RE: Vision and Evolution (A Critique of Dawkins)
August 4, 2019 at 7:58 am
(This post was last modified: August 4, 2019 at 8:03 am by John 6IX Breezy.)
(August 4, 2019 at 3:46 am)Nakara Wrote: https://www.nature.com/articles/eye2017226
A long read, but this might help you understand the subject a lil better @OP.
I found the paper to be insightful and a useful reference. However, it also mostly emphasizes the evolution of the eye rather than of vision, which is what I find problematic in Dawkins account. That being said, the paper does seem to acknowledge in parts that there is more to the story than the eye. For example, it mentions in puzzlement that Dinoflagellates have no brain; but perhaps most importantly it mentions this towards the end of the paper:
"Trichromacy requires more than the necessary visual photopigments in the cones and cone concentration; the neurologic mechanisms to interpret and compare these signals must be in place as well. This adds further evidence to the principle that the eye (and other sensory mechanisms) drives the brain and not the reverse. Either the two must evolve in tandem, or the sensory mechanism evolves first and co-opts other neurologic machinery."
That last sentence mirrors what I said in the OP (and which has been called bullocks by other users): that the eye must simultaneously evolve the neural accessories for processing and implementing the sensory information. That said, I find the alternative explanation they presented to be very interesting: "the sensory mechanisms evolves first and co-opts other neurologic machinery." The reason why this is interesting is because developmentally we see the opposite in humans. The retina emerges and extends from the brain, not the other way around.
The claim that the eye evolves first and the brain follows also makes me wonder how they believe the inverted retina that produces the blind spot emerged. In modern vertebrates this inversion is a result of, precisely, the retina emerging from the brain during development.
