Dinosaurs and extinction event : Origin and end of prehistoric creatures. Life after the Extinction
Probably no other creatures on the planet have struck as much fear and awe in our hearts as the dinosaurs. The earliest dinosaurs appeared about 245 million years ago during the Triassic Period. When most of the Earth’s landmasses were still joined together as the super continent Pangaea. Over millions of years Pangaea split apart causing the dinosaurs to become separated for the very first time. This led the reptiles to adapt to their specific habitats and diversify. Giving rise to many new dinosaur species.
According to some estimates, more than 1,000 species of dinosaurs have roamed the Earth. All dinosaurs descended from reptiles called Archosaurs. From there dinosaurs branched out into two major groups, Saurischia and Ornithischia based on the shape and orientation of their pelvis. In Saurischian dinosaurs, such as Tyrannosaurus Rex and Brachiosaurus, the pelvis’ pubis bone faces forward and down. In Ornithischian dinosaurs, such as Stegosaurus and Hadrosaurs, the pubis bone faces backward and down. Across both groups, dinosaurs varied greatly in size. Some were small, like Compsognathus, which was barely larger than a chicken. Where as others were gigantic, like Dreadnoughtus, which was 85 feet long and weighed 65 tons, making it the largest land animal to have ever lived. Dinosaur diets varied as well. Herbivores, like Hadrosaurs, evolved to have specialized teeth for grinding tough plant material.
Carnivores made up roughly 40% of dinosaur species. Some predators, like the raptor Deinonychus, even hunted in packs. Social behaviors were also found in other dinosaurs. Footprints and track ways indicate that some of the ancient reptiles traveled together. Evidence also shows that herds may have made annual visits to certain sites to lay their eggs. But by around 66 million years ago, most dinosaurs died out. And the reason why is still a mystery. The most well known explanation is an asteroid strike. But a multitude of factors may have contributed to this extinction. In fact, the dinosaur population was already in severe decline by the time the asteroid struck. However, several dinosaur species survived. And some of which evolved to become today’s birds. The world has never again seen land creatures as great as the dinosaurs. But through their descendants and fossils left behind, their legacy lives on.
Extinction
When the asteroid struck most of the impact energy was deflected out or up only one percent of the force traveled down into the ground. But it’s enough to ring the planet like a bell seismic waves radiate across and through the earth 16 minutes and 40 seconds later they reach the pacific northwest. The valley shakes as a magnitude 11 earthquake ripples through the ground. Larger animals panic at the edges of the valley in their desperate attempt to escape the tremors and falling debris smaller animals take shelter underground meanwhile the ejecta cloud approaches at 16,000 kilometers per hour baking the earth with unrelenting heat millions of volts of static electricity charge the cloud like a giant battery creating a vast electrical storm superheated rocks shower the valley in a burning hail.
Just hours ago north America was a dinosaur paradise now it’s a living hell. The ejecta cloud continues its spread across the globe but the effects it has on the ground vary dramatically. Twelve thousand kilometers away in Mongolia the cloud rolls in silently from the east temperatures on the ground creep upwards a few degrees hotter. Every second there’s no audible warning for the creatures, here only the mounting heat as the air reaches 50 degrees Celsius. Their only hope is shelter at 70 degrees. Survival is measured in minutes and at over 90 degrees in mere seconds. 90 minutes after impact the temperature on the ground in Mongolia peaks at 150 degrees Celsius which ultimately causes the dinosaurs to become extinct as the temperature was to high to handle.
Effects after extinction event, survivors and recovery
About 66 million years ago at the end of the cretaceous period the planet lost its dinosaurs everyone knows that this happened because of a global catastrophe but what happened immediately after the mass extinction ?. At the end of the Mesozoic era a huge asteroid or comet crashed into the earth. Scientists are still arguing about this the diameter of this celestial body was anywhere from 11 to 80 odd kilometers or from 7 to 50 miles, that is on average it might have been the size of the city of Washington DC when one edge of the asteroid had already hit the ground the other end was still higher than the flight zone of the Boeing 747. Such a collision couldn’t pass without a trace. The asteroid left behind a giant crater. It covered half of the gulf of Mexico and no wonder the crater has a diameter of 150 kilometers or 93 miles and a depth of about 20 kilometers or 12 miles. This wasn’t the first collision between our planet and a celestial body but it has become one of the largest the world changed in an instant the impact caused mega tsunamis with a height of more than 100 meters or 330 feet that reached the territory of modern day Texas. In Florida other sources indicate a height of 300 meters or 985 feet, that’s for example the height of the Eiffel tower. And some claim that the first wave rose up to one and a half kilometers or nine tenths of a mile tall five Eiffel towers. The asteroid displaced so much water from the ocean that huge waves crashed on the coastline for 10 hours and this isn’t even the worst case scenario if the impact had been deeper the tsunamis would have been even taller the explosion that occurred when the celestial body fell was about a hundred million times more powerful than the famous thermonuclear tsar Bomba forests within thousands of kilometers or hundreds of miles were destroyed in just a second . Some scientists believe that the explosion was equivalent to a hundred trillion tons of TNT . It was enough to destroy the coastline caused 12 point earthquakes and landslides all the way to Argentina and these in turn caused new tsunamis a real chain of horror impossible to survive. If you found yourself in its path but this was only the beginning of the disaster .
