How did dinosaurs evolve into birds?

There have been three theories about the origin of birds In 1861, the fossil of Archaeopteryx was first discovered in Germany. Archaeopteryx lived in the Late Jurassic, about 150 million years ago, and was clad in modern bird feathers and almost indistinguishable from reptiles in terms of skeletal features. The evolutionary history of birds, which began in the Late Jurassic, lasted 150 million years.

To date, only one species of Archaeopteryx has been fossilized in the Late Jurassic, making it one of the most well-known fossil species. As the ancestor of birds, Archaeopteryx has also become a breakthrough for scientists to crack the evolution of the earth in the Mesozoic Era. Among them, the conjecture about the origin of primitive birds is an important part, and many schools of thought have been formed.

But there are three main theories that are really influential in the academic world: the theory of the origin of alveolars, the theory of the origin of crocodiles, and the theory of the origin of dinosaurs. According to Zhou Zhonghe, a researcher at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, the first hypothesis was proposed by the famous South African paleontologist Robert Broom in the early 20th century.

He believes that birds originated from a primitive class of alveolar reptiles, which appeared mainly during the Triassic period. Because it is older than the dinosaurs, it is thought to be the ancestor not only of birds but also of most reptiles, including dinosaurs. Robert's reasoning is that both pterosaurs and theropods were too specialized to be direct ancestors of birds, and that some of the characteristics of dinosaurs and birds that traveled their respective evolutionary paths were irreversible.

This view prevailed for nearly half a century in the 20th century. The second hypothesis came later, in 1972 by the British scholar Alec Walker. He argues that birds and crocodiles form a monophyletic group, so this hypothesis is often referred to as the "crocodile origin hypothesis of birds".

However, more than a decade after this hypothesis was proposed, Walker himself abandoned his view in 1985 in favor of the theory that birds originated from dinosaurs. "At present, most scholars have accepted the idea that birds originated from dinosaurs, and believe that birds evolved from a branch of theropod dinosaurs ——— small individual dinosaurs. <>

Birds evolved from dinosaurs? Scientists have made another discovery, completely subverting the perception of birds!

The evolution of dinosaurs to birds:Reduced body shape (hollow bones; skull swelling; Forelimbs are getting longer and longer) - feathers grow on the surface of the body - to survive in trees to avoid injury or find food—and have the ability to glide and fly.

Applying Molecular Biology.

Methods, researchers also further ** the feather structure of a variety of primitive birds such as Confucius birds and swallow birds hundreds of millions of years ago. The results showed that the closer the bird was to the modern day, the higher the -keratin content in the feathers. More than 20 million years ago, the molecular structure of bird feathers is exactly the same as that of living birds.

Small dinosaurs resembled birds, and many of the bird-like features often disappeared as dinosaurs grew in size. However, the avian characteristics of the diliraptors were more ornithoraptors than those of other small oviraptors.

And more, which goes against the laws we previously knew.

Researchers have found that more than 90% of the mature feathers of modern birds are composed of -keratin, and the diameter of the structural fibers formed by it is only about 3 nanometers, which is the molecular structure that supports the flight of birds. Although the flight feathers of modern ornithosaur fossils also have a small amount of -keratin, they are mainly composed of -keratin.

But it was the discovery of the Giant Raptor, and the text ended with "Dinosaurs flying into the blue sky."

As the theme, it breaks the inherent impression of dinosaurs in people's minds, which is quite attractive. The article begins with a vivid presentation of the bulky, sluggish dinosaur and the light, nimble bird, two seemingly unrelated animals in the reader's mind.

Tell us that during the Mesozoic Era, one branch of the dinosaur evolved into a soaring bird, and then described the general process of this scientific discovery. It shows that in the process of evolution to birds, different dinosaur species.

The pattern of characteristic evolution and the underlying developmental mechanism of flocks are different, indicating the complexity of the evolution of avian characteristics.

This is a popular science article that mainly introduces people to scientists.

According to a hypothesis proposed by the study, birds are likely to be descendants of a small dinosaur. At the end of the 20th century, Chinese scientists were in western Liaoning.

For the first time, dinosaur fossils with preserved feather impressions have been discovered.

