The Rise and Fall of Dinosaurs: A 66 Million-Year Journey

Introduction:

Hello, friends! It's been 100 million years since the last time we saw something like this. The land was different. There were no human signs. And some terrifying animals were roaming the entire planet. Dinosaurs. Dinosaurs that were so big that they were taller than buildings. Their jaws were so strong that they could crush your bones in a second. And their speed was so fast that they could run at a speed of almost 90 km per hour. In the right sense, these creatures were heart-touching creatures. They ruled the earth for more than 170 million years.

The Rise and Fall of Dinosaurs:

But then one day, an incident happens that all of a sudden, they disappear from the earth. What exactly happened and how it happened, let's understand in today. As it gets closer to the planet, the earth's gravitational pull gets stronger. They now can't see what's headed that way. The word Dinosaur was actually originated from Greek. It is made up of Dinos and Saurus. Dinos means terrible, Saurus means lizard. A terrible lizard. Literally, this is what the word Dinosaur means. It was first used only in 1841. Because it was the time when a dinosaur fossil was discovered for the first time. A British scientist named Richard Owen started using the word Dinosaur.

Early Dinosaur Depictions:

And at that time, people were not aware of what dinosaurs were and how they looked. So the drawings that were made in the beginning of how dinosaurs would look, they looked quite different from today's comparison. Megalosaurus was one of the first fossils of dinosaurs to be found. Look at its first drawings. After a few decades, as researchers got to know more about it, they modified their drawings. They tried to make it more realistic and the depictions of today are something like this. Today, more than 10,000 dinosaur fossils have been excavated by paleontologists around the world.

Dinosaur Diversity and Evolution:

In which we have identified 900 different species of dinosaurs. You might think that how many more things can we dig to find new things. But the interesting thing is that from 2003 to 2022, on average, every year, 45 new species of dinosaurs are found every year. The work of the paleontologists is not yet over.

The Ancient Earth and the First Dinosaurs:

Scientists estimate that the first dinosaur must have emerged around 230-240 million years ago. Because the oldest fossil of a dinosaur is 231.4 million years old. It was found in Africa. The condition of the earth at that time was very different from the one we have today. The continents you see today, Asia, Africa, Australia, Europe, at that time, all these continents were connected. There was only one supercontinent. Which we have named Pangaea.

The Triassic Period:

Scientists believe that Pangaea looked like this. In this, the different continents of today, where were they exactly, you can see that too. At that time, the climate of the earth was very dry, dry and arid and there was very little rain. We have named this time period as Triassic Period. A time when dinosaurs started to emerge. Dinosaurs started to come to the Earth slowly through evolution.

Early Dinosaurs and the Transition:

The dinosaurs that came at this time were not the way you imagine them to be. In fact, they were very small in size. The most common dinosaurs at this time were usually only 2 dinosaurs you imagine. In fact, they were very small in size. The most common dinosaurs at this time, were usually only 2 meters in size. For example, Eoraptor. It's a dinosaur that existed at this time. And in fact, this dinosaur is also known as the ancestor of all the other dinosaurs.

The Jurassic Period and the Rise of Giants:

But then the climate of the earth started to change slowly. About 201 million years ago, the Triassic period ended. When suddenly the climate of the earth changed. This pangea started to break into pieces. When I am using the word suddenly here, it doesn't mean it happened in a day. I'm using the word suddenly relatively. If we're looking at the time scale of millions of years, it happened gradually in a few thousand years. Cracks started to appear in this supercontinent. There were big volcanic explosions in these cracks. A lot of volcano eruptions.

The Cretaceous Period and Dominance of Dinosaurs:

Because of which a lot of carbon dioxide was released. Sulphur dioxide was released. Due to this, there was a very intense global warming. Then the sulphur dioxide and aerosols that were found in the atmosphere, the sunlight was blocked and after that, it cooled down. Oceans were acidified when the carbon and sulphur dioxide were found in the water. The acidity of the water in the sea increased. What happened was that the climate changed very quickly. And it became difficult for the animals that existed at that time to survive.

The Asteroid Impact and the End of Dinosaurs:

Most of the reptiles and other species were cold-blooded animals at that time. So they could not tolerate temperature changes. But the dinosaurs were warm-blooded like humans. It was easy for the dinosaurs to tolerate temperature changes. For about 6 lakh years, these volcanic eruptions continued. Climate change continued. Because of which almost all the other species became extinct. And the only ones left on earth were dinosaurs, crocodiles, turtles and early mammals. This event is called Triassic Jurassic Extinction Event. And as I said, after this, the Triassic Period ends and the Jurassic Period starts.

The Impact's Aftermath:

If you've heard this name before, then yes, friends, this is the same name. The name used by the Jurassic Park movies, they took the word Jurassic from this Jurassic Period. So this Jurassic Period goes from 201 million years ago and 145 million years ago. At this time, dinosaurs are the most dominant species on Earth.

