Dinosaurs
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Dinosaurs
Before the catastrophic extinction of dinosaurs, approximately 65 million years ago, these vertebrate animals dominated the ecosystem of earth and paved the way for modern anthropology. The sentiment of dinosaurs is even seen today, where modern birds are considered as direct descendents of the theropod. The three main periods of evolution in dinosaurs are the Triassic, Jurassic, and Cretaceous periods.
The Triassic period of the Mesozoic era, roughly 205 – 250 million years ago, was seen as a time of transition as dominant reptiles evolved on land as well as amphibious and marine animals of the sea. Due to the predominantly arid climate of the ecosystem at that time, cold-blooded reptiles gained dominance over warm-blooded mammal-like animals. The Triassic period also marked the induction of the Pterosaurs, which were flying reptiles.
Beginning approximately 210 million years ago, the Jurassic period lasted for 70 million years of the Mesozoic Era. By Late Jurassic, huge dinosaurs such as Stegosaurus, Ceratosaurus, Brachiosaurus, and Allosaurus walked the lands. Flying reptiles ruled the skies. The earliest known birds also appeared. The Jurassic period is known as the “Age of Dinosaurs” because the most rapid evolution occurred during this time, and the climate improved as lush vegetation evolved feeding the herbivore dinosaurs, and ultimately the entire food chain.
The Cretaceous period is generally known as being the end of the “Age of Dinosaurs”, but evolution and the emergence of a few species of dinosaurs occurred. The Cretaceous period is also the period many scientists date the appearance of the fossils of the first insects, modern bird groups, modern mammal groups, as well as the first flowering plants. During this time, the massive continent of Pangaea, which began to break up during the Jurassic period, continued and began to drift into different climate conditions and eventually to the land formations of earth that we know today. The end of the Cretaceous period also brought the end to many of the dominant animals on earth, paving the way for the less powerful to evolve and reflect on the world coming together as we know it today.