Cephalopod vision: How to build a better eye
Cephalopod vision: How to build a better eye
Katz P, Lyons D
Current Biology, 33, R27-R30
A summary of, and a pitch for two other papers that have appeared in Current Biology:
Cephalopod retinal development shows vertebrate-like mechanisms of neurogenesis
Francesca R. Napoli, Christina M. Daly, Stephanie Neal, Kyle J. McCulloch, Alexandra R. Zaloga, Alicia Liu, Kristen M. Koenig
Current Biology, Volume 32, Issue 23, 2022, Pages 5045-5056
Cell types and molecular architecture of the Octopus bimaculoides visual system
Jeremea O. Songco-Casey, Gabrielle C. Coffing, Denise M. Piscopo, Judit R. Pungor, Andrew D. Kern, Adam C. Miller, Cristopher M. Niell
Current Biology, Volume 32, Issue 23, 2022, Pages 5031-5044
I haven’t read those.
The summary and pitch paper draws on the Legend of the QWERTY typewriter keyboard as an analogy of why animals evolve the specific features that they do evolve. Tn this case, the feature is “camera type” eyes, with adjustable lenses, a retina and all kinds of similarities to vertebrate eyes. There is some disagreement about the QWERTY keyboard’s evolution and functionality, best exemplified by The Fable of the Keys, but drawing equivalences between economic path dependence and how biological evolution works is genius.
This paper explains how cephalopod eyes are similar to vertebrate eyes, how they’re different, as well as why. The “how they’re different” derives from embryonic development. Oddities in vertebrate embryonic development put the light receptor cells behind a layer of nerves and blood vessels, where in cephalopods, the development puts the receptor cells in front.
Apparently why they’re the same is based on very ancient genes that regulate retinal cell creation. We know they’re ancient because they’re common to vertebrates and mollusks, whose last common ancestor lived between 600 and 700 million years ago.
One of the other interesting things this article points out is that some vision computation goes on in vertebrates’ retinas. Right now, it’s not clear where the same processing goes on in cephalopod brains, but it’s not in the retina.
One thing that’s left out is that cephalopods have only one type of light receptor in their retinas, but exhibit behavior that implies color vision. Cephalopods can apparently detect polarized light, and might detect colored light via chromatic aberration
An enjoyable paper.
Katz P, Lyons D Cephalopod vision: How to build a better eye Current Biology, 33, R27-R30