The Cretaceous Explosion of Diversity:

But due to evolution, some of them have grown in size. Like some of the earliest Titanosaurus, which were alive 160 million years ago, each weighed 15,000 kilos. And could be up to 15 meters in length. Some other iconic dinosaurs that were alive at that time were Brontosaurus, Brachiosaurus, Diplodocus, and Stegosaurus.

Mass Extinction Event and the Impact:

In this Jurassic period, flying dinosaurs also made an entry. The first feathered dinosaur was Archaeopteryx. Which looked something like this. At the same time, our Pangaea supercontinent was divided into two parts. Two small supercontinents. Which we have named Laurasia and Gondwana Land. Because of Jurassic Park's films, Jurassic period is known the most. But in true sense, the next period that followed was the period where the dinosaurs had good days. The Cretaceous period. Because this was the time when we saw an explosion in the diversity of dinosaurs.

The End of the Cretaceous and the Present:

Many new types of dinosaurs started coming here. T-Rex, which is probably the most famous dinosaur shown in movies, actually existed in the Cretaceous period. It reached its dominance at the end of the Cretaceous period. From 65 million years ago to 68 million years ago. Although, there is a discussion among researchers. But most of the scientists believe that T-Rex didn't exist in the Jurassic period. It is very ironic that a film called Jurassic Park is made and T-Rex is shown on its logo.

The Asteroid Impact:

The Cretaceous period was the longest period in the era of dinosaurs. It starts 145 million years ago and continues till 65 million years. The two supercontinents, Laurasia and Gondwana Land, also start breaking up. And the structure of the continents starts looking like today. Many flowering plants are also grown at this time. The temperature of the earth is also very hot in comparison to the previous periods. Sea levels are high. And almost all kinds of dinosaurs that you can imagine, exist at this time.

The Impact's Catastrophic Effects:

But then one km in size, flies towards the Earth at a high speed and collides with it. This happens around 66 million years ago. And this asteroid strike also ends the Cretaceous period. The speed of this asteroid was 30 km per second. That is 150 times faster than a jet airliner. Specifically, it hits the Yucatan Peninsula in Mexico.

The Aftermath of the Impact:

This is the place where the Mayan tribes come after millions of years. And make historical wonders like Chichen Itza. The asteroid had destroyed many carbonate rocks. Because of which, carbon and sulphur go back into the atmosphere. And for the next thousands of years, the sunlight remains quite reduced. It is not in the normal amount. Apart from this, acid rain is constantly present for thousands of years. When the nuclear winter ends, the dust in the atmosphere settles down. Sunlight starts coming back to the planet.

Impact on Modern Biodiversity:

But the problem is that a lot of carbon dioxide has been released in the atmosphere. Because of this, we get to see intense global warming. So, think about it, friends. One asteroid has changed the history of the earth for the next thousands of years. If we ignore some exceptions, then even one four-legged creature, which weighed more than 25 kilograms, could not survive this event. All the terrestrial dinosaurs went extinct. And along with them, all the plants and animal species that lived on the earth became more than 75% extinct.

At this point, the end of the Cretaceous period and the beginning of the next era, which we call the Paleogene period. Now it is not that everything is over, this event is like an opportunity for the remaining animals. The king of the earth, the dinosaurs, are gone. So for the other animals, this is an opportunity to rise and rule the earth. Humans should thank this asteroid first because the mammals got a good chance to evolve after the dinosaurs left. The gap left by the dinosaurs in the food chain was filled in by many mammals.

The Rise of Mammals and Human Impact:

In this period, we saw the evolution of horses, whales, bats, primates, many snakes and small lizards also started emerging here. The only group of dinosaurs that survived were actually flying dinosaurs. They evolved slowly and after evolution, they became birds. You heard it right. The birds you see in the sky today, those flying dinosaurs are their ancestors. Most studies have confirmed that birds belong to the same family as dinosaurs.

Human Impact and Conservation:

The current rate of extinction of species is 100-1000 times more than the normal rate. The habitats of the animals that exist today are being destroyed. Many thousands of mammals, birds, reptiles and amphibians have come under the endangered category today. Or have already become extinct because of humans. To stop this destruction, the United Nations Convention on Biological Diversity meeting was held in Japan in 2010. 20 targets of biodiversity were set to be achieved by 2020. Unfortunately, only 6 of them have been partially achieved. In January 2020, a new Paris-style plan was made to stop the biodiversity and ecosystem collapse. Its deadline was set for 2030. Its purpose is to give the earth's land and oceans a 30% protection. To reduce the pollution that is being spread by us by at least 50%.

The Future and Conclusion:

And the scientists have proposed to keep the extinctions that, keep them at least 20 extinctions per year. The coming time will tell us how many targets are being met. But one thing is for sure, it will be very important to do this. Because if the species of plants and animals are extinct today, in the same way as they were in the previous extinction events, then it may not be possible for humans to survive. And if we talk about humans, their origin was only 3 lakh years ago. In Africa, it is calculated. And if you compare it with dinosaurs, which were dominant on the earth for 174 million years. We are alive for 3 lakh years, but they lived for 174 million years. 600 times more than humans.