Why can't penguins fly?Everything may originate from that dive into the water

Author:Look at the think tank Time:2022.07.26

"Meng Meng Da" penguins are wearing a "gentleman dress". Although they are full of feathers and have a pair of wings, they will not fly. They can only jump from the water and return to the brief on the ice. Experience the feeling of "flying" in time.

Why can't penguins fly? All this may stem from the dive of the penguin ancestors ...

Text | EVEE

This article is reproduced from the WeChat public account "Science Courtyard" (ID: Kexuedayuan). The original first published on July 25, 2022. The original title was "I gave up the blue sky to become the king of water! ", Does not mean looking at the view of the think tank.

It was watering the water to eat

When we thought of birds, the creatures flashed in our minds was the creatures soaring in the sky with wings. Although some scientists believe that all existing birds have the ability to fly recently, many species have lost this ability during the evolution of evolution, such as ostrich, 鸸鹋, and today's protagonist, Penguin.

For the ancestors of penguins, the sky and the ocean are a two -choice question. Of course, everyone knows their answers, that is the vast sea.

According to a research published in the journal "Science" in 2014, scientists have found that the nearest relationship with the penguin in the bird's "family genealogy" is the birds of the process. , Flying on the vast ocean, eating marine life such as fish.

Everyone may not be familiar with this purpose, but some species under this purpose, such as believer and Haiyan, must be no stranger to everyone.

Bird evolution of the whole genome sequence, picture source: reference literature

After the scientists conducted a whole genome sequencing and comparative analysis of 48 types of birds, the scientists built the bird system of the bird system. As a result, the penguins and their close relatives had different differences about 66 million years ago. Since then, the two groups of birds have embarked on a completely different path, one type of wings flying in the sky, and the other type of swimming in the sea.

66 million years ago, in the late Baiji period, the asteroid impact caused a major biostatic incident on the earth. Dinosaurs became history, and the surviving creatures gained a very vast living space. This includes the ancestors of birds, and most of the bird species quickly appeared after this incident, showing a trend of explosive growth.

For the ancestors of penguins, meteorites have destroyed many predators in the ocean. Living in the ocean is no longer a terrible issue without large marine animals. In addition, in the ocean that lacks other large predators, food can be said to be available at hand. Long -distance trekking only for a bite of food has become a past, and a carnival starts.

When the ancestors of Penguin entered underwater life, they started a evolutionary rush. In order to adapt to the marine environment, penguins' bones have become dense and not inflated, so that they can sneak into deeper waters and get food; at the same time, their wings no longer have the ability to fly, but have evolved into fin limbs to help them in the water in the water "fly". There is a way to "have no giant beasts in the sea, penguins are called kings". After adapting to underwater life, with the process of evolution, penguins swim faster, dive deeper, and quickly occupy many areas of the southern hemisphere.

Because they no longer need to fly, they use extra energy to "grow up." The largest penguin existing penguin is emperor penguin, which can grow to more than 1 meter height and weigh more than 40 kilograms. However, compared with some of the close relatives they have already extinct, such a small witch has seen a big witch.

Based on fossil records. Palaeeudyptes, an extinct penguin, can be more than 2 meters tall and weighs 115 kg. Not only that, another Anthropornis, an extinct giant penguin, also has a large head with a height of more than 1.8 meters.

However, with the emergence of other large marine animals such as whale and seals, the dispute in the ocean has resurrected. Some scientists believe that the rise of these competitors may be the cause of giant penguin extinction, but the exact situation needs more research.

Everyone may ask, why don't penguins keep a certain flying ability? In this way, their lives can be easier, and the difficult "marching" on weekdays is only a few hours of voyage. If they can fly, it will be easier to avoid predators such as seals.

Will it fly and swim? That is really not good

In fact, there are seabirds that can fly in nature and dive, and they may hide the mystery of penguins to abandon the flight ability.

Under normal circumstances, there are two driving methods in the water in the water, pushing by wings and pushing the foot. The method of the penguin in the water is the former. The role. Scientists speculate that penguins' ancestors should also be a seabird that can fly and dive, and they rely on the thrust activity of wings in the water.

