Birds evolved from land to sea to sky
Throughout the 150 million-year evolution of birds, different populations of birds have played a variety of different roles... The species diversity of Earth's birds is stunning.
If we were to remember birds as just the chirping birds that often appear in our backyards, such as sparrows, birds of the birding family, and goldfinch, we would never have been able to imagine the astonishing diversity of birds. Although these birds, which we often see, form a beautiful landscape in our backyard, they have played only a small role in the 150 million years of evolutionary history of birds.
Throughout the evolution of birds, different populations of birds play different roles, some of them change the ecological landscape of the landing, some are dive masters in the ocean, some are hunters who prey at night, and some even become predators at the top of the land food chain. Many unusual bird species have gone extinct, and others have evolved into bird forms we see today. In places rich in rock sediments such as China, Wyoming and Peru, many bird fossils have been newly discovered in recent years.
It provides us with new clues to the evolution of birds. Since 2000, more than 300 newly discovered species of birds have been named, filling in the gaps in the evolutionary history of birds and enriching the map of bird diversity.
Ancient birds soaring through the sky
The earliest known bird is called Archaeopteryx,
They lived during the Jurassic period 150 million years ago. At that time, the land was the world of dinosaurs, armored stegosaurs, huge giraffes, etc., leisurely strolling on the earth full of lush plants (such as pine, ginkgo and cycads), but the sky at that time was not dominated by Archaeopteryx, they ruled the sky in ancient times together with flying reptiles known as pterosaurs.
During the Jurassic Period, earth's paleocidates began to split, and Africa, South America, Australia, and Antarctica remained contiguous, known as the Gondwana supercontinent, and much of Europe was submerged under shallow seas. The 11 Archaeopteryx skeletons that have been found were found somewhere in present-day Germany, where the bottom of the lagoon is the last resting place for these ancient birds.
Over the next 84 million years, a large number of primitive birds lived on Earth with their dinosaur relatives, and these birds gradually evolved teeth, claws and long bony tails. By 66 million years ago, an asteroid impact triggered a mass extinction event that wiped out all dinosaurs on the ground, pterosaurs in the sky, marine reptiles like plesiosaurs in the oceans, and many other species. Some birds survived, but many species, including those with toothed animals, went extinct.
After this mass extinction, birds began to rise, and more than 1,000 "modern" birds began to take the stage of history. The surviving birds that emerged after the extinction cataclysm began to expand around the world, filling and adapting to the vast ecological space left by extinct species. Following the Cretaceous-Tertiary extinction following this period of bird biodiversity, a number of birds that we are familiar with and unfamiliar have emerged, including parrots and ratbirds that live among trees, penguins that inhabit the water, and giant pseudo-toothed birds that soar through the sky and moa birds on land.
Birds during the Eocene
According to fossil records, bird diversity expanded further during the Eocene, which began 56 million years ago. The predominantly climatic feature of the Eocene period was global warmth and ice-free, with temperate and subtropical forests expanding and extending outward in most parts of the world. In some fossil-rich sediment layers at the bottom of ancient lakes, such as the Green River Formation in the United States and the Messer Formation in Germany, many precious bird fossils have been discovered for the first time.
Fossil skeletons of birds in the Eocene show that birds began to play more new roles in the history of biological evolution as they evolved more new species. Among the birds found in Eocene lakes, one of the earliest tropical seabirds called the frigate bird either glided on the surface of the water in search of fish or stole prey from other birds; early birds that were able to fly rapidly in the sky while preying on insects; parrots' most primitive ancestors grabbed branches with their special claws and perched on trees; along the muddy coastline, a wader called the crooked ibis searched for invertebrate prey with their slender, curved beak; Nocturnal birds also began to appear during this period with the appearance of their close relatives of the fruit-loving South American monster, the nocturnal insect-eating birds of the forest plover family, and the broad-beaked, bird-eating frog-billed nighthawk.
Most people probably never get the chance to see a small, gregarious bird in their lifetime. As the name suggests, ratbirds like to crawl through plants and sometimes use their dexterous toes to hang upside down on the branches of plants. The six species of ratbirds that live on Earth today all live in sub-Saharan Africa, and those unfamiliar with them may think they will play little role in bird evolution. However, this is not the case.
Fossils show that during the Eocene and Oligocene eras (56 million to 23 million years ago), ratbirds underwent a process of diversified development, and various forms of ratbirds appeared. In this golden age of ratbirds, the ratbird species popular in North America and Europe include: the scientific name Chascacocolius cacicirostris, the sharp-beaked ratbird that likes to peck at bark and hard-shelled fruits, the scientific name Celericolius acriala, which has long wings and likes to look for insects, and the ratbird with the scientific name oligocolius psittacocephalon with a parrot-like head. This class of ratbirds is known for finding many plant seeds in their bones. These rich and diverse species disappeared 25 million years ago, eliminated by more successful songbirds in the natural evolution of natural selection. The ratbird's boom and subsequent disappearance is just one example of the evolutionary development of species from prosperity to decline.
Birds returning to the sea
Since the first evolution of terrestrial vertebrates nearly 400 million years ago, many species have returned to the ocean, leading to the second rise of aquatic species such as whales, seals, turtles and penguins, all of which are well-known examples of this transformation of bird populations from terrestrial to marine life.
Only a few million years after the Cretaceous extinction event, penguins achieved this transformation. In the Paleocene period, there was an ancient penguin called Kairuku grebneffi, which could stand at a height of up to 1.3 meters, 30% higher than the largest penguin living in modern times.
