to The seasoned ears, Schiffchaff and Wheater trillings are just as signs of spring as the first rebellious crocuses. By March, these birds had returned from winter break and began to travel along the path to breeding grounds thousands of kilometers away. With centimeter accuracy. The idea of migration often reminds us of the prominent vision of vast geese herds and star tweets, but the “majority” says. Miriam ReedvogelDirector of the German Institute of Ornithology (IAR), “I move at night and myself, so no one should follow me.”
Liedvogel has been fascinated by birds since childhood and often wondered how to navigate these long journeys. She is not alone, and even Aristotle contemplates the mystery, falsely concludes that Red Start will turn into Robin over the winter. As Liedvogel points out, mobility behaviors vary and many remain unknown, but now there is sufficient data, among other theories, to rule out species transformation. Research has revealed that 95% of migrating birds migrate at night, alone and without parental guidance, so behavior must be partially inherited. These birds use the Earth’s magnetic field to find their way. At least some of the biological mechanisms that allow this can be explained through quantum mechanics.
Biophysicist Klaus Schulten came up with it Ideas are currently popular He described bird magnetic field sensing in 1978, along with his colleagues Charles Swenberg and Albert Weller at the Institute of Biophysical Chemistry in Germany. This idea depends on what happens when the electron acquires energy. A more well-known reaction may be the production of current, such as solar power devices (or solar cells) when the sun comes out, but other effects also occur. Electrons prefer to wander in pairs, but when they absorb energy, they can produce electrons that migrate from one molecule to another. At this point, both molecules that acquire molecules and molecules that donate electrons have unpaired electrons, and those molecules acquire the hippy sound term “free radicals.”
Electrons have a quantum property called “spin”, and when two free radicals are formed in this way, the spin takes on a specific arrangement that is sensitive to the magnetic field. This means that the biochemical changes that molecules undergo during the bird’s natural body processes, and the rate of these reactions, are affected by the presence of a magnetic field. Therefore, this “radical pair effect” allows birds to sense a magnetic field. However, researchers also suggest that a little of iron oxide built into the bird’s beak could do roughly the same thing, acting as a needle in a small compass. Magnetite particles are everywhere. They are in the food we eat and are carried in the air that breathes, so it is inevitable that they will enter the body’s tissues. People report finding them in birds’ heads, but not where they can enter the brain to sense magnetic fields. Furthermore, magnetite alone failed to explain the navigable behavior people observe in birds.
Peter Hoa He is a professor of chemistry at Oxford University and has studied mechanisms that could allow birds to sense magnetic fields for over 20 years, and he lists some of the evidence in support of the radical pair effect. One discovery is that it appears that the birds are less likely to feel the difference between the north and south poles of the magnetic field in the direction of the magnetic field or the equator. “It suggested that [the magnetic sensing] It wasn’t based on magnetic minerals that behave like a compass needle,” says Hoa. Place the bird in the opposite hemisphere. Still, I’m aiming to fly to the equator For warm winter weather.
Another compelling discovery is that it appears that a bird such as Robin needs light to sense a magnetic field, and is also necessary to kickstart the radical pair effect. At the quantum level, all measurements involve energy exchange. A closer look at the wavelength of light absorbed by the radical pair effect also shows that it is directed towards specific proteins. Cryptochrome 4. Schulten suggested in 2000 that there may be cryptochrome proteins. A plausible candidate To host the bird’s radical pair mechanism, Cryptochromes had just been discovered at the time, and only one was known. Liedvogel began his PhD only a few years later, and at that time began to look at cryptochrome, known for birds. She describes it as “crazy hard.” Cryptochromes 1, 2 and 4 are found in the eyes of these migratory birds, but it can be seen that the binding of cryptochromes 1 and 2 with the important light-absorbing dyes of the radical pair effect is not as strong as in Cryptochrome 4, which was discovered later.
