Dinosaurs

Dinosaurs

The dinosaurs appeared about 245 million years ago during Triassic Period when most of Earth's landmasses were still joined together as the super continent Over million of years Pangea split apart into Laurasia and Gondwanaland, causing dinosaurs to adapt to 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 Archosaurus,

from which dinosaurs branched out two major groups, Saurichia and Ornithiscia. They separated based on the shape and orientation of their pelvis. We don't know what caused them to evolve is big size but we believe that one factor is that they laid eggs which hatched and grew outside the mother's body and the other factor is that their skeletons had air sacks around neck, back and hip, so they could move easily without losing strength.

 

The most popular dinosaurs are Plesiosaurus, Velisoraptor, Tyranosaurus Rex, Spinosaurus, Triceratops and Brachiosaurus. 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 due to 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, out of which ones evolved to become today's birds.

 

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Watch the next video to find out more about dinosaurs' extinction.