The extinct Plotopterids, a little-known diving bird, followed the penguins into the sea during the Eocene. With the exception of galapagos penguins, almost all penguins are from the southern hemisphere, and from 35 million to 15 million years ago, plotopterids lived on the coasts of Japan and the Pacific Northwest, and although they look very similar to penguins, they are actually more closely related to gannets and cormorants.
The third species of birds to return to the sea is the puffin family, which has gradually adapted to marine diving life since the Late Tertiary period. Like penguins and divers who entered the sea before them, webbed puffins gradually lost their ability to fly during evolution, and by the Miocene and Pliocene, their wings evolved into flippers. The return journey of the large, short-winged, webbed puffins to the sea was not very successful because they did not evolve more powerful wings and scaly feathers like penguins. Unfortunately, the species of this population disappeared entirely in the mid-19th century due to overhunting by humans.
From the Miocene to the Pleistocene, another group of Lucas puffins also began to move into the ocean, evolving shorter, more flipper-like wings. The great auk once roamed along the northern Atlantic Ocean, while the Lucas puffin lived along the Pacific coast.
Modern puffins
The evolution of these four lineages of birds is a classic example of the evolution of species convergence, that is, the evolution of unrelated populations that gradually adapt and form superficially similar structures as a result of being in similar environments. Each population of birds that marched from land to sea solved the problem of underwater movement in the same way: dives with wings that were more adapted to underwater life. The reason why different groups of birds have this phenomenon of convergence and evolution in the process of moving from land to the ocean is that the wings of birds are originally adapted to flying in the air current, and in the process of convergence evolution, they have gradually adapted to "flying" in another fluid, seawater, except that the density of seawater is almost 800 times the density of air.
A giant bird that dominates the land
On Earth today, carnivorous mammals such as lions and wolves play the role of predators at the top of the food chain in most terrestrial ecosystems. However, during the Cenozoic era, a flightless predatory bird became a terrifying nightmare for mammals on land in South America. This ancient bird, known scientifically as Phlusrhacids, is generally called moa.
They are a huge population, and this flightless land bird emerged shortly after the extinction of the terrestrial dinosaurs. In a way, moa represent a reenactment of evolutionary history. Like their Cretaceous dinosaur predecessors, they were a terrifying "killer" with huge heads, bipedal walking, and oviparities—sharp teeth, forearms that replaced wings, and bony tails that resembled miniature versions of Tyrannosaurus rex.
The largest moa skull ever found is 70 centimeters long, and this massive skull belongs to a giant moa called Kelenken guillermoi that lived in the mid-Miocene about 15 million years ago. The moa survived to this day's close relatives are two species of cranes, two carnivorous birds that are only about 90 centimeters tall, but with their sharp claws and beaks, they become the most feared in the eyes of rodents and some small reptiles.
The last miracle of the prehistoric period is the huge prehistoric ancient bird with the scientific name Peliagornithidae ,"
These birds survived until the Pliocene, disappearing about 3 million years ago. Humans only began to appear in Africa about 2.4 million years ago, so our earliest immediate ancestors were also lost to these giant birds soaring in the sky.
With a wingspan of nearly 6 meters, these giant birds were much larger than today's albatrosses and vultures. Fossil skeletons of this giant bird and its close relatives have been found on all seven continents, indicating that these birds are adept at flying long distances, crossing the world's oceans with their ability to glide and fly quickly, and eventually reach all over the world. One of the strange properties of these giant birds is that their jaws are covered with tooth-like bony protrusions, pseudo-teeth. Unlike really glazed teeth, these dentures are really just growths of the skull bones.
The tragedy of Bird Island
Throughout human history, no matter where humans newly migrate to, they pose a huge threat to the survival of endemic birds. The extinction of more than 500 species of birds living on islands around the world is closely linked to human migration activities. For example, new Zealand's moa birds are directly extinct due to human hunting for food, while many birds are wiped out as a result of indirect effects of human activities, such as the introduction of alien food species, the destruction of bird habitats due to the burning of woodlands, and so on.
On the list of vanished birds on many of the world's islands, it includes the largest terrestrial bird that has ever appeared in the history of the earth. For example, a giant bird that lives on the island of Madagascar can reach a height of about 3 meters. For example, many of the dozen or so moa birds that live on the island of New Zealand are huge giant birds. Other rare birds that have disappeared include a flightless, nocturnal, smell-hungry platypus in Hawaii; the dodo and its close relatives; and several species of terrestrial New Zealand wrens that disappeared in 1972.
wren
Although species extinctions are part of natural evolution, some bird extinction events in recent times are not just natural causes. The Cretaceous extinction event, while wiping out some bird populations, also created opportunities for the rise of other bird populations. What we're seeing today is that bird biodiversity is fading away and replaced by homologous invasive species that reduce the natural resilience of island ecosystems.
Some might argue that birds like the dodo are doomed to extinction because they can't fly, move slowly, or can't adapt to their environment. However, this is a dangerous misconception. These species went extinct not because of some of their own flaws, but because the environment changed too quickly to adapt quickly. For example, there was no threat of mammals on the islands, and birds nesting on the ground could hide from aerial predators like eagles, but when land predators such as cats were taken to the island by humans and bred, the ecological environment that was originally beneficial to birds became dangerous.
The same phenomenon occurred in Guam, where the introduction of snakes led to the extinction of all native birds on the island. For example, it is thought that the introduction of the palm tree snake led to the total extinction of the Micronesian kingfisher of Guam in the wild. How to prevent the further extinction of birds in time and avoid the increase in the list of bird species extinction is an urgent need to face up to the problem that needs to be faced, and I hope that the tragedy of Bird Island will not repeat itself.