Squid eyes, human eyes, and evolution

I just found this while investigating searching for this thread:

http://genome.cshlp.org/content/14/8/1555.full

These guys seem to think genetics shows that ceph and human eyes share a lot more gene expression than would be consistent with convergent evolution, so the last common ancestor must have had some sophisticated eye gene expression.
 
Just as an aside, I have a question realted to cephalopod eyes, does anyone have any views on how fast cephalopods adapt their retina morphology to different environmental conditions, such as culturing eggs in complete darkness and comparing these to eggs cultured in normal conditions, would the development time be long enough for there to be a morphological difference if eggs were exposed to these different conditions from the time at which they were laid until they hatch?
 
Rachael;144976 said:
Just as an aside, I have a question realted to cephalopod eyes, does anyone have any views on how fast cephalopods adapt their retina morphology to different environmental conditions, such as culturing eggs in complete darkness and comparing these to eggs cultured in normal conditions, would the development time be long enough for there to be a morphological difference if eggs were exposed to these different conditions from the time at which they were laid until they hatch?

What aspect of retinal morphology did you have in mind? I have a reference somewhere about octopuses adapting to dark conditions by migration of pigment in their photoreceptors, which happens on a timescale of minutes. I'll try to find it when I get home tonight. It sounds like you're more interested in permanent developmental changes in the retinal, though, which I have no idea about, I'm afraid.

A google scholar search found this paper:

http://jeb.biologists.org/cgi/reprint/185/1/1.pdf

which probably has the one I have in its bibliography, and might be good reading is the screening pigment is of interest.

edit: The paper I had at home is J.Z.Young 1963 Light- and Dark- Adaptation in the Eyes of Some Cephalopods Proceedings of the Zoological Society of London vol 140 part 2 March 1963 p.255
 
Thanks Monty for the paper by Gleadall, I havent read this before, so will enjoy reading it as I am interested in anything related to vision in cephalopods.

I was thinking more permanent developmental changes, such as differences in the thickness of the outer and inner segment, also whether the components found within each segment vary for different treatments. I did a project on this for my undergraduate dissertation, my results suggested that there could be a difference between the retina morphology from different conditions, but I could not conclusively say there was due to such a small sample size and the differences in sample orientation. Hopefully I will be able to continue this project for my masters and be able to determine if there is a difference. I was just curious on peoples opinions on the rate of developmental changes, and if it would be possible to adapt in such a short time.
 
While you are thinking about experimenting with light exposure during development of the eggs :gigas: If you had in mind seeing if a nocturnal species could become diurnal or crepuscular if exposed to light during incubation the mercatoris would be an easy animal to raise (relatively speaking). These nocturnals never adjust to daylight and I have always thought that it was because of their eyes (anecdotal hobbiest observations at best). This animal is not in short supply, lives 8-13 months and would make it possible to create a supply of aquarium bred, small octos for the hobbiest if they could be developped to forage during the day.
 
this is Convergent evolution, common needs have common answers ( sometimes the answers are very close, sometimes different ways for the same result).

for example : if you need having 3d perception based on light perception ... you need at least two light captors ( or two captor groups )... you can find it on invertebrates or vertebrates.

Sometime species have to use the means they have, mammals ( and reptiles) have no gills so to readapt to sea it was more "easy" to have better apnoea abilities.

Fish forms and dolphin forms ( including sometime color) are not so differents....because speed in water need hydrodynamic form, but even squids have hydrodynamic form but not the same way.
 

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