The meteorite impact 60 million years ago destroyed the dinosaurs. Why did not destroy the birds?

Many of the once -existed birds are extinct, but some still survive.

The fossils of the White Cymbicus (top) and the digital reconstruction map of its brain (below)

About 66 million years ago, a small asteroid that killed dinosaurs collided with the earth and caused a series of events: shock waves, wildfires, sour rain, tsunami, volcanic eruption, and similar to the nuclear winter (translator Note: When a large number of nuclear weapons is a large number of nuclear weapons, Used, a large number of smoke and smoke will enter the terrible phenomenon of the atmosphere of the earth and lead to cold weather). This led to about 80%of species death. But strangely, some dinosaurs survived. They are birds.

Why do some birds live and others go to death? A new study on the skull of ancient birds shows that the survivor of this catastrophe has a larger front brain (the front area of ​​the brain).

We don't know how the larger front brain helps birds to survive, because the front brain has many different functions. Chief researcher at the study, PhD Torres, a doctoral student at the Department of Comprehensive Biology at the University of Texas University, said in an email: "This (front brain) is likely to be related to the plasticity. Class can change your behavior faster to adapt to changes in the environment. "

The research was published online on July 30 in the "Scientific Progress" magazine, and was published online at the annual meeting of the vertebrate Poetry Poor Poor Society on November 2.

Bird's brain

The bones of the birds are fragile and rarely can be completely three -dimensional petrochemical. This means that scientists have hardly observed the brains of ancient birds. But a few years ago, researchers discovered a well -preserved, some three -dimensional fish and bird fossils in a rock layer of 87 million to 82 million years ago in Kansas, USA (fish and birds were ancient tooth birds living during the White Period).

Torres said: "It has an almost complete skull, which is very rare for this species (fish and bird) and ordinary bird fossils. This new fossil retains most of the bones that constitute the skull, for us Provides the opportunity to observe these bones for the first time.

Therefore, Torres and his colleagues use X -ray computer fault scanning (CT) to digit the facial skeletal and brain structure of fish and birds. Analysis shows that ancient birds like fish and birds have a "old -fashioned" brain; its brain is more like a dinosaur brain, not the brain of living birds.

This picture shows that the shape of the ancestor and fish and birds in the dinosaur era is more similar to the dinosaurs, not similar to the brain of modern birds. Living birds have a unique brain structure, including a big brain. This feature is likely to help their ancestors survive in the extinction. (Source: chris torres)

Torres said that modern birds have a huge front brain compared to their brains. " Today, the front brain of the birds is very large compared to the ancient birds that live in the end of the White Cycles. In view of the fish and birds, a relative that is very close to the living bird still does not have a big front brain like living birds. "We can infer that those big brains have evolved in the ancestors of modern birds." "

Perhaps this large front brain has given the ancestors of the existing birds an evolutionary advantage to help them survive in the "catastrophic global climate change during the great extinction period, which helps to explain why there is only existing [live] Birds, not any other type of dinosaurs, survived, "Torres said again.

However, the brain of fish and birds does have a surprising feature: a raised. This structure was only known in the birds that only lived in after the extinction, and were considered a visual and sensory processing center for flight. It was found in the Birds of the Mesozoic to reveal that the brain of ancient birds was more complicated than before.

The analysis of the brain structure shows that the bird's brain has not evenly evolved over time, but eventually develops into a complex brain structure inlaid. "Jack Zheng, an assistant professor at the University of California, Berkeley Berkeley, Jack Zheng, the Admiral Museum Assistant, said that he did not participate in the study," this is not a clear or more clear linear development that has become more complicated or more adaptable. "In fact, there are some fragmented things that are pushed over time, [with] different combination methods add up."

By: Laura Geggel

FY: Amberly

If there is related content infringement, please contact the author to delete after the work is released

Reprinted, please obtain authorization, and pay attention to maintaining integrity and indicating the source

- END -