2023-04-25 09:13:37
What is the meaning of paleontology? Take a peek at a species that breaks the rules!
I’m often asked “why study paleontology at all?” and I usually pick up bits and pieces regarding the origin and evolution of life, as well as a broader cultural understanding of the history of life and the Earth’s environment.
A key reason, however, is that some ancient creatures broke all the rules.
Elephants’ size is the limit for any land animal, and adding too much flesh might overwhelm them or starve them to death in a changing climate, biologists say.
However, dinosaurs, especially the group of sauropods, are an excellent example of how the impossible can come true—we can’t say that gravity was lower in the Jurassic, or that they lived forever. Stay in the water (although some lunatics really make these claims).
So, how on earth do we explain the existence of these incredibly large sauropods?
This Martin. Sander’s original questions have been answered with the joint efforts of many paleontologists today.
He had an amazing idea, and he raised five million euros for a long-term research project from 2004 to 2015, which is probably every schoolchild’s dream project – His project is called “Biology of the sauropod dinosaurs: the evolution of gigantism.”
Sander recruited more than two dozen researchers, not only paleontologists but also nutrition experts, botanists and zookeepers. He wanted to solve once and for all what made saurischian dinosaurs so massive.
Paleontologists eyeing the biggest dinosaur ever: the tall-breasted brachiosaurus
His mind had long been on the biggest dinosaur, the Brachiosaurus (below), in the Late Jurassic formations of Tanzania, East Africa, and the American Midwest. Its skeleton is quite astonishing, 26 meters long, which is equivalent to two ordinary carriages measured from head to tail. Its head rises from the ground and is 9 meters high, which is equivalent to the height of a 3-story building.
Unlike other sauropods, Brachiosaurus had extra-long front legs that elevated the front half of its body, a bit like a giraffe. The vertebrae in the neck showed that the natural position of the neck was at an angle of regarding 45 degrees. Unlike other saurischian dinosaurs, such as Diplodocus and Camarasaurus, their necks were kept horizontal.
So Sander’s research focuses on figuring out how these 40- to 50-ton behemoths work.
If the elephant’s food intake is used to estimate, how much did the dinosaur need to eat?
In 2011, I went to Bonn to participate in one of the international federations, and I was very interested in the reports. One of them was a human physiology experiment. A group of American professors recruited students to carry out a series of strange diet plans. Say one who ate only hamburgers or lettuce for a month (such experiments would probably not be permitted today), and one who was a zookeeper who measured the feeding and excretion of elephants and other beasts.
Zookeepers report that elephants must eat up to 270 kilograms of forage per day.
As Sander points out, if sauropods had had the same physiology as modern elephants, they would have required 10 times as much food, or 2.7 metric tons.
It was a pile of leaves as big as a passenger car. What’s more, zoo keepers noticed that their elephants turned this 270kg of plant food into 70kg of dung every day—that’s enough to fill dozens of wheelbarrows.
Sander wondered what plants the Mesozoic sauropods ate, and how sauropod physiology differed from that of elephants. Of course, their bone histology already shows that they were warm-blooded animals, but the size of these dinosaurs is huge, regarding 50 tons, and if they eat at the same rate as elephants, the food intake may not be enough to fill them Extra long neck.
Crack the secret of dinosaurs “growing bigger but eating less”!
So he pulls together what we know regarding dinosaurs, and sauropods in particular, and draws out an overview of the secrets to understanding their growth—a picture that shows exactly how sauropods, the largest animals that ever lived, got there. This impossible task.
This is achieved through a combination of many offspring, small eggs, no parental care; small heads, no chewing, and bird-like lungs—which are more efficient at absorbing oxygen than reptiles and mammals. These traits allowed sauropods to grow to gigantic sizes with minimal food intake—perhaps eating as much as an elephant, or even less, while being ten times larger.
They use their large bodies to stabilize their body temperature, rather than eating a lot and having a complex internal heating system like elephants and humans do. They lay small eggs and walk away, unlike elephants and humans who devote a lot of time and energy to caring for a baby or two, depleting the mother’s food reserves.
Sander’s network diagram explains all this very convincingly-it is the reason why sauropods can escape the size constraints of elephants and mammals.
In addition to large dinosaurs, there are also “dwarf” dinosaurs
Since they all reached such a huge body shape, why did the dinosaurs become smaller later?