The energy with which the asteroid crashed into the earth was enough to set fire to the landscape within a radius of 1500 kilometers or 930 miles, even huge dinosaurs like diplodocus died those that weren’t hit by the explosion or fire were dragged away by the retreating wave tiny particles of rock and other fragments were thrown high into the atmosphere. Later geologists have found these fragments all over the world because after being blown into the air about 40 minutes later the particles began to fall rapidly. They were like drops of hot glass, their kinetic energy was equivalent to 20 million megatons of TNT and all of it was converted into heat. Each falling particle turned into an incandescent lamp together they quickly warmed up the atmosphere and the earth became a real hell the vast majority of dinosaurs and many other terrestrial organisms were in the affected area after avoiding a tsunami or earthquake they likely died after a few hours from intense heat the planet previously covered with forests almost instantly caught fire about 75% of living things were destroyed including any mammal weighing more than 25 kilograms or 55 pounds.
Acid rain oxidized the oceans half of the plant species also died immediately or within a few hours soot from the fires combined with dust from the impact blocked the sun’s rays the earth was deprived of sunlight for about a year. This greatly affected the climate. In the end some of the plants that managed to survive the impact also died after these large herbivores miraculously survived. Then carnivores water ecosystems were also destroyed but not completely for example turtles and the ancestors of crocodiles managed to survive. Some researchers called the environment of that time lunar desolate and barren as it was it was almost impossible to survive in such conditions yet life on our planet didn’t stop as i said all of the big animals died, those who remained began to repopulate the land . The foraminifera were the first to recover. These are single-celled organisms that appear in the crater a few years after the impact then the ferns awoke in just a millennium. They were able to expand and occupy almost all of the space that was left but large mammals faced different conditions. There wasn’t enough food therefore only small animals weighing no more than 600 grams or one and three tenths of a pound roamed among the ferns. There were just a few flowering plants and nutritious seeds in the world but after a hundred thousand years mammals returned to the size of a raccoon, the ferns were replaced by palm forests, there was more food the world was gradually returning to normal. 200,000 years later the so-called palm period was replaced by the period of pecan pie of course no pies were prepared then but there were not like plants this means that there was much more nutritious food. Mammals took advantage of this. The diversity of species increased by about three times. The largest individuals reached 25 kilograms or 55 pounds this is the weight of a fairly large beaver or gazelle. It seems that mammals evolved along with plants finally about 700,000 years later there were beans and this is much more important than it seems at first glance. Beans worked as protein bars for ancient mammals they further increased the size of the animals and at the same time the diversity of species.
At this stage the future rulers of the planet weighed more than 50 kilograms or 110 pounds. This is about the weight of a large modern cheetah. The ancient mammals were a hundred times heavier than their ancestors who lived among the ferns and less than a million years had passed. Yes for a human or any other creature that’s a very long time, but for evolution it’s nothing. The oceans recovered much more slowly. Scientists estimate that it took them about 3 million years, only then did the flow of organic material return to normal new species took over the vacant ecological niches. Paleontologists consider birds to be one of the few surviving dinosaurs. Their non-avian relatives died out but a small portion of lizards still adapted, most likely their ability to dive swim or seek shelter in water in swamps helped them. Many bird species can build nests on the ground, all of this helped their ancestors cope with the horror that was happening around them, as a result life on earth returned to normal.
Over time evolution led to the appearance of humans. This wouldn’t have happened without the asteroid hitting the earth. We can say it was a trigger for human evolution but what would happen if such a disaster struck again ? well you already have a rough idea, surely most of humanity wouldn’t survive a new attack from space but our planet would certainly recover. Life goes on despite the fact that we’re talking about events that occurred tens of millions of years ago. Today scientists know quite a lot about them this was made possible by fossils as well as various samples of earth and stones for example from the bones of ancient mammals and lizards scientists have learned when the age of dinosaurs ended.
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