It provides evidence for people to imagine the evolution of dinosaurs flying into the blue sky and changing into birds.

The article not only reveals the major discoveries made by scientists in paleontological research, but also opens the door to the science of paleontology to students, arousing their strong interest in science.

The above content refers to People's Daily Online-researchers to find important molecular characteristics of dinosaurs evolving into birds.

As early as the 19th century, the British scholar Huxley noticed that dinosaurs and birds have many similarities in bone structure, and after studying a large number of dinosaur and bird fossils, scientists proposed that birds are not only related to dinosaurs, but also likely to be descendants of a small dinosaur. These arboreal dinosaurs jumped from tree to tree, landed, slowly gained the ability to glide and eventually flew autonomously, but another view is that flight did not begin with arboreal life, and some scientists believe that a feathered dinosaur that lived on the ground learned to fly while running, no matter what. Scientists believe that the dinosaurs, which could not fly, eventually became the pride of the sky, the birds.

The immediate ancestor of birds is the opinion of a small dinosaur (Ostrom, 1967), which is believed to have evolved from a pseudocrocodile to a dinosaur of dinosaurs, and then further evolved into Archaeopteryx, which evolved into a new bird.

From the specimens that have been found, it can be seen that Archaeopteryx had feathers; hindfoot toe-to-toe type; carpal metacarpal and tarsometatarsal healing; Features such as pelvic structure, clavicle, beak, mandibular joint pattern, and eyes are similar to those of birds. Archaeopteryx had alveolar teeth and a long tail with caudal vertebrae; biconcave vertebrae; forewing metacarpophalanges free and clawed; Features such as the brain, sternum, ribs, and hind limbs are similar to those of reptiles.

So Archaeopteryx is considered to be an intermediate link between reptiles and birds.

Skeletal features. For large herbivorous dinosaurs, strength was the most important requirement. Their leg bones are large and strong, large enough to bear a huge body.

At the same time, they have evolved an ingenious construct that reduces the weight of other bones without attenuating their strength.

The smaller, fast-moving dinosaurs evolved a trait that can also be seen in modern animals: thin-walled bones. The bone resembles a hollow tube, with a thin outer wall made up of heavy bone, which is much lighter bone marrow.

Fast-moving herbivorous dinosaurs, such as Oak Tree Dragon, had this thin-walled long bone. We can assume that this skeleton is meant to reduce weight and thus gain greater speed when escaping from predators.

From the early Cretaceous theropod dinosaur called "Chinese ornithosaurus", found that its structure, and birds have a great similarity, scientists also found that the Chinese ornithosaurus running speed is extremely fast, and in the process of studying the evolution of birds, scientists have also found that the ancestors of birds were not able to fly at the earliest, they also evolved from generation to generation, before finally having the ability to fly, so, scientists guess that perhaps the ancestors of birds gradually learned to fly in the process of running fast.

Modern birds evolved from a small carnivorous dinosaur of the suborder sauropods, a branch of dinosaurs. The first birds were Archaeopteryx with characteristics somewhere between dinosaurs and birds.

It is a dinosaur called Nguyen Quoc Dragon.

The evolution of dinosaurs into birds took a long time, originating in prehistoric times and lasting for hundreds of years. This process is made up of a series of evolutionary steps, each of which is part of the evolution.

First, dinosaurs began to evolve into more aerodynamically efficient animals. Their spine begins to grow longer and their muscles become stronger. Their forelimbs have become more efficient, especially when flying, and their wings and wings have become more elongated.

Their spine has also become more flexible, allowing them to better control both horizontally and vertically.

Over time, the dinosaurs' bodies also underwent some changes, with their legs becoming shorter and their wings and wing wheels getting larger, allowing them to fly more efficiently. Their ventricles have also become larger, and Yamazen has allowed them to better understand their surroundings and respond better.

Eventually, dinosaurs developed avian features, including bird-like wings, wing wheels, and beaks, elongated and effective legs, and more advanced ventricles. They have also developed more effective flying techniques that allow them to fly in different environments. These techniques also allow them to forage, reproduce, and migrate more efficiently.

As a result, dinosaurs evolved into birds through a series of evolutionary steps, in which their body structure, physiological functions, and behavioral habits underwent major changes.