The maniraptor branch of the theropods became smaller and grew longer arms for arboreal and eventually flight (see Chapters 4 and 1 of Who Feathered Dinosaurs? Chapter Eight). Their new lifestyle of hopping up and down trees might explain why dinosaurs shifted to smaller sizes.
All over the place, there are some dinosaurs that got smaller because they lived on islands. The most famous are the pygmy dinosaurs of Transylvania – a place whose name sounds like something out of a movie, but has a place in real life.
These dwarf dinosaurs did indeed live in this corner of what the Romanians used to call Transylvania, and they were originally discovered by Franz. Described by Baron Franz Nopcsa, he was a down-and-out aristocrat in the Austro-Hungarian Empire at the time (at the end of the nineteenth century).
I first went to Romania for research in 1993, four years following the country had overthrown its pro-Soviet government by force — and I saw bullet holes in some buildings at the University of Bucharest.
Discovery Channel wanted to do a show regarding Nopsa, mainly because he had a very rich life—he was not only an aristocrat, but also a gay man with his loyal secretary and lover Bahazid. Up to (Bajazid Doda) toured Europe together.
Nopsa speaks multiple languages and speaks regarding his dinosaur research at seminars in England, France and Germany, but has to sell his fossil collection to make ends meet.
He served as a double agent during World War I, between Austria-Hungary and Great Britain, worked with partisans in Albania, and volunteered as Albania’s king. Finally, in poverty and desperation, he shot Dodo and himself in 1933.
This kind of life is more than enough for a thirty-minute film, but I still insist that we need to add some science, and the dwarf dinosaurs do have important biological significance.
Nopsa was the first to mention that Transylvanian dinosaurs were dwarfs, at a conference in Vienna in 1912. He observed that Transylvanian dinosaurs rarely exceeded four meters in length, and the largest sauroschian dinosaur was later named Magyarsaurus (Magyarosaurus dacus), are only six meters long, but their relatives elsewhere are fifteen to twenty meters long.
Finding out why dinosaurs ‘dwarfed’
In the discussion following the publication of the paper, the outstanding Austrian paleontologist Ortenio. Othenio Abel agreed with him, saying the phenomenon is similar to the dwarfing of elephants, hippos and deer that lived on Mediterranean islands during the Ice Age.
In this way, Nopsa and Abel settled the matter. There are many evolutionary arguments to explain this phenomenon, but it is clear that the main reason is that islands can support fewer species and are much more streamlined than continental ecosystems.
So as species numbers, food, and ranges decrease, animals develop size, diets, and habits for these environments, so large animals have to get smaller.
In the last million years, pygmy elephants on Mediterranean islands such as Malta, Sicily, and Sardinia had a shoulder height of only fifty centimeters to one meter, while today’s adult elephants can reach a shoulder height of four to five. meter.
Apparently, elephants, hippos, and other African mammals must have crossed to these islands when sea levels in the Mediterranean were much lower than they are today, because the sea was still frozen in the great northern ice cap.
The dwarfed dinosaurs of Transylvania lived on the island of Haţeg, which was between 100 and 200 kilometers long and was one of several large islands in the Late Cretaceous, when the sea level was very low. high and flooded much of southern Europe.
once morest the sauropod Magyarsaurus (Magyarosaurus) and the ornithopod swamp dragon (Telmatosaurus) and Chamosis Dragon (Zalmoxes) histological study of the bones of these three dwarfized dinosaurs and found that they were all adults, not juveniles. But they are only one-third to one-half the length of their relatives in Europe and North America.
Not only were they shrunken in size, but somehow they seemed to be more “primitive” dinosaurs, 20 to 30 million years older than their closest relatives on the mainland. Their ancestors are presumed to have settled the coasts, severing links between groups as sea levels rose.
Then, while their continental relatives continued to evolve, island-type dinosaurs continued to live the same lives in less complex ecosystems, perhaps without the same competitive pressures.
So, with the exception of these rare island-type dinosaurs, most dinosaurs evolved to get bigger and bigger. Interestingly, dinosaurs showed the same adaptations as mammals, and they may have been smaller when small body size had an evolutionary advantage.
——This article is excerpted from “Who gave dinosaurs feathers? July 2022,facebook publishing。
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