History of Dinosaurs and cause of their extinction - The Jurassic era of our earth

 

It is the story of the time when on our earth the dinosaurs used to live. It is about 65 million years ago the giant dinosaurs roaming in grasslands and these battleship size creatures dominate the skies. The mammals of that era were very small they were not like today’s rhinos; hippopotamus as they were not evolved because the big chunk of food was consumed by mighty dinosaurs. 

With time these mighty creatures became extinct, what had happened to these creatures and what killed dinosaurs and what is history of dinosaurs the researchers are working hard to find these answers. Here are possible causes for the extinction of these huge size creatures.

The time in which dinosaurs were alive is known as the Mesozoic era. This long time frame is divided into three periods. First was a Triassic period, second the Jurassic period, third the cretaceous period. The Triassic period was 250 – 200 million years ago the interesting thing of that period was the earth has only one continent called Pangaea the super-continent it was the only continent on earth surrounded by sea. Climate was warm and dry and a large portion of land consists of desert. It was a period in which dinosaurs were evolved. The hot and dry climate was great for the evolution of reptiles. There were no polar ice caps present on today’s planet earth. The movement of tectonic plates caused a massive earthquake and volcanic eruptions and Pangaea the super-continent gradually divided into two parts and due to this division, the North Atlantic Ocean appears. The volcanic eruptions and earthquakes caused the mass extinction of certain species of animals and birds, but dinosaurs survived, and an increase in their numbers take place certain species of dinosaurs evolve in that period, and here the first Triassic period ends and the Jurassic period begins.

The Jurassic Period extending from 201 million years to 145 million years ago. The temperature of the earth was decreased but higher than today’s temperature because of a high level of carbon dioxide.

The Cretaceous period extending from 145-65 million years ago, in that period the two continents further divided into many. The dinosaurs were rambling in these continents and certain species of snake were evolved in this period. Snakes did never exist before 140-60 million years ago. The evolution of flowering plants and bees takes place and many small mammals emerged in this period. At the end of the cretaceous period about a 65million years ago, the dinosaurs went extinct, and here the evolution of humans takes place.  

 

 

It was the cretaceous period in which three-fourths of animals and plants went extinct and dinosaurs were also included in this list. This disaster is known as K-T extinction. Dr: Luis Alvarez his son Dr: Walter and colleagues researched this mass extinction. In 1964 they collected the samples of rocks and examined in the University of California they astonished by the results, they found the iridium in the samples of K-T boundary’s rock (the impact site of dino killer asteroid) the iridium was 600 time than normal rock. Iridium is a metal that is rare on earth but found abundantly in space.

In 1981 he presented the findings of his research which is known as the Alvarez hypothesis or theory. He claimed in his hypothesis that high traces of iridium in the rock indicate that about a million years ago the large asteroid impact on earth this hypothesis strengthen when the impact site discovered in Yucatan, Mexico, and the impact create 180 km wide and 20 km deep crater and it was an incident which causes the extinction of dinosaurs.

 

 

These asteroids were the small pieces of rocks that during the genesis of our solar system unite together and form planets but leftover asteroids unable to combine to form any planet stuck between Mars and Jupiter and form the asteroid belt because of the strong gravity of Jupiter. If some asteroids escaped from the gravity of Jupiter fell towards the sun and the escaped asteroid collide with planets lying on their way towards the sun.           

 Occasionally in one of the asteroids 10 km in length impact our earth million years ago. The earth was full of life at that time. Under the radius of 1000 km, every living being vanished and the intensity was so many times higher than the detonation of the entire nuclear weapons stockpile of all nuclear power countries. After impact storm of dust besiege the sky and causes the long night and this is known as nuclear winter. In nuclear winter 75 percent of living beings had been vanished especially those who were large and cannot take shelter in caves and require food in higher quantity and dinosaurs were top of the list and that is what killed the dinosaurs.

There are other theories about the extinction of dinosaurs according to some scientists dinosaurs possess very large sizes but they have a skull of small size with a little brain this could be a possible cause of their extinction.

According to some researchers, climate change could be another reason for the extinction of dinosaurs according to this theory Pangaea the super-continent divided into other continents then there may be a scarcity of food and water in new continents which could be the reason for their extinction.          

 Some researchers also believe that temperature change could be the cause of dinosaur's extinction as they were cold-blooded animals that cannot adapt themselves according to new climatic conditions and changes in temperature. Some researchers think the epidemics could be the cause of their extinction. There is another group of scientists who believe that small mammals could be the cause of their extinction as these small mammals were eating the nutritious eggs of dinosaurs. According to research, a massive volcanic eruption takes place in India about 60 million years ago the discharge of poisonous gases into an atmosphere change the global climate this also could lead to the extinction of dinosaurs. 

    The new researches are being conducted to answer one question that how the dinosaurs were living and how they became extinct. One question arise in our mind that does dinosaurs still alive

     And it is revealed in a new research study that theropod the flesh-eating species of dinosaurs, having the ability to fly managed to exist and by the passage of time they are evolved into birds. 

This is the story of dinosaurs from origin to extinction.