Careful studies of the wavelengths of light absorbed by Cryptochrome 4 have revealed exactly which radicals are formed. In 2021, Hore and his colleagues were able to test the magnetic field sensitivity of Cryptochrome 4 from moving Robins and compare it to that of chickens. They showed that Robin proteins are more sensitive to magnetic fields than chicken proteins. Furthermore, mutating the candidate portion of a protein flagged as radical-forming, no magnetic field-sensitive effects were detected. All of this strongly supported the radical pair mechanism of cryptochrome 4 proteins as the basis for magnetic field sensing in birds despite small values of energy involved. The Earth’s magnetic field strength on the surface is only 50 microtesla, and standard medical MRI uses a field at least 20,000 times higher. Therefore, the amount of these interactions is small. It is one million times the thermal energy of molecules that rotate at body temperature.
With the discovery of Cryptochrome 4 and evidence in favour of the underlying pair effect, Liedvogel took another tack and set out to look for signs of adaptive choices that optimize proteins in the evolution of seasonally migrating birds. Corinna Langebrake, who had a PhD in Liedvogel at IAR, examined genome sequences of all known birds and compared the regions associated with cryptochrome production in migrating and non-middle birds. They found that there was little interspecies variation in Cryptochromes 1 and 2. This may indicate that these proteins are universally essential as changes are dangerous to survival. As Liedvogel points out, these proteins are responsible for maintaining a circadian rhythm (the “body clock”), so everything is summed up. Furthermore, they found higher levels of variation in the region of cryptochrome 4, which generates radicals in the radical pair effect as well as in the region of cryptochrome 4, which generates radicals in migrating and non-migrating birds. Also, cryptochrome 4 has other regions of apparently high selectivity, possibly pointing to the additional unknown function of proteins. But what is probably difficult to explain is that there is no Cryptochrome 4 in a group of birds, including Tyranni, an isolated, long-distance night migrant. Behavioral experiments are underway to test whether these birds can sense the Earth’s magnetic fields in the way the cryptographic four-radical pair mechanism model attempts to explain, but the ju judge has not yet been released.
Meanwhile, a paper published earlier this year suggests that, thanks to the fundamental principles of quantum mechanics, there may be limits to how evolution can evolve in terms of improving birds’ sensitivity to magnetic fields. “There are trade-offs in every aspect of physical reality,” explains Iannis Kominis, an associate professor at Crete University in Greece. An important trade-off in quantum mechanics is Heisenberg’s principle of uncertainty. This limits the way in which two variables can be accurately identified, such as energy and time. Given this mathematics and logic to a natural conclusion and the physical process takes time for it to happen, it ultimately lands on energy with a smaller amount of energy less than that. This places a fundamental limit on achievable sensitivity, as measurements must involve energy exchange. This depends on quantum devices or bird eye proteins that operate in the lab at cryogenic temperatures. Earlier this year, Cominis, along with undergraduates at the university, will be able to sought the FTIMIOS. Gkoudinakis showed there is a limit Respected in the Animal Kingdomthe sensitivity achieved with radical pair mechanisms can be very close to this limitation.
“It seems nature has devised quantum technology before us. It doesn’t seem to be that crazy, right?” Comminis says. “The opposite means that we are smarter than nature.” He also suggests that if the sensitivity achieved is not that close to the limit, there is room for quantum sensing technology to use “IP from Mother Nature, trying to make better products.”
Quantum calculations highlight potential evidence in favour of a fundamental pair effect through birds’ response to magnetic “noise.” Calculations show that radical pair electrons actually exchange between “spin” states at certain frequencies. This means that exposure to magnetic fields that fluctuate at these frequencies can lead to disorientation. “It’s not often possible to sit on a computer and do quantum mechanics calculations and predict how an animal will behave,” adds Hore.
Ten years ago, Hore worked with Henrik Mouritsen and his colleagues at Oldenburg University in Germany to show that Robin is misguided. City electromagnetic noise – Although birds were sensitive to noise levels below those the calculations suggested. Mouritsen and his colleagues are now testing the frequencies that birds have confused. So far, these have done quite well with those calculated for the radical pair mechanism, but Hoa explains that such behavioral tests are time-consuming.
Although Hore and Liedvogel note that the cases are closed, the generation data on bird behavior, the protein-radical pair effects, appear to converge to explanations of bird sensitivity to magnetic fields. If correct, it corresponds to the incredible feat of quantum sensing achieved in the messy organic environment of bird eyes, not some high-tech cryogenic labs. “I’m certainly looking at the bird in a different light,” says Hoa. “The term “bird brain” is usually a shaming. Now I consider it a compliment. ”
