Just to make sure I understood it correctly… so the birds actually have 2 separate systems to sense magnetic fields, but they both use the same (or similar) kind of cells, so it is not such a miracle that two systems have evolved.
Like, maybe this kind of cells first appeared scattered in various places in the head, which already provided some sense of navigation, and later the ones in the beak and the ones in the eyes further improved, the ones in the beak better connecting to the tactile sense, the ones in the eye better connecting to the vision?
Right, but presumably sensing of magnetic cell clusters developed in one location first, probably the beak because that wouldn’t require specific pigmentation patterns. Then that structure was duplicated in the eye and developed pigments. It’s possible the genes originally came from horizontal gene transfer, maybe an endosymbiont.
Signals coming from mechanoreceptors doesn’t mean they’re perceived as a “tactile sense”. Different senses produce nerve impulses the same way; they’re just interpreted differently.
Just to make sure I understood it correctly… so the birds actually have 2 separate systems to sense magnetic fields, but they both use the same (or similar) kind of cells, so it is not such a miracle that two systems have evolved.
Like, maybe this kind of cells first appeared scattered in various places in the head, which already provided some sense of navigation, and later the ones in the beak and the ones in the eyes further improved, the ones in the beak better connecting to the tactile sense, the ones in the eye better connecting to the vision?
Right, but presumably sensing of magnetic cell clusters developed in one location first, probably the beak because that wouldn’t require specific pigmentation patterns. Then that structure was duplicated in the eye and developed pigments. It’s possible the genes originally came from horizontal gene transfer, maybe an endosymbiont.
Signals coming from mechanoreceptors doesn’t mean they’re perceived as a “tactile sense”. Different senses produce nerve impulses the same way; they’re just interpreted differently.