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Brainteaser of the bird's ancestor
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In the past, human beings thought that birds evolved from creeping animals initially. Archaeopteryx is the middle offspring during this evolution. It is regarded as the ancestor of birds. Though this theory seems somewhat reasonable, many paleontologists still have some doubts about whether these creeping animals, such as lizards could have evolved into birds due to some sudden variations and natural selection. So there aroused a big argument among these experts.
During the time of newly published the Original Source of Species written by Darwin, people could not understand the idea that birds evolved from creeping animals. Until 1861, archeologists found a special biological fossil in a limestone quarry in Germany. This fossil has some remnants of wings, teeth in the mouth, claws at the top of wings, a long tail composed by many knars of tail vertebras like lizards. This fossil was called "Archaeopteryx". This discovery made so many archaeologists and the ancient biologists excited. People who held the idea of "birds evolved from lizards" got proof here.
But today this rooted idea loses its place little by little. Because American archeaologists found another bird fossil in Texas, which is 75,000,000 years older than archaeopteryx fossil and named it " Virgin bird", so virgin bird occupied the name of which is the ancestor of birds. The ancient biologists pointed out that the viewpoint of birds having evolved from creeping animals would be wrong in view of facts like above. In order to uncover the mystery of the virgin bird, we can research it based on its fossil and enter further its evolution. Regarding the original source of archaeopteryx, Mr. Pantalete from the British Museum points out that the ancestors of birds are not lizards. Archaeopteryx evolved from one member of dinosaur family. Archaeopteryx and dinosaurs have some kind of intimate relationship in species, both of them belong to groovy teeth species. Evidently there are some similarities in bones between archaeopteryx and a small-sized dinosaur named light bone dinosaur. So since last century many ancient biologists supported that the ancestor of birds is the dinosaur of this species.
The theory that birds are the offspring of dinosaurs seems difficult to accept but we can get more confidence by comparing birds and dinosaurs. They have similarities in appearance. Eg. One dinosaur named parrot dinosaur whose mouth resembles the mouths of those parrots that can speak human's language. One dinosaur named ostrich dinosaur whose feet resemble those ostriches' feet, both of them have three feet toes and are good at walking. The ostrich dinosaur has no teeth, neither have ostriches. Hadrosaur's mouth is like a duck's beak, their swimming ways are also similar. Birds have feathers clothes, the Lian dinosaur lived about 18 million years ago and also had feathers on his body. The bones of birds are hollow, saving weight for flying. Some ancient dinosaurs' bones were also hollow, scientists called this chirpy and smart dinosaur as light bone dinosaur . Both the body structure and the appearance are like birds.
In the course of finding the original source of birds, scientific argument focused on the matter of collarbone. Birds' left and right collarbones are joint with each other. V-shaped, the bottom parts are connected with each other, advanced developed, while dinosaur's collarbones had disappeared with degeneration. So those people who held the idea that birds evolved from dinosaurs further proved their idea, except that some changes happened in their collarbones during the evolution. But afterwards, scientists found some light bone dinosaurs with collarbones. After analyzing these fossils, they found that archaeopteryx and light bone dinosaur have significant similarities in bones, some of which never appeared on those groovy teeth animals. So they defeat ed the idea of "dinosaur and bird evolved from groovy teeth animals". After the discovery of virgin bird's fossil, these scientists with different viewpoints try to find new breakthrough on those virgin birds. After analyzing fossils, these ancient biologists surprisingly to find that the virgin bird was much closer to birds than archaeopteryx.
Firstly, virgin bird has a protuberant keel on its breastbone, evident and big. Most important is that it has another shoulderbone named " ". Muscles on the shoulderbone need to support wings, so most of birds have strong shoulderbones. With this feature, virgin bird resembles very much normal birds. Secondly, virgin bird's bones are hollow too, the character of bones for flying. Thirdly, apart from these similarities, virgin bird has some characters of creeping animals, such as a long tail with a hucklebone connected to the backbones, similar to some creeping animals, etc..
From above facts, we can see that we should research the birds before the appearance of virgin bird. The discovery of virgin bird eliminated the viewpoint of "birds evloved from dinosaurs".
The discovery of virgin bird's fossil provided new information for our research on birds. Still now, we scientists can not agree on who is the ancestor of birds. So we have to wait for drawing a conclusion until we find more ancient birds fossils. |
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