Why are these three types of vertebrates conquered the sky?

Review expert: Ran Hao

Well -known science writer

Soaring in the blue sky is the long -term dream of human beings. As early as 500 BC, someone tied himself to a kite, trying to overlook the earth from the sky.

In 1783, humans realized the lightweight flyer manned flight. In 1902, human beings also realized the heavily -quality flying aircraft of the energy supply. From the earliest idea of ​​flying in the air to the final realization of this dream, humans have used more than 2,000 years.

Montgolfier Brother in 1783

Painting of hot air ball manned experiment

Source 丨 Wikipedia Encyclopedia

In fact, in the four -foot animal world, there have been species that have seen the scenery on the ground from the air before humans. For the first time from the ground, the pterosaurs that appeared on the earth more than 200 million years ago from the sky overlooking the world. With the continuous evolution of species, birds and bats have also begun to fly in the sky, and they do not need to use any tools than humans.

So, how does pterosaurs, birds and bats fly?

The mystery of flying to the blue sky

Both pterosaurs, birds, or bats have wings. The structure of wings is the basis for them to fly.

According to the principle of Bernunley, in the low -speed fluid, the place with a small flow rate is strong and the place where the flow velocity is large. When the pterosaurs, birds and bats take off, the air (that is, the fluid) is cut into the upper and lower part of the wings as soon as the wings are exposed to the wings. Because the wings have a certain arc, the distance between the two parts of the upper and lower parts is different when passing through the wings.

Source ｜ en.wikiversity.org

The distance above the wings is long, the distance below the wings is short, and the time is equal. Therefore, the flow rate of the air above the wings is fast, and the flow rate below the wings is slow. The upward force is generated. It is based on the lift that generates, and pterosaurs, birds and bats can be separated from the ground and flew to the sky.

The basic principles of pterosaurs, birds, and bats are explained earlier, but in the actual flight process, there are some differences in the way of flying.

Source ｜ Interactive popularization

The wings of pterosaur (usually we call the wing membrane) are only supported by an extended finger. This structure determines that pterosaurs cannot fly at a high speed like birds.

The imagination of the wind god pterosaur on the ground

Source 丨 Wikipedia Encyclopedia

Some pterosaurs are huge, and they are very dependent on air flow during flight, which makes them leave the earth easier. Through simulation experiments, scientists speculate that pterosaurs are not fast when flying, and the flight method is relatively simple.

There are many ways to fly birds, such as fluttering wings, gliding, hovering, etc., which are related to the shape and size of the bird's wings, size, muscle strength and other factors. Generally speaking, there are 4 types of birds: oval, high -speed, large -string ratio, and large lift type with wing seams.

The oval wings are short and round. This wings are suitable for fast take -off and turning. Birds with this wings can shuttle in the forest freely. Woodpecker and magpie belong to this type.

Woodpecker Source 丨 Wikipedia Encyclopedia

High -speed wings are short and pointed, which can help birds reach a high speed and prey in the air. Hummingbirds and swallows are the representatives of this type.

Hummingbird Source 丨 Wikipedia Encyclopedia

The big string is long, narrow, and flat than the wings. It can better use the difference in wind speed to bring the birds to glide in the sky, fly over the endless sea, and the wings of the benchmarks and other sea birds are mostly this type.

Bellyman Source 丨 UNSPLASH

The wing seams of large lift -type wings can reduce air resistance to a large extent, and use thermal airflow to let the birds fly slowly on the land, which is more common in raptors such as vultures and owls.

Vulture source 丨 pixabay

The wings of bats are similar to pterosaurs, but there are 4 fingers supporting bat wings, which makes the bats of bats higher stability. Therefore, the control of the bat to the flight is higher than the pterosaur.

However, because the hind limbs are not developed and the jumping ability degrades, it is difficult for bats to take off from the ground like birds. Therefore, the take -off method of the bat is quite special -take off in an upside -down posture.

Bat Source 丨 Wikipedia

Are all relatives flying?

In the vertebrates, only pterosaurs, birds and bats really broke the ground space and flew towards the vast sky. According to biological classification, pterosaurs belong to reptiles, bats belong to mammals, and birds have evolved from dinosaurs and are tied with these two categories. Between these three are far -fate, and they have evolved their wings independently. So why do they have a similar structure and fly?

Biologists refer to this phenomenon into convergence evolution. The reason why this phenomenon occurs is probably because their ancestors have lived in the same or similar environment for a long time.

In order to adapt to the environment, the organisms will evolve a specific structure and evolve a specific function, and the similar environment makes them evolve in a similar direction, so they have similar wings and flying functions. Similar cases include the Meso -generations of Haisheng Ciming Animal Fish Dragon and Modern Dolphin Similar, Mouse and Simply digging the forelimb (front foot) with similar shapes.

Fish Dragon Fossil (top) and dolphins (bottom)

Source 丨 Wikipedia Encyclopedia

Although humans have not evolved their wings and cannot achieve independent flights. Fortunately, humans can use wisdom to study the body structure of flying animals, explore their flight mystery, and use the principles to design and manufacture various mechanical devices to achieve long -term flight dreamsEssenceThe initial probability of animals' take -off is to survive -or to avoid natural enemies or to capture prey; while human take -off is for development, to change, to break through.Regardless of the original intention, in the process of ascending the sky, whether it is pterosaurs, birds, bats, or humans, they have recorded a strong stroke in the history of the earth.

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