Therefore, comparing the energy use of different birds during the water, it may bring us the explanation of the above issues. After confirming the research direction, scientists have found two kinds of seabirds for subsequent research. They are Uria Lomvia and Phalacrocorax PELAGICUS. The latter depends on the thrust generated by the foot to swim in the sea. Scientists believe that the two birds can be used as the biological model of energy use during the sky and ocean in the sky and the ocean. By understanding their energy consumption during flight and diving, the penguin ancestors have given up their flying ability.

Researchers captured some mouth crows and sea crickets, and injected them stable hydrogen and oxygen isotope as tracer to mark their energy consumption. At the same time, scientists also equipped seabirds with sports. Equipment to record their sports data. The results show that the life of the seabirds is mainly composed of flight, diving and rest. Researchers calculate the energy costs that each activity requires, and draws interesting conclusions.

According to the measured data, the flight cost of the thick mouth crow is the highest among flying birds. When they are flying, they consume more energy than other birds at all times. In other words Tired. But at the same time, the cost of moving in the water in the water is relatively low, which is much better than most birds.

In other words, the advantage of the energy consumption of thick -mouth crows in water is exchanged for large flight costs. But even so, after the weight conversion, the energy consumption of the same -sized thick mouth crow dives is greater than the penguin.

In this regard, scientists speculate that when wings are used in air and water, there may be a critical point of energy use. After exceeding this critical point, the flight cost of sea birds will become high. In order to obtain greater advantages in the water, some birds, such as the ancestors of penguins, chose to completely give up the ability to fly, and turned to live in the sea, becoming a swimming master.

According to observations, the swimming speed of Emperor Penguin can reach 14.4 km/h; when the Adeley Penguin small universe erupts, the swimming speed can even reach 30 to 40 km/h. In addition to swimming fast, penguins are still dive, and Papua Penguin's maximum diving depth can reach 200 m; the deepest diving record of Emperor Penguin is 565 meters, which can stay in the water for nearly half an hour.

As the saying goes, "fish and bear's paw, the two are not available for both", the same is true for penguins. If you want to be a swimming master, you must pay something.

The evolution of penguin wings may be the result of energy consumption.

More changes, let the penguins proof to the ocean

Of course, penguins can have today's success, not only because of the abandonment of the ability to fly. There are many secondary aquatic adaptation mechanisms on penguins.

The dense bones help them overcome the buoyancy of the seawater like the compression of the warehouse, and help them sneak into the deeper sea;

Densely waterproof feathers, thick skin, and subcutaneous fat can help them regulate their body temperature in the cold environment and water;

The glands near the eyes are the gonads, which can help the penguin excrement from excess salt in the body;

Eyes can quickly adapt to the rapidly weakening light environment of the deep sea, allowing them to move better in the water ...

In a recent research papers published in the journal "Nature · Communication", scientists have found a series of genes that may help penguins adapting to water in water through comparative genetic analysis, including the evolution of fins, body temperature, body temperature Gene -related genes related to vision.

The various aquatic adaptation mechanisms of penguins, pictures source: reference

The discovery of all -gene sequencing and these functional genes undoubtedly helps us go further in the study of penguin adapting to the aquatic environment. With the changes in the environment and the increasing atrophy of the habitat, the future of many penguins has become the same as the Antarctic continent. It is facing great uncertainty. I hope that these research on penguins will promote human cognition of human beings. It can also promote the protection of penguins.

Reference materials:

[1] Elliott, K. H., Ricklefs, R. E., Gaston, A. J., Hatch, S. A., Speakman, J. R., Davoren, G. K. (2013). High flight costs, but low dive costs, in auks support the biomechanical hypothesis for flightlessness in penguins. Proceedings of the National Academy of Sciences, 110 (23), 9380-9384.

[2] jarvis, e. d., mirarab, s., aberer, A. J., li, B., HOUDE, P., li, c., g. (2014). Whole-Genome Analyse Early Branches in: Taxonomic and Evolutionary Remarks. Geobios, 47 (3), 77-85.

[4] Genomic Insights Into the Secondary Aquative Transition of Penguins