What did it go through the most swimming in birds?

Text ｜ "China Science News" reporter Hu Yanqi intern Teng Wenyu

The ancestors of land vertebrates boarded the land from the ocean, and the ancestors of the birds flew from the land to the blue sky.

As a bird, Penguin abandoned the blue sky about 60 million years ago, and once again adapted to the marine ecosystem. It became the strongest dive in birds and successfully survived in the most extreme environment on the earth.

The Chinese and foreign joint teams led by scientists in my country have rebuilt the origin and evolution of penguins through multi -disciplinary joint methods, and revealed the impact of environmental changes, climate and geological incidents on penguin species. How the penguin adapts to the marine ecological environment.

On July 19, related research results were published in "Nature -Communication".

Imperial Penguin, who lives in the Antarctic continent

Multi -disciplinary joint puzzle solution

For a long time in the past, the evolutionary history of the penguin family was confusing.

Scientists are confused between the relationship between the six major tribes of Penguins and have never been able to fully clarify the relationship between penguin species.

There are 32 penguin fossils that have known, which increases the difficulty of streaming of penguin evolution.

Can't understand the evolutionary relationship inside the penguin, you can't understand how penguins have gradually evolved in the form and characteristics of the present, nor can it be accurately understood how penguins evolved under the shape of the polar environment, and it is impossible to answer why the bird ancestors of Penguin are to the ocean to the ocean. Perform secondary adaptation.

In this study, for the first time, scientists collected data such as almost all 74 penguins, including fossil species, and built all 24 kinds of existing penguins and the high quality of the 3 existing penguins and modern extinct penguins in modern times. Genome data set.

"This is the first time the high -quality genome of all modern penguin species is disclosed worldwide, including sub -species, local branches, and recent extinction of penguin species." According to the doctors of the Central Dr. Teresa Cole, "This study also combines genomics and pale biology, which combines comparative analysis of extinction species and existing groups, clarified the evolutionary relationship between penguin members, and also evolved for evolution. Genome research provides many new methods. "

Rebuilding Penguin Family evolutionary process

About 65 million years ago, shortly after the Baiji Biostatic Extinction, Penguin's ancestors appeared in ancient Zealand.

At that time, Gu Zeng was lonely outside the mainland, and the distribution of continents in the southern hemisphere was also close to today. Only the Antarctic continent still connected to the South American continent through land bridges.

The ancient penguin spread from the ancient land to the vicinity of the ancient Luqiao.

40 million years ago, the land bridges connected to the two continents of Antarctica and South America were disconnected. The remaining part of the land bridge became today's Antarctic Peninsula.

Since then, Antarctica is completely surrounded by the ocean. With the gradual opening of the strait, the ocean currents surrounding Antarctic began to form, and the climate of the Antarctic continent became colder.

34 million years ago, the Antarctic ice sheet was formed. During a long historical period, penguins are mainly distributed in the coast of ancient Zealand, Antarctic Peninsula and southern South America.

Many giant penguin species appeared during this period, such as the Ka Crown Penguin, about 2 meters high, the largest penguin known to date.

Until about 14 million years ago, the ancestors of modern penguins appeared in ancient South America.

They spread to Antarctica and first differentiated to form a king penguin. After that, other modern penguin branches also appeared.

"The common ancestor of the present penguin appeared about 14 million years ago, and the changes in the climate environment later promoted the rapid differentiation of penguin species, accompanied by complex gene flow during the differentiation process. It has caused a huge impact. "Zhang Guojie, a professor of the Life Evolutionary Research Center of Zhejiang University, told the Journal of Science of China.

About 2.6 million years ago, the climate of the earth has changed drastically. With the arrival of the Fourth Ji Ice period, a rapid evolution of the penguin family also differentiated most of the biological species in a short period of time.

Their distribution scope is greatly expanded, covering the southern coast of the southern parts of the major continents of Antarctica and other major continents in the southern hemisphere, which basically laid the species pattern today. Penguins have become the most important seabirds in the South Ocean Ocean.

In this process, the gradually enhanced Antarctic Ringji flow is likely to provide important assistance for the spread of penguins.

"In the past 60 million years, penguins have experienced huge environmental changes, especially from the change from warm submarine to 'Bing Hell', but after each environmental change, the penguin branch can stand out, prosper and prosperous, prosperity and prosperity . This reminds Penguin to have strong evolution adaptability to make us optimistic about the future of these magical animals. "Zhang Dexing, a researcher at the Institute of Animal Research of the Chinese Academy of Sciences, told the Journal of Science.

How to shape penguins

Observing penguins from the scale of evolution, and the research team found that their body shape gradually tends to be small; the morphological characteristics such as beaks and limbs are gradually transformed into a more suitable marine environment. Due to the impact of the ice period, the number of penguins species is also the opposite of temperature. The trend of change.

"Traditionally believes that tropical or temperate organisms will have a faster evolution rate relative to polar creatures." Dr. Zhou Chengran, one of the first authors of the paper and the Shenzhen Huada Life Sciences Research Institute, mentioned, "But we found that the high penguins are high as high as heights of high heights. Morneity penguins have a faster evolution rate than low latitudes. This means that the pressure caused by the Antarctic environment and historical climate fluctuations to promote the diffusion and differentiation of the penguin, and to a certain extent, it also promotes the high latitudes of the polar environment to the polar environment to a certain extent. Adaptation. "In addition, the research team also found a series of key genes, summarizing the" genetic tips "of penguins adapting to cold environment and underwater life.

For example, underwater visual ability. Compared with air, the light transmission of seawater is much worse. Due to the absorption of seawater, the light is quickly weakened, and only a little short waves such as blue light can reach the depth of about 200 meters underwater.

"Underwater vision has always been a huge challenge facing the lady. In the penguins, some genetic -sensitive genes have mutated, affecting the light transmission path, promoting the identification of blue light and ultraviolet light, so that penguins have underwater underwater underwater underwater underwater underwater underwater And the keen vision in the dark light environment. "Fang Miao Quan, one of the first authors of the paper and the biological information analyst of the Shenzhen Huada Life Sciences Research Institute, said that it is by the way of changing multiple visual genes that penguins have obtained better underwater underwater underwater underwater underwater vision.

For another example, as a bird with the strongest dive ability, penguin's hemoglobin and myoglobin have a conservative site that is significantly different from other birds. Wang Penguin also has conservative sites that are different from other penguins.

"These characteristics make penguins more efficiently use the oxygen in the blood to make it itself a 'high -efficiency oxygen -rich cabin', which extends the diving time." Fang Miaquan said.

Related thesis information:

https://doi.org/10.1038/s41467-022-31508-9

"China Science News" (2022-07-20 The first edition of the first edition of the original title "Why does it abandon the sky and choose the sea?")

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Edit | Zhao Lu

Capture | Guo Gang

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