Natures wonders: Bird Migration (Introduction)

by David Turell , Wednesday, June 15, 2016, 16:44 (2870 days ago) @ David Turell

The connection with the magnetic field may be in the retina, not in the iron fund in some spots on the birds:-https://www.washingtonpost.com/news/speaking-of-science/wp/2016/06/09/why-dont-birds-get-lost-they-may-have-mastered-quantum-mechanics/-"We think they are using quantum mechanics to navigate," said Daniel Kattnig, a researcher in the chemistry department at Oxford University. Kattnig works in a lab that studies radical pairs — a phenomenon in which atoms acquire extra electrons that are "entangled" with one another, each affecting the other's motion even though they're separated by space. It's a field of science that's difficult to understand under the best of circumstances; imagine trying to figure out it out with a bird brain.-"But according to an increasingly popular theory, birds and other animals use a radical pair-based compass to "see" the Earth's magnetic field, allowing them to undertake great migrations and daring rescues without getting lost. It's still unproven, but Kattnig and his colleagues just verified a key component: In a study in the New Journal of Physics on Thursday, they report that the timing of these subatomic interactions makes them a good candidate to explain avian navigation.-***-"Those results sent scientists on a frenzied search for animals' magneto-receptors. They discovered iron particles in the beaks of pigeons and hens, magnetite in the noses of trout, and other magnetic molecules in the ear hairs of birds.-"Subsequent research found that some of those iron molecules were in immune cells rather than sensory ones, shaking up the migration-by-magnetic-molecules theory. But animal navigation scholars already had another possible mechanism: the radical pairs that Kattnig studies.-***-"It's thought that light-sensitive proteins called cryptochromes — which have been found in the retinas of birds, butterflies, fruit flies, frogs and humans, among others — are at the center of the mystery. When light strikes the proteins, it creates radical pairs that begin to spin in synchrony; they're entangled.-"The chemical reaction lasts only for a few microseconds, but Kattnig's research shows that it's long enough for the Earth's magnetic field to modulate the quality and direction of the electrons' spin. He also found that the radical pairs become more sensitive to the magnetic field as they "relax" — that is, as they transition back to equilibrium — if you take into account outside factors like ambient temperature.-"This suggests to Kattnig and his colleagues that sensors in the bird's eyes survey the spin state of various radical pairs and then signal the results to the brain, allowing birds to more or less "see" the Earth's magnetic field as they fly through it.-"There's still years of work to be done, Kattnig acknowledged. "We need to locate the spot where the cryptochromes are responsive to magnetism," he said. "And then we need to find the interaction partners — the cascade of signals which is then following up and giving rise to the visual impression.'"-Comment: We do not naturally sense the magnetic field on Earth, nor can we tell how it is oriented without a magnetic compass, which had to be invented by humans. How did birds, coming out of dinosaurs, after learning to fly then discover this and migrate? I can't image cell communities knowing what to do if unaware! Saltation from God? Why not?