B
Bluetongue1
Guest
A comment on the two excerpts...
The two excerpts appear to contradict each other.
From 2. “The UVA wavelengths, which reportedly do not penetrate to the level of retinal photo receptors, suppress the ability of the pineal gland to synthesize its hormonal product [melatonin]. production.”
From 1: “Plasma melatonin levels are not significantly reduced by parietalectomy...”
Someone is clearly wrong. Are they dealing with different reptiles? How universal does make either set of results?
I am immediately suspicious of excerpt 2 for a couple of reasons. Firstly, the use of the term “reportedly” with no reference to back it up.
Secondly, I question the validity of the statement that “UVA wavelengths... do not penetrate to the level of retinal photoreceptors...” This is true in fair measure of snakes as they possess a coloured fluid that filters out ultraviolet light to protect the retina. Their colour vision is restricted in comparison to ours. However lizards and turtles have good colour vision and most possess cones that allow them to see into the ultraviolet spectrum (long wavelength UVA).
Blue
The two excerpts appear to contradict each other.
From 2. “The UVA wavelengths, which reportedly do not penetrate to the level of retinal photo receptors, suppress the ability of the pineal gland to synthesize its hormonal product [melatonin]. production.”
From 1: “Plasma melatonin levels are not significantly reduced by parietalectomy...”
Someone is clearly wrong. Are they dealing with different reptiles? How universal does make either set of results?
I am immediately suspicious of excerpt 2 for a couple of reasons. Firstly, the use of the term “reportedly” with no reference to back it up.
Secondly, I question the validity of the statement that “UVA wavelengths... do not penetrate to the level of retinal photoreceptors...” This is true in fair measure of snakes as they possess a coloured fluid that filters out ultraviolet light to protect the retina. Their colour vision is restricted in comparison to ours. However lizards and turtles have good colour vision and most possess cones that allow them to see into the ultraviolet spectrum (long wavelength UVA).
Blue