- Joined
- Mar 8, 2004
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- 4,884
Prompted by Tidepool_geek's description (http://www.tonmo.com/community/index.php?threads/5227/#post-72222) of a GPO that didn't like people wearing red, I just did a few google searches, curious about whether GPOs had been studied enough that the belief (e.g. Wells) that they don't have color vision was substantiated. All the evidence I got pointed to the fact that they are the canonical ceph rhodopsin source, so it is quite well understood that they have only one photopigment. However, I found a number of cool bits of information that I haven't seen here before.
Most on-topic is a paper I don't understand at all-- if anyone is a biochemist with appropriate esoteric knowledge, I could use some help with this one:
http://www.biophysj.org/cgi/content/full/80/6/2922
From my very vague understanding, though, by "spectrally silent" they mean that the chemistry they're looking at is not dependent on the spectrum of incoming light, so I think it rules out the possibility that the octo can use this aspect to somehow respond to different colors.
Moving along, there's a great overview comparison of insect vs cephalopod eyes, which is both readable to novices yet chock full of fascinating details:
http://ebiomedia.com/gall/eyes/octopus-insect.html
I also found an interesting discussion of octopuses' ability to see polarized light (and learned a bit about bees, as well, by navigating to other pages on this site):
http://www.polarization.com/octopus/octopus.html
That one's description of an experiment with cuttlefish was very interesting-- apparently, cuttles are afraid of their own reflection in a mirror, but not of their reflection in a mirror with a polarization-eliminating filter in front of it.That made me think of Righty's observation that cuttles can immediately tell males from females, even though there's no way for humans to tell-- perhaps it's obvious if you can see polarized light!
There's also an intersting paper on the difference between vertebrate and invertebrate rhodopsin that uses the GPO as the invertebrate standard, same paper in 3 formats (2 html and one pdf):
http://www.pnas.org/cgi/content/full/96/11/6189
http://pubmedcentral.com/articlerender.fcgi?artid=26857
Also, there is an abstract (but no pdf, unfortunately) describing the 3 photopigments, hence color vision, in the firefly squid at:
http://www.springerlink.com/(c0bivfqq3z4rc355zoes4cr3)/app/home/contribution.asp?referrer=parent&backto=issue,3,20;journal,78,727;linkingpublicationresults,1:400424,1
ah, but cephbase has the pdf:
http://www.cephbase.utmb.edu/refdb/pdf/4617.pdf
A short commentary on ceph eye evolution turned up, too (I think um... may have posted this earlier):
http://www.d.umn.edu/~olse0176/Evolution/octo.html
Lastly,
http://abc.zoo.ox.ac.uk/Papers/currbiol04_neotenous.pdf
which describes how a particular group of pelagic octopuses are more closely related to their benthic bretheren, but what I found particularly fascinating was the evolutionary mechanism for this-- these octos have adapted to maintain the characteristics of juveniles appropriate for planktonic life into adulthood to better suit their midwater lifestyle, so anatomically, the adults are quite different from the adults of their benthic relatives, and the close relationship is only evident comparing adult to paralarvae or, as this research did, looking at the genome. Actually, this paper's cool enough it may warrant a mention over in Fossils and History...
Most on-topic is a paper I don't understand at all-- if anyone is a biochemist with appropriate esoteric knowledge, I could use some help with this one:
http://www.biophysj.org/cgi/content/full/80/6/2922
From my very vague understanding, though, by "spectrally silent" they mean that the chemistry they're looking at is not dependent on the spectrum of incoming light, so I think it rules out the possibility that the octo can use this aspect to somehow respond to different colors.
Moving along, there's a great overview comparison of insect vs cephalopod eyes, which is both readable to novices yet chock full of fascinating details:
http://ebiomedia.com/gall/eyes/octopus-insect.html
I also found an interesting discussion of octopuses' ability to see polarized light (and learned a bit about bees, as well, by navigating to other pages on this site):
http://www.polarization.com/octopus/octopus.html
That one's description of an experiment with cuttlefish was very interesting-- apparently, cuttles are afraid of their own reflection in a mirror, but not of their reflection in a mirror with a polarization-eliminating filter in front of it.That made me think of Righty's observation that cuttles can immediately tell males from females, even though there's no way for humans to tell-- perhaps it's obvious if you can see polarized light!
There's also an intersting paper on the difference between vertebrate and invertebrate rhodopsin that uses the GPO as the invertebrate standard, same paper in 3 formats (2 html and one pdf):
http://www.pnas.org/cgi/content/full/96/11/6189
http://pubmedcentral.com/articlerender.fcgi?artid=26857
Also, there is an abstract (but no pdf, unfortunately) describing the 3 photopigments, hence color vision, in the firefly squid at:
http://www.springerlink.com/(c0bivfqq3z4rc355zoes4cr3)/app/home/contribution.asp?referrer=parent&backto=issue,3,20;journal,78,727;linkingpublicationresults,1:400424,1
ah, but cephbase has the pdf:
http://www.cephbase.utmb.edu/refdb/pdf/4617.pdf
A short commentary on ceph eye evolution turned up, too (I think um... may have posted this earlier):
http://www.d.umn.edu/~olse0176/Evolution/octo.html
Lastly,
http://abc.zoo.ox.ac.uk/Papers/currbiol04_neotenous.pdf
which describes how a particular group of pelagic octopuses are more closely related to their benthic bretheren, but what I found particularly fascinating was the evolutionary mechanism for this-- these octos have adapted to maintain the characteristics of juveniles appropriate for planktonic life into adulthood to better suit their midwater lifestyle, so anatomically, the adults are quite different from the adults of their benthic relatives, and the close relationship is only evident comparing adult to paralarvae or, as this research did, looking at the genome. Actually, this paper's cool enough it may warrant a mention over in Fossils and History...