clams, snails, etc. 

Which is, I suppose, the ultimate origin of BC's great discovery:
"Clams got legs!!!"

Bill Jefferys

baron@uhccux.UUCP (Baron Fujimoto) (07/14/87)

In article <596@xn.LL.MIT.EDU> avi@XN.LL.MIT.EDU (Avi Weiss) writes:
<I was wondering whether an octopus is a fish or a reptile? Or prehaps
<some other class? Correct answers would be most appreciated!!
<
<   thanks
<
<      ---avi (avi @ xn.ll.mit.edu)

the octopus is a mollusk, and I think is generally considered the most
intelligent of the invertebrates.

-- 

  UUCP: {backbone}!sdcvax!nosc!uhccux!baron          
  INTERNET: baron@uhccux.UHCC.HAWAII.EDU                                
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lonetto@phri.UUCP (Michael Lonetto) (07/17/87)

In article <596@xn.LL.MIT.EDU> avi@XN.LL.MIT.EDU (Avi Weiss) writes:
>I was wondering whether an octopus is a fish or a reptile? Or prehaps
>some other class? Correct answers would be most appreciated!!
>      ---avi (avi @ xn.ll.mit.edu)



The octopi, along with squids and cuttlefish, are all mollusks.  I don't
have my guide to taxonomy around so I can't be any more specific.  One
interesting sidelight to the classification is that the octopus/squid 
group has extremely well developed eyes, which show a surprising similarity
to vertebrate eyes (certainly far closer than any other invertebrate).

These animals also have very fast, complex nervous systems, once again
on a par with vertebrate systems.  Interestingly, the speed is achieved
without myelination of the nerve axons (the system used in vertebrates).
Instead, the axons are enormous in size (hence the use of the "giant" 
squid axon in neurotransmission studies.

ML
-- 

Michael Lonetto    UUCP:(allegra!phri!lonetto) 
USMAIL: Public Health Research Institute, 455 1st Ave, NY, NYioneto)S

howard@cpocd2.UUCP (07/20/87)

In article <2797@phri.UUCP> lonetto@phri.UUCP (Michael Lonetto) writes:
>These animals also have very fast, complex nervous systems, once again
>on a par with vertebrate systems.  Interestingly, the speed is achieved
>without myelination of the nerve axons (the system used in vertebrates).
>Instead, the axons are enormous in size (hence the use of the "giant" 
>squid axon in neurotransmission studies.

Even more interesting is that octopus nervous systems use neurohormones
which are catecholamines, and are very similar to adrenaline and
noradrenaline (also catecholamines).  (Nor)Adrenaline is also called
(nor)epinephrine.  The synthetic pathways are also similar, with about
as much difference between different species of octopus as there is
between some octopi and humans.  (The enzymes involved are different,
but the sequence of transformations from phenylalanine -> tyrosine ->
... -> final hormone is nearly identical to human in some species.)
Considering that this entire pathway appears to have evolved separately
from the mammalian one, the parallel is remarkable.

This leads to some curious speculations.  For example, it is quite
possible that certain catecholamine-like psychotropic drugs (mescaline,
MDA, "Ecstasy", amphetamines, ...) would "work" in octopi in a similar
manner to the way they "work" in humans.  Of course, this would be hard
to verify experimentally, since recording the subjective experience of
an octopus is a difficult matter.  The prospect of dealing with an
octopus on a bad trip must also give one pause :-O.

If there's any interest, I could dig out my paper on neurohormone
biosynthesis, but it's of ~1970 vintage, hence not entirely up to date.

-- 
	Howard A. Landman
	...!{oliveb,...}!intelca!mipos3!cpocd2!howard
	howard%cpocd2%sc.intel.com@RELAY.CS.NET
	"... precisely the opposite of what we now know to be true."

richard@gryphon.CTS.COM (Richard Sexton) (07/23/87)

	.
	.
	.
>This leads to some curious speculations.  For example, it is quite
>possible that certain catecholamine-like psychotropic drugs (mescaline,
>MDA, "Ecstasy", amphetamines, ...) would "work" in octopi in a similar
>manner to the way they "work" in humans.  Of course, this would be hard
>to verify experimentally, since recording the subjective experience of
>an octopus is a difficult matter.  The prospect of dealing with an
>octopus on a bad trip must also give one pause :-O.
>
>-- 
>	Howard A. Landman

Well, that explains why the little buggers change color and 'melt' in your
hand. (But not in your moth).


-- 
Richard Sexton
INTERNET:     richard@gryphon.CTS.COM
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          "Its too dark to put the key in my ignition..."