Are there still dinosaurs in some parts of the world today? – Ruben M., 5 years old
Did all dinosaurs grow to be extinct when an asteroid hit the Earth 66 million years ago? Or did a few of them in some way survive this mass extinction – and their descendants are still alive today?
It's exciting to think that enormous dinosaurs were still lumbering and plodding about in some distant a part of the world. But there's no evidence of that. There's no relation to tramping through the vast forests of Siberia or strolling through the rainforest of the Congo.
As a paleontologistI've spent much of my life studying ancient animals, especially dinosaurs. But I've only seen fossils of those creatures, nothing living – with one exception. One group of dinosaurs remains to be around. To find them, just go outside and look up.
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The killer asteroid
In 1977 The American geologist Walter Alvarez worked within the Apennines in Italy. There he found a skinny layer of clay with an unusual amount of a metal called iridium in it. The clay was between rocks from the chalk And Paleogene Periods and dates from the time of the disappearance of the dinosaurs.
Iridium is rare on Earth, but more common in some areas Meteorites. The collaboration along with his father Luis, who a Nobel Prize-winning physicistWalter Alvarez developed the idea that an enormous chunk of space – a asteroid – collided with Earth 66 million years ago. This impact left traces of iridium all around the world and triggered the unimaginable catastrophe that killed the dinosaurs and countless other animal and plant species on land and within the sea.
At first, many scientists rejected this theory. But then in 1991, geologists discovered an enormous crater under the ocean floor off the Mexican Yucatán Peninsula. An asteroid about 10 kilometers in diameter had hit this spot. crashed onto our planet 66 million years ago.
The impact was so powerful that trillions of tons of dust and molten rock were thrown into the sky. Many pieces of molten rock fell back to Earth, causing massive forest fires in all places. A thick layer of dust within the atmosphere blocked a lot of the sunlight, resulting in freezing temperatures worldwide. The Earth was a chilly, desolate place. over a few years, even centuries.
The lack of sunlight caused many plants to die. Since there was no food for them, large herbivorous dinosaurs just like the Ornithologist quickly died out. Large predators just like the Ornithologist subsequently had no prey and died as well.
But smaller animals like Mammals, lizards and turtles were capable of adapt. They could hide in caves and survive a wide selection of food. Fish lived in rivers and lakes and were protected by their watery habitats. And with them survived: birds, the one remaining dinosaurs.
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The bird connection
Fast forward about 66 million years: In the nineteenth century, scientists noticed how the skeletons of today’s birds and fossilized dinosaurs were similar in some waysThe similarities were particularly striking within the legs and feet. However, most scientists on the time believed that dinosaurs and birds were too different to be closely related.
Then, in 1964, Dinosaur expert John Ostrom discovered fossils of the dinosaur. It had a mouth stuffed with sharp teeth with serrated edges like steak knives, long slender hands with three fingers ending in large, curved claws, and an enormous claw on the second toe of every foot. A quick hunter that didn’t fit traditional ideas of dinosaurs as slow and never very energetic, it lived in North America in the course of the Cretaceous period about 110 million years ago.
For one other research project within the early Nineteen Seventies, Ostrom studied the oldest known bird, that lived in what’s now Germany 150 million years ago. It had feathered wings and a wishbone, in addition to reptilian features, including jaws with sharp teeth, hands with three fingers each, and an extended tail.
Comparing this ancient bird with , Ostrom found that their skeletons shared many unique features, including unusually long arms and hands, a highly flexible wrist, hole bones, and an S-shaped neck.
Based on these and plenty of other similarities, Ostrom showed that birds descended from small, predatory, bird-like dinosaurs.
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Over the past three many years, paleontologists have discovered many skeletons of prehistoric birds and bird-like dinosaurs in Jurassic and Cretaceous rocks in China. Surprisingly, the bird-like dinosaurs, including close relatives of prehistoric dinosaurs, were covered in feathers, identical to the birds that lived with them. Paleontologists now agree that many, if not all, dinosaurs had a consistently high body temperature, identical to birds and mammals today. Feathers kept them warm.
Bird-like dinosaurs didn’t survive the mass extinction 66 million years ago – a number of the early birds that lived alongside them survived. And they evolved into the birds that live today.
Think about it: To see a dinosaur, all you may have to do is look up on the sky. And since I've been studying dinosaurs for a very long time, I'm glad I share the world with dinosaurs.
image credit : theconversation.com