Dinosaurs, the gigantic creatures that dominated the Earth for over 160 million years, have captured the human imagination since the discovery of their first fossils. To understand how these fascinating creatures came to be, one must go back to the Paleozoic era, when life on Earth began to diversify significantly. The story of dinosaurs begins at the end of the Permian, about 252 million years ago, shortly after the largest mass extinction our planet has ever experienced, which wiped out nearly 96% of all marine animal species and 70% of all terrestrial vertebrate species. This mass extinction created an ecological vacuum and provided fertile ground for the emergence of new life forms in the next period, the Triassic. At the beginning of the Triassic, Earth presented a completely different landscape: a single supercontinent called Pangaea, characterized by extreme climatic conditions. In these harsh conditions, a group of vertebrates called archosaurs began to evolve and diversify. These archosaurs, which shared a common ancestor with crocodiles and modern birds, were the precursors of dinosaurs. Towards the end of the Triassic period, about 245 million years ago, the first true dinosaurs appeared. Scientists generally agree that dinosaurs' distinctive features, such as their upright posture—with legs placed vertically beneath the body—and an anteorbital fenestra (an opening in the skull in front of the eye sockets), represented a significant evolution over their archosaur ancestors. These adaptations allowed dinosaurs to become the dominant land animals thanks to their efficiency in locomotion and hunting, giving them a significant advantage over other land animals of their time. The earliest dinosaurs included creatures such as Eoraptor and Herrerasaurus, which were relatively small but extremely agile, allowing them to hunt efficiently in the arid and often inhospitable environments of Pangea. During the Triassic, dinosaurs began to diversify into two main groups: the Saurischia, or lizard-hipped dinosaurs, which included ferocious carnivores and giant bipedal herbivores, and the Ornithischia, or bird-hipped dinosaurs, which were primarily herbivores. This diversification was accompanied by an increasing variety of shapes and sizes, allowing dinosaurs to inhabit a wide range of habitats throughout Pangaea. The Triassic-Jurassic transition, about 201 million years ago, was marked by another mass extinction, but less devastating than that of the Permian. This extinction again reshaped terrestrial ecosystems, allowing dinosaurs to consolidate their dominance over the continents. During the Jurassic, many existing dinosaur groups continued to diversify, and new groups such as brachiosaurs and stegosaurs emerged. Often referred to as the Age of Dinosaurs, the Mesozoic Era was a time of unchallenged dominance by these creatures, with diversity reaching its peak during the Cretaceous Period, the final period of the Mesozoic Era. During this time, iconic dinosaurs such as Tyrannosaurus rex and Triceratops roamed the earth, while others, such as pterosaurs, conquered the skies. The dominance of dinosaurs came to an abrupt end around 66 million years ago, when a mass extinction, likely triggered by an asteroid impact, marked the end of the Cretaceous and Mesozoic periods. This catastrophic event put an end to the dinosaurs' reign and allowed other life forms, particularly mammals, to rise to prominence and evolve into the diversity we see today. This channel is an official affiliate of the ORBINEA STUDIO network