Now a popular theory holds that birds are born with migration habits and travel recognition ability, which can only be explained by genetics.
The migration habits of birds are caused by the difficulty of foraging in prehistoric times. At that time, in order to find food, bird) l had to make a long journey periodically. In this way, year after year, generations, after a long evolution process, the breeding migration habits are recorded on their genetic code, and then passed down through the RNA molecule generation by generation. As a result, young birds abandoned by their parents for a long time can still successfully fly thousands of miles to the winter feeding place they have never been before without the guidance of adult birds and without any migration experience.
Scientists have done experiments with cranes. There are two kinds of crane birds living in Germany, one in the West and the other in the East. They have to move to Egypt in certain seasons. But the migration routes of the two species are not the same. The crane in the West flies over France and Spain, then across the Strait of Gibraltar, along the coast of North Africa, to Egypt, while the crane in the east goes around the end of the Mediterranean to Egypt.
The scientists transferred the eggs of the eastern crane to the nest of the Western crane, and after hatching the birds, they marked them for identification. Surprisingly, when the eastern birds grew up and moved, they did not follow their foster mother (the Western crane), but followed the eastern crane route inherent to their ancestors.
This experiment vividly shows that the migration route of crane is not simply following the results of the elders, but the instinct under the control of genetic factors.
So, how does this genetic ability come into being? Since the acquisitiveness of knowledge cannot be inherited, how can the knowledge of directional knowledge make up human genetic code? This is a big problem for geneticists.
In the study of the secrets of the flying direction of birds, it is also found that in addition to the response to the earth’s magnetic field, the use of the sun and stars for navigation and their own genetic factors, the infrared sensitivity of birds, their olfactory and echolocation systems may also play a role in the direction. However, what kind of factor directly determines that the flying birds never get lost when they travel a long distance. This mysterious and interesting mystery of biology is waiting for the modern people to solve.