The rise and fall of dinosaurs is a game of chance, scientists say today. It seems strange, but for millions of years these rulers of the Earth were in the shadow of stronger and more adapted creatures, losing to them in all respects. And then something happened that destroyed the competition and made room for the dinosaurs.
What are these sensational statements based on? The argument was the many new fossils found in recent years that have radically changed the traditional concept of dinosaurs. So their history will have to be rewritten. Anyway, now it does not look so monumental.
It began, according to the famous Scottish paleontologist Stephen Brusset, about 252 million years ago. Then a natural catastrophe occurred on the planet, streams of hot lava burst from the depths to the surface, which flooded huge areas, volcanoes threw poisonous gases and millions of tons of lava and ash into the atmosphere. As a result, about 95 percent of living beings disappeared from the face of the Earth.
When nature calmed down and the Earth healed its wounds, the survivors began to thrive. So, scientists have found in Poland traces of the forefather of dinosaurs, he was called "prorotodactyl". He was about the size of a domestic cat and walked on long legs. Its age is about 250 million years, that is, it appeared only 1-2 million years after a terrible catastrophe. There were few of them, about 5 percent of the total number of creatures living then. And then within 10-15 million years, the ancestors of dinosaurs began to grow in the literal and figurative sense. And gradually they turned into real dinosaurs, which began to spread on the planet.
Steve Brusset emphasizes that they did not dominate the Earth at all. For 30 million years, they accounted for a maximum of 20 percent of all living things. And then the planet was dominated by close relatives of dinosaurs, who became the ancestors of the crocodile evolutionary branch, the creatures of pseudo-suchia. They turned out to be more adapted to life. They were small predators, but some reached sizes up to 5 meters. According to Brusset, in those days dinosaurs were a minor group of animals, and it is difficult to imagine that very soon, by historical standards, they will reach enormous proportions and become the rulers of the world.
What happened? How did these lizards get from rags to riches about 220 million years ago? Here is Brusset's version. He recalls that in those days, land was a single supercontinent Pangea. It began to split under the influence of powerful geological processes. As 252 million years ago, hot lava gushed from the bowels, volcanoes revived. That is, the catastrophic scenario has largely repeated itself. Many living creatures were rapidly dying out, and pseudo-ears almost completely disappeared. Amazingly, the blow of nature had little effect on the dinosaurs. It seems that they were able to benefit from the chaos reigning on the planet. As if they had been waiting for their time for 30 million years, and now, having got rid of the pseudo-aura, they quickly began to flourish, becoming the complete masters of the Earth.
But how is such a miracle possible? Brusset has no answer. “This is a mystery for the next generation of paleontologists to solve,” says the scientist. By the way, he was one of the authors of the now popular hypothesis about the fateful moment in the fate of the dinosaurs. Seconds decided everything! This conclusion was made after the study of Chicxulub crater, which arose in the Gulf of Mexico 66 million years ago from the fall of a 10 kilometer asteroid. Then released energy equivalent to the explosion of 10 billion atomic bombs dropped on Hiroshima. But there was nothing terrible in the fall of the asteroid, says Steve Brusset. If the asteroid had collapsed a few seconds earlier or later, it would not have crashed into the Earth and would not have lifted gigantic masses of matter into the air, which changed the climate so that the lizards lost their food. If a meteorite had fallen in another moment, it would have fallen into the deep ocean,would evaporate a lot less rocks, and the sun's rays would make their way to the surface of the Earth.
In a word, there would not have been a global cataclysm on Earth that destroyed many creatures, including dinosaurs. And then mammals, who lived in the shadow of reptiles for 100 million years, would not have replaced them. Having gained freedom, mammals occupied almost all the dominant "posts" on the planet. And finally, in the course of their evolution, our distant ancestors, primates, appeared. It turns out that evolution is a rather random process, and some event can radically change the situation. The most prosperous, dominant communities can disappear from the face of the Earth in an instant by historical standards.
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Yuri Medvedev